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? 7/99 microchip technology inc. preliminary ds39026b-page 1 high performance risc cpu: ? c-compiler optimized architecture/instruction set - source code compatible with the pic16cxx instruction set ? linear program memory addressing to 2m bytes ? linear data memory addressing to 4k bytes ? up to 10 mips operation: - dc - 40 mhz osc./clock input - 4 mhz - 10 mhz osc./clock input with pll active ? 16-bit wide instructions, 8-bit wide data path ? priority levels for interrupts ? 8 x 8 single cycle hardware multiplier peripheral features: ? high current sink/source 25 ma/25 ma ? three external interrupt pins ? timer0 module: 8-bit/16-bit timer/counter with 8-bit programmable prescaler ? timer1 module: 16-bit timer/counter ? timer2 module: 8-bit timer/counter with 8-bit period register (time-base for pwm) ? timer3 module: 16-bit timer/counter ? secondary oscillator clock option - timer1/timer3 ?two capture/compare/pwm (ccp) modules. ccp pins that can be configured as: - capture input: capture is 16-bit, max. resolution 6.25 ns (t cy /16) - compare is 16-bit, max. resolution 100 ns (t cy ) - pwm output: pwm resolution is 1- to 10-bit. max. pwm freq. @:8-bit resolution = 156 khz 10-bit resolution = 39 khz ? master synchronous serial port (mssp) module. two modes of operation: - 3-wire spi? (supports all 4 spi modes) -i 2 c? master and slave mode ? addressable usart module: - supports interrupt on address bit ? parallel slave port (psp) module pin diagrams analog features: ? 10-bit analog-to-digital converter module (a/d) with: - fast sampling rate - conversion available during sleep - dnl = 1 lsb, inl = 1 lsb ? programmable low-voltage detection (lvd) module - supports interrupt on low voltage detection ? programmable brown-out reset (bor) special microcontroller features: ? power-on reset (por), power-up timer (pwrt) and oscillator start-up timer (ost) ? watchdog timer (wdt) with its own on-chip rc oscillator for reliable operation ? programmable code-protection ? power saving sleep mode ? selectable oscillator options including: - 4x phase lock loop (of primary oscillator) - secondary oscillator (32 khz) clock input ? in-circuit serial programming (icsp?) via two pins cmos technology: ? low-power, high-speed eprom technology ? fully static design ? wide operating voltage range (2.5v to 5.5v) ? industrial and extended temperature ranges ? low-power consumption device on-chip program memory on-chip ram (bytes) eprom (bytes) # single word instructions pic18c242 16k 8192 512 pic18c252 32k 16384 1536 pic18c442 16k 8192 512 pic18c452 32k 16384 1536 * * * * * rb7 rb6 rb5 rb4 rb3/ccp2 * rb2/int2 rb1/int1 rb0/int0 v dd v ss rd7/psp7 rd6/psp6 rd5/psp5 rd4/psp4 rc7/rx/dt rc6/tx/ck rc5/sdo rc4/sdi/sda rd3/psp3 rd2/psp2 mclr /v pp ra0/an 0 ra1/an1 ra2/an2/v ref - ra3/an3/v ref + ra4/t0cki ra5/an4/ss /lvdin re0/rd/an5 re1/wr/an6 re2/cs/an7 v dd v ss osc1/clki osc2/clko/ra6 rc0/t1oso/t1cki rc1/t1osi/ccp2 * rc2/ccp1 rc3/sck/scl rd0/psp0 rd1/psp1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 pic18c4x2 * rb3 is the alternate pin for the ccp2 pin multiplexing. dip, windowed cerdip note: pin compatible with 40-pin pic16c7x devices pic18cxx2 high-performance microcontrollers with 10-bit a/d
ds39026b-page 2 preliminary ? 7/99 microchip technology inc. pic18cxx2 pin diagrams 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 44 8 7 6 5 4 3 2 1 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 9 pic18c4x2 ra4/t0cki ra5/an4/ss /lvdin re0/rd /an5 osc2/clko/ra6 nc re1/wr/an6 re2/cs /an7 v dd osc1/clki rb3/ccp2 * rb2/int2 rb1/int1 rb0/int0 v dd v ss rd7/psp7 rd6/psp6 rd5/psp5 rd4/psp4 rc7/rx/dt ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 mclr /v pp nc rb7 rb6 rb5 rb4 nc nc rc6/tx/ck rc5/sdo rc4/sdi/sda rd3/psp3 rd2/psp2 rd1/psp1 rd0/psp0 rc3/sck/scl rc2/ccp1 rc1/t1osi/ccp2 * 10 11 2 3 4 5 6 1 18 19 20 21 22 12 13 14 15 38 8 7 44 43 42 41 40 39 16 17 29 30 31 32 33 23 24 25 26 27 28 36 34 35 9 pic18c4x2 37 ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 mclr /v pp nc rb7 rb6 rb5 rb4 nc rc6/tx/ck rc5/sdo rc4/sdi/sda rd3/psp3 rd2/psp2 rd1/psp1 rd0/psp0 rc3/sck/scl rc2/ccp1 rc1/t1osi/ccp2 * nc nc rc0/t1oso/t1cki osc2/clko/ra6 osc1/clki v ss v dd re2/an7/cs re1/an6/wr re0/an5/rd ra5/an4/ss /lvdin ra4/t0cki rc7/rx/dt rd4/psp4 rd5/psp5 rd6/psp6 rd7/psp7 v ss v dd rb0/int0 rb1/int1 rb2/int2 rb3/ccp2 * plcc tqfp * rb3 is the alternate pin for the ccp2 pin multiplexing. note: pin compatible with 44-pin pic16c7x devices v ss rc0/t1oso/t1cki
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 3 pin diagrams (cont.d) rb7 rb6 rb5 rb4 rb3/ccp2 * rb2/int2 rb1/int1 rb0/int0 v dd v ss rd7/psp7 rd6/psp6 rd5/psp5 rd4/psp4 rc7/rx/dt rc6/tx/ck rc5/sdo rc4/sdi/sda rd3/psp3 rd2/psp2 mclr /v pp ra0/an0 ra1/an1 ra2/an2/v ref - ra3/an3/v ref + ra4/t0cki ra5/an4/ss /lvdin re0/rd /an5 re1/wr /an6 re2/cs /an7 v dd v ss osc1/clki osc2/clko/ra6 rc0/t1oso/t1cki rc1/t1osi/ccp2 * rc2/ccp1 rc3/sck/scl rd0/psp0 rd1/psp1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 pic18c4x2 pic18c2x2 10 11 2 3 4 5 6 1 8 7 9 12 13 14 15 16 17 18 19 20 23 24 25 26 27 28 22 21 mclr /v pp ra0/an0 ra1/an1 ra2/an2/v ref - ra3/an3/v ref + ra4/t0cki ra5/an4/ss /lvdin v ss osc1/clki osc2/clko/ra6 rc0/t1oso/t1cki rc1/t1osi/ccp2 * rc2/ccp1 rc3/sck/scl rb7 rb6 rb5 rb4 rb3/ccp2 * rb2/int2 rb1/int1 rb0/int0 v dd v ss rc7/rx/dt rc6/tx/ck rc5/sdo rc4/sdi/sda * rb3 is the alternate pin for the ccp2 pin multiplexing. dip, jw dip, soic, jw note: pin compatible with 40-pin pic16c7x devices note: pin compatible with 28-pin pic16c7x devices
ds39026b-page 4 preliminary ? 7/99 microchip technology inc. pic18cxx2 table of contents 1.0 device overview ............................................................................................................. ............................................................. 5 2.0 oscillator configurations ................................................................................................... ......................................................... 15 3.0 reset ....................................................................................................................... ................................................................... 23 4.0 memory organization ......................................................................................................... ........................................................ 33 5.0 table reads/table writes .................................................................................................... ...................................................... 53 6.0 8 x 8 hardware multiplier ................................................................................................... ........................................................ 61 7.0 interrupts .................................................................................................................. .................................................................. 65 8.0 i/o ports ................................................................................................................... .................................................................. 77 9.0 timer0 module ............................................................................................................... ............................................................ 93 10.0 timer1 module .............................................................................................................. ............................................................. 97 11.0 timer2 module .............................................................................................................. ........................................................... 102 12.0 timer3 module .............................................................................................................. ........................................................... 105 13.0 capture/compare/pwm (ccp) modules .......................................................................................... ....................................... 109 14.0 master synchronous serial port (mssp) module ............................................................................... ..................................... 117 15.0 addressable universal synchronous asynchronous receiver transmitter (usart)................................................ .............. 151 16.0 10-bit analog-to-digital converter (a/d) module ............................................................................ .......................................... 167 17.0 low voltage detect ......................................................................................................... ......................................................... 175 18.0 special features of the cpu ................................................................................................ .................................................... 181 19.0 instruction set summary .................................................................................................... ...................................................... 191 20.0 development support........................................................................................................ ....................................................... 235 21.0 electrical characteristics ................................................................................................. ......................................................... 241 22.0 dc and ac characteristics graphs and tables ................................................................................ ....................................... 273 23.0 packaging information...................................................................................................... ........................................................ 275 appendix a: revision history .................................................................................................... ..................................................... 283 appendix b: device differences.................................................................................................. ................................................... 283 appendix c: conversion considerations........................................................................................... ............................................. 284 appendix d: migration from baseline to enhanced devices ......................................................................... ................................. 284 appendix e: migration from midrange to enhanced devices ......................................................................... ................................ 285 appendix f: migration from high-end to enhanced devices ......................................................................... ................................ 285 index ......................................................................................................................... ........................................................................ 287 on-line support................................................................................................................ ................................................................. 293 reader response ................................................................................................................ .............................................................. 294 pic18cxx2 product identification system ........................................................................................ ................................................ 295 to our valued customers most current data sheet to obtain the most up-to-date version of this data sheet, please register at our worldwide web site at: http://www.microchip.com you can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page . the last character of the literature number is the version number. e.g., ds30000a is version a of document ds30000. new customer notification system register on our web site (www.microchip.com/cn) to receive the most current information on our 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7/99 microchip technology inc. preliminary ds39026b-page 5 pic18cxx2 1.0 device overview this document contains device-specific information for the following four devices: 1. pic18c242 2. pic18c252 3. pic18c442 4. pic18c452 these devices come in 28 and 40-pin packages. the 28-pin devices do not have a parallel slave port (psp) implemented and the number of analog-to-digital (a/d) converter input channels is reduced to 5. an overview of features is shown in table 1-1. the following two figures are device block diagrams sorted by pin count; 28-pin for figure 1-1 and 40-pin for figure 1-2. the 28-pin and 40-pin pinouts are listed in table 1-2 and table 1-3 respectively. table 1-1: device features features pic18c242 pic18c252 pic18c442 pic18c452 operating frequency dc - 40 mhz dc - 40 mhz dc - 40 mhz dc - 40 mhz program memory (bytes) 16k 32k 16k 32k program memory (instructions) 8192 16384 8192 16384 data memory (bytes) 512 1536 512 1536 interrupt sources 16 16 17 17 i/o ports ports a, b, c ports a, b, c ports a, b, c, d, e ports a, b, c, d, e timers 4 4 4 4 capture/compare/pwm modules 2 2 2 2 serial communications mssp, addressable usart mssp, addressable usart mssp, addressable usart mssp, addressable usart parallel communications psp psp 10-bit analog-to-digital module 5 input channels 5 input channels 8 input channels 8 input channels resets (and delays) por, bor, reset instruction, stack full, stack underflow (pwrt, ost) por, bor, reset instruction, stack full, stack underflow (pwrt, ost) por, bor, reset instruction, stack full, stack underflow (pwrt, ost) por, bor, reset instruction, stack full, stack underflow (pwrt, ost) programmable low voltage detect yes yes yes yes programmable brown-out reset yes yes yes yes instruction set 75 instructions 75 instructions 75 instructions 75 instructions packages 28-pin dip 28-pin soic 28-pin jw 28-pin dip 28-pin soic 28-pin jw 40-pin dip 40-pin plcc 40-pin tqfp 40-pin jw 40-pin dip 40-pin plcc 40-pin tqfp 40-pin jw
pic18cxx2 ds39026b-page 6 preliminary 7/99 microchip technology inc. figure 1-1: pic18c2x2 block diagram power-up timer oscillator start-up timer power-on reset watchdog timer instruction decode & control osc1/clki osc2/clko mclr v dd , v ss porta portb portc ra4/t0cki ra5/an4/ss /lvdin rb0/int0 rb7:rb4 rc0/t1oso/t1cki rc1/t1osi/ccp2 ( 1 ) rc2/ccp1 rc3/sck/scl rc4/sdi/sda rc5/sdo rc6/tx/ck rc7/rx/dt brown-out reset note 1: optional multiplexing of ccp2 input/output with rb3 is enabled by selection of configuration bit. 2: the high order bits of the direct address for the ram are from the bsr register (except for the movff instruction). 3: many of the general purpose i/o pins are multiplexed with one or more peripheral module functions. the multiplexing combinations are device dependent. addressable ccp1 synchronous timer0 timer1 timer2 serial port ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 timing generation 4x pll a/d converter precision reference rb1/int1 data latch data ram address latch address<12> 12 ( 2 ) bsr fsr0 fsr1 fsr2 4 12 4 pch pcl pclath 8 31 level stack program counter prodl prodh 8 x 8 multiply wreg 8 bit op 8 8 alu<8> 8 address latch program memory (up to 2m bytes) data latch 20 21 21 16 8 8 8 inc/dec logic 21 8 data bus<8> 8 instruction 12 3 romlatch timer3 ccp2 rb2/int2 rb3/ccp2 ( 1 ) t1osi t1oso bank0, f pclatu pcu ra6 voltage usart master 8 register tablelatch ta b l e po i n t e r < 2 > inc/dec logic decode
7/99 microchip technology inc. preliminary ds39026b-page 7 pic18cxx2 figure 1-2: pic18c4x2 block diagram power-up timer oscillator start-up timer power-on reset watchdog timer instruction decode & control osc1/clki osc2/clko mclr v dd , v ss porta portb portc ra4/t0cki ra5/an4/ss /lvdin rb0/int0 rb7:rb4 rc0/t1oso/t1cki rc1/t1osi/ccp2 ( 1 ) rc2/ccp1 rc3/sck/scl rc4/sdi/sda rc5/sdo rc6/tx/ck rc7/rx/dt brown-out reset note 1: optional multiplexing of ccp2 input/output with rb3 is enabled by selection of configuration bit. 2: the high order bits of the direct address for the ram are from the bsr register (except for the movff instruction). 3: many of the general purpose i/o pins are multiplexed with one or more peripheral module functions. the multiplexing combinations are device dependent. addressable ccp1 master timer0 timer1 timer2 serial port ra3/an3/v ref + ra2/an2/v ref - ra1/an1 ra0/an0 parallel slave port timing generation 4x pll a/d converter rb1/int1 data latch data ram (up to 4k address reach) address latch address<12> 12 ( 2 ) bank0, f bsr fsr0 fsr1 fsr2 4 12 4 pch pcl pclath 8 31 level stack program counter prodl prodh 8 x 8 multiply wreg 8 bit op 8 8 alu<8> 8 address latch program memory (up to 2m bytes) data latch 20 21 21 16 8 8 8 inc/dec logic 21 8 data bus<8> tablelatch 8 instruction 12 3 romlatch timer3 portd porte rd7/psp7:rd0/psp0 re0/an5/rd re1/an6/wr re2/an7/cs ccp2 rb2/int2 rb3/ccp2 ( 1 ) t1osi t1oso pclatu pcu ra6 precision reference voltage synchronous usart register 8 ta bl e po i n te r < 2 > inc/dec logic decode
pic18cxx2 ds39026b-page 8 preliminary 7/99 microchip technology inc. table 1-2: pic18c2x2 pinout i/o descriptions pin name pin number pin type buffer type dip soic description mclr /v pp mclr v pp 11 i p st master clear (reset) input. this pin is an active low reset to the device. programming voltage input. nc these pins should be left unconnected. osc1/clki osc1 clki 99 i i st cmos oscillator crystal input or external clock source input. st buffer when configured in rc mode. cmos otherwise. external clock source input. always associated with pin function osc1. (see related osc1/clkin, osc2/clkout pins). osc2/clko/ra6 osc2 clko ra6 10 10 o o i/o ttl oscillator crystal output. connects to crystal or resonator in crystal oscillator mode. in rc mode, osc2 pin outputs clkout which has 1/4 the frequency of osc1, and denotes the instruction cycle rate. general purpose i/o pin. porta is a bi-directional i/o port. ra0/an0 ra0 an0 22 i/o i ttl analog digital i/o. analog input 0. ra1/an1 ra1 an1 33 i/o i ttl analog digital i/o. analog input 1. ra2/an2/v ref - ra2 an2 v ref - 44 i/o i i ttl analog analog digital i/o. analog input 2. a/d reference voltage (low) input. ra3/an3/v ref + ra3 an3 v ref + 55 i/o i i ttl analog analog digital i/o. analog input 3. a/d reference voltage (high) input. ra4/t0cki ra4 t0cki 66 i/o i st/od st digital i/o. open drain when configured as output. timer0 external clock input. ra5/an4/ss /lvdin ra5 an4 ss lv d i n 77 i/o i i i ttl analog st analog digital i/o. analog input 4. spi slave select input. low voltage detect input. ra6 see the osc2/clko/ra6 pin. legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
7/99 microchip technology inc. preliminary ds39026b-page 9 pic18cxx2 portb is a bi-directional i/o port. portb can be software programmed for internal weak pull-ups on all inputs. rb0/int0 rb0 int0 21 21 i/o i ttl st digital i/o. external interrupt 0. rb1/int1 rb1 int1 22 22 i/o i ttl st external interrupt 1. rb2/int2 rb2 int2 23 23 i/o i ttl st digital i/o. external interrupt 2. rb3/ccp2 rb3 ccp2 24 24 i/o i/o ttl st digital i/o. capture2 input, compare2 output, pwm2 output. rb4 25 25 i/o ttl digital i/o. interrupt on change pin. rb5 26 26 i/o ttl digital i/o. interrupt on change pin. rb6 27 27 i/o i ttl st digital i/o. interrupt on change pin. icsp programming clock. rb7 28 28 i/o i/o ttl st digital i/o. interrupt on change pin. icsp programming data. table 1-2: pic18c2x2 pinout i/o descriptions (c ont.d) pin name pin number pin type buffer type dip soic description legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
pic18cxx2 ds39026b-page 10 preliminary 7/99 microchip technology inc. portc is a bi-directional i/o port. rc0/t1oso/t1cki rc0 t1oso t1cki 11 11 i/o o i st st digital i/o. timer1 oscillator output. timer1/timer3 external clock input. rc1/t1osi/ccp2 rc1 t1osi ccp2 12 12 i/o i i/o st cmos st digital i/o. timer1 oscillator input. capture2 input, compare2 output, pwm2 output. rc2/ccp1 rc2 ccp1 13 13 i/o i/o st st digital i/o. capture1 input/compare1 output/pwm1 output. rc3/sck/scl rc3 sck scl 14 14 i/o i/o i/o st st st digital i/o. synchronous serial clock input/output for spi mode. synchronous serial clock input/output for i 2 c mode rc4/sdi/sda rc4 sdi sda 15 15 i/o i i/o st st st digital i/o. spi data in. i 2 c data i/o. rc5/sdo rc5 sdo 16 16 i/o o st digital i/o. spi data out. rc6/tx/ck rc6 tx ck 17 17 i/o o i/o st st digital i/o. usart asynchronous transmit. usart synchronous clock. (see related rx/dt) rc7/rx/dt rc7 rx dt 18 18 i/o i i/o st st st digital i/o. usart asynchronous receive. usart synchronous data. (see related tx/ck) v ss 8, 19 8, 19 p ground reference for logic and i/o pins. v dd 20 20 p positive supply for logic and i/o pins. table 1-2: pic18c2x2 pinout i/o descriptions (c ont.d) pin name pin number pin type buffer type dip soic description legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
7/99 microchip technology inc. preliminary ds39026b-page 11 pic18cxx2 table 1-3: pic18c4x2 pinout i/o descriptions pin name pin number pin type buffer type dip plcc tqfp description mclr /v pp mclr v pp 1218 i p st master clear (reset) input. this pin is an active low reset to the device. programming voltage input. nc these pins should be left unconnected. osc1/clki osc1 clki 13 14 30 i i st cmos oscillator crystal input or external clock source input. st buffer when configured in rc mode. cmos otherwise. external clock source input. always associated with pin function osc1. (see related osc1/clkin, osc2/clkout pins). osc2/clko/ra6 osc2 clko ra6 14 15 31 o o i/o ttl oscillator crystal output. connects to crystal or resonator in crystal oscillator mode. in rc mode, osc2 pin outputs clkout, which has 1/4 the frequency of osc1 and denotes the instruction cycle rate. general purpose i/o pin. porta is a bi-directional i/o port. ra0/an0 ra0 an0 2319 i/o i ttl analog digital i/o. analog input 0. ra1/an1 ra1 an1 3420 i/o i ttl analog digital i/o. analog input 1. ra2/an2/v ref - ra2 an2 v ref - 4521 i/o i i ttl analog analog digital i/o. analog input 2. a/d reference voltage (low) input. ra3/an3/v ref + ra3 an3 v ref + 5622 i/o i i ttl analog analog digital i/o. analog input 3. a/d reference voltage (high) input. ra4/t0cki ra4 t0cki 6723 i/o i st/od st digital i/o. open drain when configured as output. timer0 external clock input. ra5/an4/ss /lvdin ra5 an4 ss lv d i n 7824 i/o i i i ttl analog st analog digital i/o. analog input 4. spi slave select input. low voltage detect input. ra6 see the osc2/clko/ra6 pin. legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
pic18cxx2 ds39026b-page 12 preliminary 7/99 microchip technology inc. portb is a bi-directional i/o port. portb can be software programmed for internal weak pull-ups on all inputs. rb0/int0 rb0 int0 33 36 8 i/o i ttl st digital i/o. external interrupt 0. rb1/int1 rb1 int1 34 37 9 i/o i ttl st external interrupt 1. rb2/int2 rb2 int2 35 38 10 i/o i ttl st digital i/o. external interrupt 2. rb3/ccp2 rb3 ccp2 36 39 11 i/o i/o ttl st digital i/o. capture2 input, compare2 output, pwm2 output. rb4 37 41 14 i/o ttl digital i/o. interrupt on change pin. rb5 38 42 15 i/o ttl digital i/o. interrupt on change pin. rb6 39 43 16 i/o i ttl st digital i/o. interrupt on change pin. icsp programming clock. rb7 40 44 17 i/o i/o ttl st digital i/o. interrupt on change pin. icsp programming data. table 1-3: pic18c4x2 pinout i/o descriptions (c ont.d) pin name pin number pin type buffer type dip plcc tqfp description legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
7/99 microchip technology inc. preliminary ds39026b-page 13 pic18cxx2 portc is a bi-directional i/o port. rc0/t1oso/t1cki rc0 t1oso t1cki 15 16 32 i/o o i st st digital i/o. timer1 oscillator output. timer1/timer3 external clock input. rc1/t1osi/ccp2 rc1 t1osi ccp2 16 18 35 i/o i i/o st cmos st digital i/o. timer1 oscillator input. capture2 input, compare2 output, pwm2 output. rc2/ccp1 rc2 ccp1 17 19 36 i/o i/o st st digital i/o. capture1 input/compare1 output/pwm1 output. rc3/sck/scl rc3 sck scl 18 20 37 i/o i/o i/o st st st digital i/o. synchronous serial clock input/output for spi mode. synchronous serial clock input/output for i 2 c mode. rc4/sdi/sda rc4 sdi sda 23 25 42 i/o i i/o st st st digital i/o. spi data in. i 2 c data i/o. rc5/sdo rc5 sdo 24 26 43 i/o o st digital i/o. spi data out. rc6/tx/ck rc6 tx ck 25 27 44 i/o o i/o st st digital i/o. usart asynchronous transmit. usart synchronous clock. (see related rx/dt) rc7/rx/dt rc7 rx dt 26 29 1 i/o i i/o st st st digital i/o. usart asynchronous receive. usart synchronous data. (see related tx/ck) table 1-3: pic18c4x2 pinout i/o descriptions (c ont.d) pin name pin number pin type buffer type dip plcc tqfp description legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
pic18cxx2 ds39026b-page 14 preliminary 7/99 microchip technology inc. portd is a bi-directional i/o port. parallel slave port (psp) for interfacing to a micropro- cessor port. these pins have ttl input buffers when psp module is enabled. rd0/psp0 19 21 38 i/o st ttl digital i/o. parallel slave port data. rd1/psp1 20 22 39 i/o st ttl digital i/o. parallel slave port data. rd2/psp2 21 23 40 i/o st ttl digital i/o. parallel slave port data. rd3/psp3 22 24 41 i/o st ttl digital i/o. parallel slave port data. rd4/psp4 27 30 2 i/o st ttl digital i/o. parallel slave port data. rd5/psp5 28 31 3 i/o st ttl digital i/o. parallel slave port data. rd6/psp6 29 32 4 i/o st ttl digital i/o. parallel slave port data. rd7/psp7 30 33 5 i/o st ttl digital i/o. parallel slave port data. porte is a bi-directional i/o port. re0/rd /an5 re0 rd an5 8 9 25 i/o st ttl analog digital i/o. read control for parallel slave port. (see also wr and cs pins) analog input 5. re1/wr /an6 re1 wr an6 9 10 26 i/o st ttl analog digital i/o. write control for parallel slave port. (see cs and rd pins) analog input 6. re2/cs /an7 re2 cs an7 10 11 27 i/o st ttl analog digital i/o. chip select control for parallel slave port. (see related rd and wr ) analog input 7. v ss 12, 31 13, 34 6, 29 p ground reference for logic and i/o pins. v dd 11, 32 12, 35 7, 28 p positive supply for logic and i/o pins. table 1-3: pic18c4x2 pinout i/o descriptions (c ont.d) pin name pin number pin type buffer type dip plcc tqfp description legend: ttl = ttl compatible input cmos = cmos compatible input or output st = schmitt trigger input with cmos levels i = input o = output p = power od = open drain (no p diode to v dd )
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 15 2.0 oscillator configurations 2.1 o scillator types the pic18cxx2 can be operated in eight different oscillator modes. the user can program three configu- ration bits (fosc2, fosc1, and fosc0) to select one of these eight modes: 1. lp low power crystal 2. xt crystal/resonator 3. hs high speed crystal/resonator 4. hs + pll high speed crystal/resonator with pll enabled 5. rc external resistor/capacitor 6. rcio external resistor/capacitor with i/o pin enabled 7. ec external clock 8. ecio external clock with i/o pin enabled 2.2 c rystal oscillator/ceramic resonators in xt, lp, hs or hs-pll oscillator modes, a crystal or ceramic resonator is connected to the osc1 and osc2 pins to establish oscillation. figure 2-1 shows the pin connections. an external clock source may also be connected to the osc1 pin in these modes, as shown in figure 2-2. the pic18cxx2 oscillator design requires the use of a parallel cut crystal. figure 2-1: crystal/ceramic resonator operation (hs, xt or lp osc configuration) figure 2-2: external clock input operation (hs, xt or lp osc configuration) note: use of a series cut crystal may give a fre- quency out of the crystal manufacturers specifications. note 1: see table 2-1 and table 2-2 for recom- mended values of c1 and c2. note 2: a series resistor (r s ) may be required for at strip cut crystals. note 3: r f varies with the crystal chosen. c1 (1) c2 (1) xtal osc2 osc1 r f (3) sleep to logic pic18cxxx r s (2) internal osc1 osc2 open clock from ext. system pic18cxxx
pic18cxx2 ds39026b-page 16 preliminary ? 7/99 microchip technology inc. table 2-1: ceramic resonators table 2-2: capacitor selection for crystal oscillator 2.3 rc oscillator for timing insensitive applications, the rc and "rcio" device options offer additional cost savings. the rc oscillator frequency is a function of the supply voltage, the resistor (r ext ) and capacitor (c ext ) val- ues and the operating temperature. in addition to this, the oscillator frequency will vary from unit to unit due to normal process parameter variation. furthermore, the difference in lead frame capacitance between package types will also affect the oscillation frequency, especially for low c ext values. the user also needs to take into account variation due to tolerance of external r and c components used. figure 2-3 shows how the r/c combination is connected. in the rc oscillator mode, the oscillator frequency divided by 4 is available on the osc2 pin. this signal may be used for test purposes or to synchronize other logic. figure 2-3: rc oscillator mode the rcio oscillator mode functions like the rc mode, except that the osc2 pin becomes an additional gen- eral purpose i/o pin. the i/o pin becomes bit 6 of porta (ra6). 2.4 external clock inpu t the ec and ecio oscillator modes require an external clock source to be connected to the osc1 pin. the feedback device between osc1 and osc2 is turned off in these modes to save current. there is no oscilla- tor startup time required after a power-on-reset or after a recovery from sleep mode. in the ec oscillator mode, the oscillator frequency divided by 4 is available on the osc2 pin. this signal may be used for test purposes or to synchronize other logic. figure 2-4 shows the pin connections for the ec oscillator mode. ranges tested: mode freq osc1 osc2 xt 455 khz 2.0 mhz 4.0 mhz 68 - 100 pf 15 - 68 pf 15 - 68 pf 68 - 100 pf 15 - 68 pf 15 - 68 pf hs 8.0 mhz 16.0 mhz 10 - 68 pf 10 - 22 pf 10 - 68 pf 10 - 22 pf these values are for design guidance only. see notes at bottom of page. resonators used: 455 khz panasonic efo-a455k04b 0.3% 2.0 mhz murata erie csa2.00mg 0.5% 4.0 mhz murata erie csa4.00mg 0.5% 8.0 mhz murata erie csa8.00mt 0.5% 16.0 mhz murata erie csa16.00mx 0.5% all resonators used did not have built-in capacitors. osc type crystal freq cap. range c1 cap. range c2 lp 32.0 khz 33 pf 33 pf 200 khz 15 pf 15 pf xt 200 khz 47-68 pf 47-68 pf 1.0 mhz 15 pf 15 pf 4.0 mhz 15 pf 15 pf hs 4.0 mhz 15 pf 15 pf 8.0 mhz 15-33 pf 15-33 pf 20.0 mhz 15-33 pf 15-33 pf 25.0 mhz tbd tbd these values are for design guidance only. see notes at bottom of page. crystals used 32.0 khz epson c-001r32.768k-a 20 ppm 200 khz std xtl 200.000khz 20 ppm 1.0 mhz ecs ecs-10-13-1 50 ppm 4.0 mhz ecs ecs-40-20-1 50 ppm 8.0 mhz epson ca-301 8.000m-c 30 ppm 20.0 mhz epson ca-301 20.000m-c 30 ppm note 1: recommended values of c1 and c2 are identical to the ranges tested (table 2-1). 2: higher capacitance increases the stability of the oscillator, but also increases the start- up time. 3: since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appropri- ate values of external components. 4: rs may be required in hs mode, as well as xt mode, to avoid overdriving crystals with low drive level specification. osc2/clko c ext r ext pic18cxxx osc1 f osc /4 internal clock v dd v ss recommended values: 3 k w r ext 100 k w c ext > 20pf
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 17 figure 2-4: external clock input operation (ec osc configuration) the ecio oscillator mode functions like the ec mode, except that the osc2 pin becomes an additional gen- eral purpose i/o pin. the i/o pin becomes bit 6 of porta (ra6). figure 2-5 shows the pin connections for the ecio oscillator mode. figure 2-5: external clock input operation (ecio configuration) 2.5 hs/pll a phase locked loop circuit is provided as a program- mable option for users that want to multiply the fre- quency of the incoming crystal oscillator signal by 4. for an input clock frequency of 10 mhz, the internal clock frequency will be multiplied to 40 mhz. this is useful for customers who are concerned with emi due to high frequency crystals. the pll can only be enabled when the oscillator con- figuration bits are programmed for hs mode. if they are programmed for any other mode, the pll is not enabled and the system clock will come directly from osc1. the pll is one of the modes of the fosc<2:0> con- figuration bits. the oscillator mode is specified during device programming. a pll lock timer is used to ensure that the pll has locked before device execution starts. the pll lock timer has a time-out that is called t pll . figure 2-6: pll block diagram osc1 osc2 f osc /4 clock from ext. system pic18cxxx osc1 i/o (osc2) ra6 clock from ext. system pic18cxxx mux vco loop filter divide by 4 crystal osc osc2 osc1 pll enable f in f out sysclk phase comparator (from configuration hs osc bit register)
pic18cxx2 ds39026b-page 18 preliminary ? 7/99 microchip technology inc. 2.6 oscillator switching feature the pic18cxx2 devices include a feature that allows the system clock source to be switched from the main oscillator to an alternate low frequency clock source. for the pic18cxx2 devices, this alternate clock source is the timer1 oscillator. if a low-frequency crys- tal (32 khz, for example) has been attached to the timer1 oscillator pins and the timer1 oscillator has been enabled, the device can switch to a low power execution mode. figure 2-7 shows a block diagram of the system clock sources. the clock switching feature is enabled by programming the oscillator switching enable (oscsen ) bit in configuration register1h to a 0. clock switching is disabled in an erased device. see section 9 for further details of the timer1 oscillator. see section 18.0 for configuration register details. figure 2-7: device clock sources 2.6.1 system clock switch bit the system clock source switching is performed under software control. the system clock switch bit, scs (osccon<0>) controls the clock switching. when the scs bit is 0, the system clock source comes from the main oscillator that is selected by the fosc configura- tion bits in configuration register1h. when the scs bit is set, the system clock source will come from the timer1 oscillator. the scs bit is cleared on all forms of reset. register 2-1: osccon register pic18cxxx t osc 4 x pll t t 1 p t sclk clock source mux to s c / 4 timer1 oscillator t1oscen enable oscillator t1oso t1osi clock source option for other modules osc1 osc2 sleep main oscillator note: the timer1 oscillator must be enabled to switch the system clock source. the timer1 oscillator is enabled by setting the t1oscen bit in the timer1 control register (t1con). if the timer1 oscillator is not enabled, then any write to the scs bit will be ignored (scs bit forced cleared) and the main oscillator will continue to be the system clock source. u-0 u-0 u-0 u-0 u-0 u-0 u-0 r/w-1 scs bit 7 bit 0 bit 7-1 unimplemented: read as '0' bit 0 scs: system clock switch bit when oscsen c onfiguration bit = 0 and t1oscen b it is set: 1 = switch to timer1 oscillator/clock pin 0 = use primary oscillator/clock input pin when oscsen and t1oscen a re in other states: bit is forced clear legend r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 19 2.6.2 oscillator transitions the pic18cxx2 devices contain circuitry to prevent "glitches" when switching between oscillator sources. essentially, the circuitry waits for eight rising edges of the clock source that the processor is switching to. this ensures that the new clock source is stable and that its pulse width will not be less than the shortest pulse width of the two clock sources. a timing diagram indicating the transition from the main oscillator to the timer1 oscillator is shown in figure 2-8. the timer1 oscillator is assumed to be running all the time. after the scs bit is set, the pro- cessor is frozen at the next occurring q1 cycle. after eight synchronization cycles are counted from the timer1 oscillator, operation resumes. no additional delays are required after the synchronization cycles. figure 2-8: timing diagram for transition from osc1 to timer1 oscillator the sequence of events that takes place when switch- ing from the timer1 oscillator to the main oscillator will depend on the mode of the main oscillator. in addition to eight clock cycles of the main oscillator, additional delays may take place. if the main oscillator is configured for an external crys- tal (hs, xt, lp), then the transition will take place after an oscillator startup time (t ost ) has occurred. a timing diagram indicating the transition from the timer1 oscil- lator to the main oscillator for hs, xt and lp modes is shown in figure 2-9. figure 2-9: timing for transition between timer1 and osc1 (hs,xt,lp) q3 q2 q1 q4 q3 q2 osc1 internal scs (osccon<0>) program pc + 2 pc note 1: delay on internal system clock is eight oscillator cycles for synchronization. q1 t1osi q4 q1 pc + 4 q1 ts cs clock counter system q2 q3 q4 q1 t dly t t 1 p t osc 2 1 34 5678 q3 q3 q4 q1 q2 q3 q4 q1 q2 osc1 internal system scs (osccon<0>) program counter pc pc + 2 note 1: t ost = 1024t osc (drawing not to scale). t1osi clock osc2 t ost q1 pc + 6 t t 1 p t osc t scs 1 234 567 8
pic18cxx2 ds39026b-page 20 preliminary ? 7/99 microchip technology inc. if the main oscillator is configured for hs-pll mode, an oscillator startup time (t ost ) plus an additional pll timeout (t pll ) will occur. the pll timeout is typically 2 ms and allows the pll to lock to the main oscillator fre- quency. a timing diagram indicating the transition from the timer1 oscillator to the main oscillator for hs-pll mode is shown in figure 2-10. figure 2-10: timing for transition between timer1 and osc1 (hs with pll) if the main oscillator is configured in the rc, rcio, ec or ecio modes, there is no oscillator startup timeout. operation will resume after eight cycles of the main oscillator have been counted. a timing diagram indicat- ing the transition from the timer1 oscillator to the main oscillator for rc, rcio, ec and ecio modes is shown in figure 2-11. figure 2-11: timing for transition between timer1 and osc1 (rc, ec) q4 q1 q1 q2 q3 q4 q1 q2 osc1 internal system scs (osccon<0>) program counter pc pc + 2 note 1: t ost = 1024t osc (drawing not to scale). t1osi clock t ost q3 pc + 4 t pll t osc t t 1 p t scs q4 osc2 pll clock input 1 2 34 56 78 q3 q4 q1 q1 q2 q3 q4 q1 q2 q3 osc1 internal system scs (osccon<0>) program counter pc pc + 2 note 1: rc oscillator mode assumed. pc + 4 t1osi clock osc2 q4 t t 1 p t osc t scs 1 23 45 6 78
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 21 2.7 effects of sleep mode on the on-chip oscillator when the device executes a sleep instruction, the on- chip clocks and oscillator are turned off and the device is held at the beginning of an instruction cycle (q1 state). with the oscillator off, the osc1 and osc2 sig- nals will stop oscillating. since all the transistor switch- ing currents have been removed, sleep mode achieves the lowest current consumption of the device (only leakage currents). enabling any on-chip feature that will operate during sleep will increase the current con- sumed during sleep. the user can wake from sleep through external reset, watchdog timer reset or through an interrupt. table 2-3: osc1 and osc2 pin states in sleep mode 2.8 power-up delays power up delays are controlled by two timers, so that no external reset circuitry is required for most applications. the delays ensure that the device is kept in reset until the device power supply and clock are stable. for additional information on reset operation, see the reset section. the first timer is the power-up timer (pwrt), which optionally provides a fixed delay of 72 ms (nominal) on power-up only (por and bor). the second timer is the oscillator start-up timer ost, intended to keep the chip in reset until the crystal oscillator is stable. with the pll enabled (hs/pll oscillator mode), the time-out sequence following a power-on reset is differ- ent from other oscillator modes. the time-out sequence is as follows: first the pwrt time-out is invoked after a por time delay has expired. then the oscillator start- up timer (ost) is invoked. however, this is still not a sufficient amount of time to allow the pll to lock at high frequencies. the pwrt timer is used to provide an additional fixed 2ms (nominal) time-out to allow the pll ample time to lock to the incoming clock frequency. osc mode osc1 pin osc2 pin rc floating, external resistor should pull high at logic low rcio floating, external resistor should pull high configured as port a, bit 6 ecio floating configured as port a, bit 6 ec floating at logic low lp, xt, and hs feedback inverter disabled, at quies- cent voltage level feedback inverter disabled, at quies- cent voltage level see table 3-1, in the reset section, for time-outs due to sleep and mclr reset.
pic18cxx2 ds39026b-page 22 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 23 3.0 reset the pic18cxxx differentiates between various kinds of reset: a) power-on reset (por) b) mclr reset during normal operation c) mclr reset during sleep d) watchdog timer (wdt) reset (during normal operation) e) programmable brown-out reset (bor) f) reset instruction g) stack full reset h) stack underflow reset most registers are unaffected by a reset. their status is unknown on por and unchanged by all other resets. the other registers are forced to a reset state on power-on reset, mclr , wdt reset, brown-out reset, m clr reset during sleep and by the reset instruc- tion. most registers are not affected by a wdt wake-up, since this is viewed as the resumption of normal oper- ation. status bits from the rcon register, ri , to , pd , por and bor , are set or cleared differently in different reset situations, as indicated in table 3-2. these bits are used in software to determine the nature of the reset. see table 3-3 for a full description of the reset states of all registers. a simplified block diagram of the on-chip reset circuit is shown in figure 3-1. the enhanced mcu devices have a mclr noise filter in the mclr reset path. the filter will detect and ignore small pulses. a wdt reset does not drive mclr pin low. figure 3-1: simplified block diagram of on-chip reset circuit s r q external reset mclr v dd osc1 wdt module v dd rise detect ost/pwrt on-chip rc osc ( 1 ) wdt time-out power-on reset ost 10-bit ripple counter pwrt chip_reset 10-bit ripple counter reset enable ost ( 2 ) enable pwrt sleep note 1: this is a separate oscillator from the rc oscillator of the clkin pin. 2: see table 3-1 for time-out situations. brown-out reset boren reset instruction stack pointer stack full/underflow reset
pic18cxx2 ds39026b-page 24 preliminary ? 7/99 microchip technology inc. 3.1 power-on reset (por) a power-on reset pulse is generated on-chip when v dd rise is detected. to take advantage of the por cir- cuitry, just tie the mclr pin directly (or through a resis- tor) to v dd . this will eliminate external rc components usually needed to create a power-on reset delay. a maximum rise time for v dd is specified (parameter d004). for a slow rise time, see figure 3-2. when the device starts normal operation (exits the reset condition), device operating parameters (voltage, frequency, temperature,...) must be met to ensure oper- ation. if these conditions are not met, the device must be held in reset until the operating conditions are met. brown-out reset may be used to meet the voltage start-up condition. figure 3-2: external power-on reset circuit (for slow v dd power-up) 3.2 power-up timer (pwrt) the power-up timer provides a fixed nominal time-out (parameter #33) only on power-up from the por. the power-up timer operates on an internal rc oscillator. the chip is kept in reset as long as the pwrt is active. the pwrts time delay allows v dd to rise to an accept- able level. a configuration bit is provided to enable/dis- able the pwrt. the power-up time delay will vary from chip-to-chip due to v dd , temperature and process variation. see dc parameter #33 for details. 3.3 oscillator start-up timer (ost) the oscillator start-up timer (ost) provides 1024 oscillator cycle (from osc1 input) delay after the pwrt delay is over (parameter #32). this ensures that the crystal oscillator or resonator has started and stabi- lized. the ost time-out is invoked only for xt, lp and hs modes and only on power-on reset or wake-up from sleep. 3.4 pll lock timeout with the pll enabled, the timeout sequence following a power-on reset is different from other oscillator modes. a portion of the power-up timer is used to pro- vide a fixed timeout that is sufficient for the pll to lock to the main oscillator frequency. this pll lock timeout (t pll ) is typically 2 ms and follows the oscillator startup timeout (ost). 3.5 brown-out reset (bor) a configuration bit, boren, can disable (if clear/pro- grammed) or enable (if set) the brown-out reset cir- cuitry. if v dd falls below parameter d005 for greater than parameter #35, the brown-out situation will reset the chip. a reset may not occur if v dd falls below parameter d005 for less than parameter #35. the chip will remain in brown-out reset until v dd rises above bv dd . the power-up timer will then be invoked and will keep the chip in reset an additional time delay (parameter #33). if v dd drops below bv dd while the power-up timer is running, the chip will go back into a brown-out reset and the power-up timer will be initial- ized. once v dd rises above bv dd , the power-up timer will execute the additional time delay. note 1: external power-on reset circuit is required only if the v dd power-up slope is too slow. the diode d helps discharge the capacitor quickly when v dd powers down. 2: r < 40 k w is recommended to make sure that the voltage drop across r does not violate the devices electrical specification. 3: r1 = 100 w to 1 k w will limit any current flowing into mclr from external capacitor c in the event of mclr/ v pp pin break- down due to electrostatic discharge (esd) or electrical overstress (eos). c r1 r d v dd mclr pic18cxxx
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 25 3.6 time-out sequence on power-up, the time-out sequence is as follows: first, pwrt time-out is invoked after the por time delay has expired. then, ost is activated. the total time-out will vary based on oscillator configuration and the status of the pwrt. for example, in rc mode with the pwrt disabled, there will be no time-out at all. figure 3-3, figure 3-4, figure 3-5, figure 3-6 and figure 3-7 depict time-out sequences on power-up. since the time-outs occur from the por pulse, if mclr is kept low long enough, the time-outs will expire. bringing mclr high will begin execution immediately (figure 3-5). this is useful for testing purposes or to synchronize more than one pic18cxxx device operat- ing in parallel. table 3-2 shows the reset conditions for some special function registers, while table 3-3 shows the reset conditions for all the registers. table 3-1: time-out in various situations register 3-1: rcon register bits and positions table 3-2: status bits, their significance and the initialization condition for rcon register oscillator configuration power-up (2) brown-out (2) wake-up from sleep or oscillator switch pwrte = 0 pwrte = 1 hs with pll enabled (1) 72 ms + 1024tosc + 2ms 1024tosc + 2 ms 72 ms + 1024tosc + 2ms 1024tosc + 2 ms hs, xt, lp 72 ms + 1024tosc 1024tosc 72 ms + 1024tosc 1024tosc ec 72 ms 72 ms external rc 72 ms 72 ms note 1: 2 ms = nominal time required for the 4x pll to lock. 2: 72 ms is the nominal power-up timer delay r/w-0 r/w-0 u-0 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 ipen lwrt ri to pd por bor bit 7 bit 0 condition program counter rcon register ri to pd por bor stkful stkunf power-on reset 0000h 00-1 1100 1 1 1 0 0 u u mclr reset during normal operation 0000h 00-u uuuu u u u u u u u software reset during normal operation 0000h 0u-0 uuuu 0 u u u u u u stack full reset during normal operation 0000h 0u-u uu11 u u u u u u 1 stack underflow reset during normal operation 0000h 0u-u uu11 u u u u u 1 u mclr reset during sleep 0000h 00-u 10uu u 1 0 u u u u wdt reset 0000h 0u-u 01uu 1 0 1 u u u u wdt wake-up pc + 2 uu-u 00uu u 0 0 u u u u brown-out reset 0000h 0u-1 11u0 1 1 1 1 0 u u interrupt wake-up from sleep pc + 2 ( 1 ) uu-u 00uu u 1 0 u u u u legend: u = unchanged, x = unknown, = unimplemented bit read as '0'. note 1: when the wake-up is due to an interrupt and the gieh or giel bits are set, the pc is loaded with the interrupt vector ( 0x000008h or 0x000018h ).
pic18cxx2 ds39026b-page 26 preliminary ? 7/99 microchip technology inc. table 3-3: initialization conditions for all registers register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets wake-up via wdt or interrupt tosu 242 442 252 452 ---0 0000 ---0 0000 ---0 uuuu (3) tosh 242 442 252 452 0000 0000 0000 0000 uuuu uuuu (3) tosl 242 442 252 452 0000 0000 0000 0000 uuuu uuuu (3) stkptr 242 442 252 452 00-0 0000 00-0 0000 uu-u uuuu (3) pclatu 242 442 252 452 ---0 0000 ---0 0000 ---u uuuu pclath 242 442 252 452 0000 0000 0000 0000 uuuu uuuu pcl 242 442 252 452 0000 0000 0000 0000 pc + 2 (2) tblptru 242 442 252 452 --00 0000 --00 0000 --uu uuuu tblptrh 242 442 252 452 0000 0000 0000 0000 uuuu uuuu tblptrl 242 442 252 452 0000 0000 0000 0000 uuuu uuuu tablat 242 442 252 452 0000 0000 0000 0000 uuuu uuuu prodh 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu prodl 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu intcon 242 442 252 452 0000 000x 0000 000u uuuu uuuu (1) intcon2 242 442 252 452 1111 -1-1 1111 -1-1 uuuu -u-u (1) intcon3 242 442 252 452 11-0 0-00 11-0 0-00 uu-u u-uu (1) indf0 242 442 252 452 n/a n/a n/a postinc0 242 442 252 452 n/a n/a n/a postdec0 242 442 252 452 n/a n/a n/a preinc0 242 442 252 452 n/a n/a n/a plusw0 242 442 252 452 n/a n/a n/a fsr0h 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu fsr0l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu wreg 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu indf1 242 442 252 452 n/a n/a n/a postinc1 242 442 252 452 n/a n/a n/a postdec1 242 442 252 452 n/a n/a n/a preinc1 242 442 252 452 n/a n/a n/a plusw1 242 442 252 452 n/a n/a n/a legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition note 1: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector ( 0008h or 0018h ). 3: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hard- ware stack. 4: see table 3-2 for reset value for specific condition. 5: bit 6 of porta, lata, and trisa are enabled in ecio and rcio oscillator modes only. in all other oscillator modes, they are disabled and read 0. 6: the long write enable is only reset on a por or mclr reset. 7: bit 6 of porta, lata and trisa are not available on all devices. when unimplemented, they are read 0.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 27 fsr1h 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu fsr1l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu bsr 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu indf2 242 442 252 452 n/a n/a n/a postinc2 242 442 252 452 n/a n/a n/a postdec2 242 442 252 452 n/a n/a n/a preinc2 242 442 252 452 n/a n/a n/a plusw2 242 442 252 452 n/a n/a n/a fsr2h 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu fsr2l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu status 242 442 252 452 ---x xxxx ---u uuuu ---u uuuu tmr0h 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu tmr0l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu t0con 242 442 252 452 1111 1111 1111 1111 uuuu uuuu osccon 242 442 252 452 ---- ---0 ---- ---0 ---- ---u lvdcon 242 442 252 452 --00 0101 --00 0101 --uu uuuu wdtcon 242 442 252 452 ---- ---0 ---- ---0 ---- ---u rcon (4, 6) 242 442 252 452 00-1 11q0 00-1 qquu uu-u qquu tmr1h 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu tmr1l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu t1con 242 442 252 452 0-00 0000 u-uu uuuu u-uu uuuu tmr2 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu pr2 242 442 252 452 1111 1111 1111 1111 1111 1111 t2con 242 442 252 452 -000 0000 -000 0000 -uuu uuuu sspbuf 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu sspadd 242 442 252 452 0000 0000 0000 0000 uuuu uuuu sspstat 242 442 252 452 0000 0000 0000 0000 uuuu uuuu sspcon1 242 442 252 452 0000 0000 0000 0000 uuuu uuuu sspcon2 242 442 252 452 0000 0000 0000 0000 uuuu uuuu table 3-3: initialization conditions for all registers (c ont.d) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition note 1: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector ( 0008h or 0018h ). 3: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hard- ware stack. 4: see table 3-2 for reset value for specific condition. 5: bit 6 of porta, lata, and trisa are enabled in ecio and rcio oscillator modes only. in all other oscillator modes, they are disabled and read 0. 6: the long write enable is only reset on a por or mclr reset. 7: bit 6 of porta, lata and trisa are not available on all devices. when unimplemented, they are read 0.
pic18cxx2 ds39026b-page 28 preliminary ? 7/99 microchip technology inc. adresh 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu adresl 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu adcon0 242 442 252 452 0000 0000 0000 0000 uuuu uuuu adcon1 242 442 252 452 --0- 0000 --0- 0000 --u- uuuu ccpr1h 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu ccpr1l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu ccp1con 242 442 252 452 --00 0000 --00 0000 --uu uuuu ccpr2h 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu ccpr2l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu ccp2con 242 442 252 452 --00 0000 --00 0000 --uu uuuu tmr3h 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu tmr3l 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu t3con 242 442 252 452 0000 0000 uuuu uuuu uuuu uuuu spbrg 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu rcreg 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu txreg 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu txsta 242 442 252 452 0000 -01x 0000 -01u uuuu -uuu rcsta 242 442 252 452 0000 000x 0000 000u uuuu uuuu ipr2 242 442 252 452 ---- 1111 ---- 1111 ---- uuuu pir2 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu (1) pie2 242 442 252 452 ---- 0000 ---- 0000 ---- uuuu ipr1 242 442 252 452 1111 1111 1111 1111 uuuu uuuu 242 442 252 452 -111 1111 -111 1111 -uuu uuuu pir1 242 442 252 452 0000 0000 0000 0000 uuuu uuuu (1) 242 442 252 452 -000 0000 -000 0000 -uuu uuuu (1) pie1 242 442 252 452 0000 0000 0000 0000 uuuu uuuu 242 442 252 452 -000 0000 -000 0000 -uuu uuuu table 3-3: initialization conditions for all registers (c ont.d) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition note 1: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector ( 0008h or 0018h ). 3: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hard- ware stack. 4: see table 3-2 for reset value for specific condition. 5: bit 6 of porta, lata, and trisa are enabled in ecio and rcio oscillator modes only. in all other oscillator modes, they are disabled and read 0. 6: the long write enable is only reset on a por or mclr reset. 7: bit 6 of porta, lata and trisa are not available on all devices. when unimplemented, they are read 0.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 29 trise 242 442 252 452 0000 -111 0000 -111 uuuu -uuu trisd 242 442 252 452 1111 1111 1111 1111 uuuu uuuu trisc 242 442 252 452 1111 1111 1111 1111 uuuu uuuu trisb 242 442 252 452 1111 1111 1111 1111 uuuu uuuu trisa (5, 7) 242 442 252 452 -111 1111 (5) -111 1111 (5) -uuu uuuu (5) late 242 442 252 452 ---- -xxx ---- -uuu ---- -uuu latd 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu latc 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu latb 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu lata (5, 7) 242 442 252 452 -xxx xxxx (5) -uuu uuuu (5) -uuu uuuu (5) porte 242 442 252 452 ---- -000 ---- -000 ---- -uuu portd 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu portc 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu portb 242 442 252 452 xxxx xxxx uuuu uuuu uuuu uuuu porta (5, 7) 242 442 252 452 -x0x 0000 (5) -u0u 0000 (5) -uuu uuuu (5) table 3-3: initialization conditions for all registers (c ont.d) register applicable devices power-on reset, brown-out reset mclr resets wdt reset reset instruction stack resets wake-up via wdt or interrupt legend: u = unchanged, x = unknown, - = unimplemented bit, read as '0', q = value depends on condition note 1: one or more bits in the intconx or pirx registers will be affected (to cause wake-up). 2: when the wake-up is due to an interrupt and the giel or gieh bit is set, the pc is loaded with the interrupt vector ( 0008h or 0018h ). 3: when the wake-up is due to an interrupt and the giel or gieh bit is set, the tosu, tosh and tosl are updated with the current value of the pc. the stkptr is modified to point to the next location in the hard- ware stack. 4: see table 3-2 for reset value for specific condition. 5: bit 6 of porta, lata, and trisa are enabled in ecio and rcio oscillator modes only. in all other oscillator modes, they are disabled and read 0. 6: the long write enable is only reset on a por or mclr reset. 7: bit 6 of porta, lata and trisa are not available on all devices. when unimplemented, they are read 0.
pic18cxx2 ds39026b-page 30 preliminary ? 7/99 microchip technology inc. figure 3-3: time-out sequence on power-up (mclr tied to v dd ) figure 3-4: time-out sequence on power-up (mclr not tied to v dd ): case 1 figure 3-5: time-out sequence on power-up (mclr not tied to v dd ): case 2 t pwrt t ost v dd mclr internal por pwrt time-out ost time-out internal reset t pwrt t ost v dd mclr internal por pwrt time-out ost time-out internal reset v dd mclr internal por pwrt time-out ost time-out internal reset t pwrt t ost
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 31 figure 3-6: slow rise time (mclr tied to v dd ) figure 3-7: time-out sequence on por w/ pll enabled (mclr tied to v dd ) v dd mclr internal por pwrt time-out ost time-out internal reset 0v 1v 5v t pwrt t ost t pwrt t ost v dd mclr iinternal por pwrt time-out ost time-out internal reset pll time-out t pll t ost = 1024 clock cycles. t pll ? 2 ms max. first three stages of the pwrt timer.
pic18cxx2 ds39026b-page 32 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 33 4.0 memory organization there are two memory blocks in enhanced mcu devices. these memory blocks are: ? program memory ? data memory each block has its own bus so that concurrent access can occur. 4.1 p rogram memory organization a 21-bit program counter is capable of addressing the 2-mbyte program memory space. accessing a location between the physically implemented memory and the 2-mbyte address will cause a read of all 0s (a nop instruction). pic18c252 and pic18c452 have 32-kbytes of eprom, while pic18c242 and pic18c442 have 16-kbytes of eprom. this means that pic18cx52 devices can store up to 16k of single word instruc- tions, and pic18cx42 devices can store up to 8k of single word instructions. the reset vector address is at 0000h and the interrupt vector addresses are at 0008h and 0018h. figure 4-1 shows the program memory map for pic18c242/442 devices and figure 4-2 shows the program memory map for pic18c252/452 devices.
ds39026b-page 34 preliminary ? 7/99 microchip technology inc. pic18cxx2 figure 4-1: program memory map and stack for pic18c442/ 242 figure 4-2: program memory map and stack for pic18c452/ 252 pc<20:0> stack level 1 stack level 31 reset vector low priority interrupt vector call,bsub,return retfie,retlw 21 0000h 0018h on-chip program memory high priority interrupt vector 0008h user memory space 1fffffh 4000h 3fffh read '0' 200000h pc<20:0> stack level 1 stack level 31 reset vector low priority interrupt vector call,bsub,return retfie,retlw 21 0000h 0018h 8000h 7fffh on-chip program memory high priority interrupt vector 0008h user memory space read '0' 1fffffh 200000h
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 35 4.2 return address stack the return address stack allows any combination of up to 31 program calls and interrupts to occur. the pc (program counter) is pushed onto the stack when a call or rcall instruction is executed or an interrupt is acknowledged. the pc value is pulled off the stack on a return, retlw or a retfie instruction. pclatu and pclath are not affected by any of the return instructions. the stack operates as a 31 word by 21-bit ram and a 5-bit stack pointer, with the stack pointer initialized to 00000b after all resets. there is no ram associated with stack pointer 00000b. this is only a reset value. during a call type instruction causing a push onto the stack, the stack pointer is first incremented and the ram location pointed to by the stack pointer is written with the contents of the pc. during a return type instruction causing a pop from the stack, the contents of the ram location pointed to by the stkptr is trans- ferred to the pc and then the stack pointer is decre- mented. the stack space is not part of either program or data space. the stack pointer is readable and writable, and the address on the top of the stack is readable and writ- able through sfr registers. data can also be pushed to or popped from the stack using the top-of-stack sfrs. status bits indicate if the stack pointer is at or beyond the 31 levels provided. 4.2.1 top-of-stack access the top of the stack is readable and writable. three register locations, tosu, tosh and tosl hold the contents of the stack location pointed to by the stkptr register. this allows users to implement a software stack if necessary. after a call, rcall or interrupt, the software can read the pushed value by reading the tosu, tosh and tosl registers. these values can be placed on a user defined software stack. at return time, the software can replace the tosu, tosh and tosl and do a return. the user must disable the global interrupt enable bits during this time to prevent inadvertent stack operations. 4.2.2 return stack pointer (stkptr) the stkptr register contains the stack pointer value, the stkful (stack full) status bit, and the stkunf (stack underflow) status bits. register 4-1 shows the stkptr register. the value of the stack pointer can be 0 through 31. the stack pointer increments when val- ues are pushed onto the stack and decrements when values are popped off the stack. at reset, the stack pointer value will be 0. the user may read and write the stack pointer value. this feature can be used by a real time operating system for return stack maintenance. after the pc is pushed onto the stack 31 times (without popping any values off the stack), the stkful bit is set. the stkful bit can only be cleared in software or by a por. the action that takes place when the stack becomes full depends on the state of the stvren (stack over- flow reset enable) configuration bit. refer to section 18 for a description of the device configuration bits. if stvren is set (default) the 31st push will push the (pc + 2) value onto the stack, set the stkful bit, and reset the device. the stkful bit will remain set and the stack pointer will be set to 0. if stvren is cleared, the stkful bit will be set on the 31st push and the stack pointer will increment to 31. the 32nd push will overwrite the 31st push (and so on), while stkptr remains at 31. when the stack has been popped enough times to unload the stack, the next pop will return a value of zero to the pc and sets the stkunf bit, while the stack pointer remains at 0. the stkunf bit will remain set until cleared in software or a por occurs. note: returning a value of zero to the pc on an underflow has the effect of vectoring the program to the reset vector, where the stack conditions can be verified and appro- priate actions can be taken.
ds39026b-page 36 preliminary ? 7/99 microchip technology inc. pic18cxx2 register 4-1: stkptr - stack pointer register figure 4-3: return address stack and associated registers 4.2.3 push and pop instructions since the top-of-stack (tos) is readable and writable, the ability to push values onto the stack and pull values off the stack without disturbing normal program execu- tion is a desirable option. to push the current pc value onto the stack, a push instruction can be executed. this will increment the stack pointer and load the cur- rent pc value onto the stack. tosu, tosh and tosl can then be modified to place a return address on the stack. the ability to pull the tos value off of the stack and replace it with the value that was previously pushed onto the stack, without disturbing normal execution, is achieved by using the pop instruction. the pop instruc- tion discards the current tos by decrementing the stack pointer. the previous value pushed onto the stack then becomes the tos value. 4.2.4 stack full/underflow resets these resets are enabled by programming the stvren configuration bit. when the stvren bit is disabled, a full or underflow condition will set the appro- priate stkful or stkunf bit, but not cause a device reset. when the stvren bit is enabled, a full or under- flow will set the appropriate stkful or stkunf bit and then cause a device reset. the stkful or stkunf bits are only cleared by the user software or a por reset. r/c-0 r/c-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 stkful stkunf - sp4 sp3 sp2 sp1 sp0 r = readable bit w = writeable bit c = clearable bit u = unimplemented bit, read as 0 - n = value at por reset bit7 6 5 4 3 2 1 bit0 bit 7 ( 1 ) : stkful : stack full flag bit 1 = stack became full or overflowed 0 = stack has not become full or overflowed bit 6 ( 1 ) : stkunf : stack underflow flag bit 1 = stack underflow occurred 0 = stack underflow did not occur bit 5: unimplemented : read as '0' bit 4-0: sp4:sp0 : stack pointer location bits note 1: bit 7 and bit 6 can only be cleared in user software or by a por. 00011 0x001a34 11111 11110 11101 00010 00001 00000 00010 return address stack top of stack 0x000d58 tosl tosh tosu 0x34 0x1a 0x00 stkptr<4:0>
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 37 4.3 fast register stack a "fast interrupt return" option is available for interrupts. a fast register stack is provided for the status, wreg and bsr registers and are only one in depth. the stack is not readable or writable and is loaded with the current value of the corresponding register when the processor vectors for an interrupt. the values in the registers are then loaded back into the working regis- ters if the fast return instruction is used to return from the interrupt. a low or high priority interrupt source will push values into the stack registers. if both low and high priority interrupts are enabled, the stack registers cannot be used reliably for low priority interrupts. if a high priority interrupt occurs while servicing a low priority interrupt, the stack register valves stored by the low priority inter- rupt will be overwritten. if high priority interrupts are not disabled during low pri- ority interrupts, users must save the key registers in software during a low priority interrupt. if no interrupts are used, the fast register stack can be used to restore the status, wreg and bsr registers at the end of a subroutine call. to use the fast register stack for a subroutine call, a fast call instruction must be executed. example 4-1 shows a source code example that uses the fast register stack. example 4-1: fast register stack code example 4.4 pcl , pclath and pclatu the program counter (pc) specifies the address of the instruction to fetch for execution. the pc is 21-bits wide. the low byte is called the pcl register. this reg- ister is readable and writable. the high byte is called the pch register. this register contains the pc<15:8> bits and is not directly readable or writable. updates to the pch register may be performed through the pclath register. the upper byte is called pcu. this register contains the pc<20:16> bits and is not directly readable or writable. updates to the pcu register may be performed through the pclatu register. the pc addresses bytes in the program memory. to prevent the pc from becoming misaligned with word instructions, the lsb of pcl is fixed to a value of 0. the pc increments by 2 to address sequential instruc- tions in the program memory. the call, rcall, goto and program branch instructions write to the program counter directly. for these instructions, the contents of pclath and pclatu are not transferred to the program counter. the contents of pclath and pclatu will be trans- ferred to the program counter by an operation that writes pcl. similarly, the upper two bytes of the pro- gram counter will be transferred to pclath and pclatu by an operation that reads pcl. this is useful for computed offsets to the pc. (see section 4.8.1) 4.5 clocking scheme/instruction cycle the clock input (from osc1) is internally divided by four to generate four non-overlapping quadrature clocks namely q1, q2, q3 and q4. internally, the pro- gram counter (pc) is incremented every q1, the instruction is fetched from the program memory and latched into the instruction register in q4. the instruc- tion is decoded and executed during the following q1 through q4. the clocks and instruction execution flow is shown in figure 4-4. figure 4-4: clock/instruction cycle call sub1, fast ;status, wreg, bsr ;saved in fast register ;stack sub1 return fast ;restore values saved ;in fast register stack q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 q1 q2 q3 q4 pc osc2/clkout (rc mode) pc pc+2 pc+4 fetch inst (pc) execute inst (pc-2) fetch inst (pc+2) execute inst (pc) fetch inst (pc+4) execute inst (pc+2) internal phase clock
ds39026b-page 38 preliminary ? 7/99 microchip technology inc. pic18cxx2 4.6 instruction flow/pipelining an instruction cycle consists of four q cycles (q1, q2, q3 and q4). the instruction fetch and execute are pipelined such that fetch takes one instruction cycle while decode and execute takes another instruction cycle. however, due to the pipelining, each instruction effectively executes in one cycle. if an instruction causes the program counter to change (e.g. goto ) then two cycles are required to complete the instruction (example 4-2). a fetch cycle begins with the program counter (pc) incrementing in q1. in the execution cycle, the fetched instruction is latched into the instruction register" (ir) in cycle q1. this instruction is then decoded and executed during the q2, q3, and q4 cycles. data memory is read during q2 (operand read) and written during q4 (destination write). example 4-2: instruction pipeline flow 4.7 instructions in program memory the program memory is addressed in bytes. instruc- tions are stored as two bytes or four bytes in program memory. the least significant byte of an instruction word is always stored in a program memory location with an even address (lsb = 0). figure 4-5 shows an example of how instruction words are stored in the pro- gram memory. to maintain alignment with instruction boundaries, the pc increments in steps of 2 and the lsb will always read 0. (see section 4.4) the call and goto instructions have an absolute program memory address embedded into the instruc- tion. since instructions are always stored on word boundaries, the data contained in the instruction is a word address. the word address is written to pc<20:1>, which accesses the desired byte address in program memory. instruction #2 in figure 4-5 shows how the instruction " goto 000006h is encoded in the program memory. program branch instructions which encode a relative address offset operate in the same manner. the offset value stored in a branch instruction represents the number of sin- gle word instructions that the pc will be offset by. section 19.0 provides further details of the instruction set. figure 4-5: instructions in program memory all instructions are single cycle, except for any program branches. these take two cycles since the fetch instruction is flushed from the pipeline while the new instruction is being fetched and then executed. tcy0 tcy1 tcy2 tcy3 tcy4 tcy5 1. movlw 55h fetch 1 execute 1 2. movwf portb fetch 2 execute 2 3. bra sub_1 fetch 3 execute 3 4. bsf porta, bit3 (forced nop) fetch 4 flush 5. instruction @ address sub_1 fetch sub_1 execute sub_1 word address lsb = 1 lsb = 0 program memory byte locations ? 000000h 000002h 000004h 000006h instruction 1: movlw 055h 0fh 55h 000008h instruction 2: goto 000006h efh 03h 00000ah f0h 00h 00000ch instruction 3: movff 123h, 456h c1h 23h 00000eh f4h 56h 000010h 000012h 000014h
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 39 4.7.1 two-word instructions the pic18cxx2 devices have 4 two-word instructions: movff, call, goto and lfsr . the second word of these instructions has the 4 msbs set to 1s and is a special kind of nop instruction. the lower 12 bits of the second word contain data to be used by the instruction. if the first word of the instruction is executed, the data in the second word is accessed. if the second word of the instruction is executed by itself (first word was skipped), it will execute as a nop . this action is neces- sary when the two word instruction is preceded by a conditional instruction that changes the pc. a program example that demonstrates this concept is shown in example 4-3. refer to section 19.0 for further details of the instruction set. example 4-3: two-word instructions 4.8 lookup tables look-up tables are implemented two ways. these are: ? computed goto ?table reads 4.8.1 computed goto a computed goto is accomplished by adding an offset to the program counter ( addwf pcl ). a lookup table can be formed with an addwf pcl instruction and a group of retlw 0xnn instructions. wreg is loaded with an offset into the table before executing a call to that table. the first instruction of the called routine is the addwf pcl instruction. the next instruction executed will be one of the retlw 0xnn instructions that returns the value 0xnn to the calling function. the offset value (value in wreg) specifies the number of bytes that the program counter should advance. in this method, only one data byte may be stored in each instruction location and room on the return address stack is required. 4.8.2 table reads/table writes a better method of storing data in program memory allows 2 bytes of data to be stored in each instruction location. lookup table data may be stored 2 bytes per program word by using table reads and writes. the table pointer (tblptr) specifies the byte address and the table latch (tablat) contains the data that is read from or written to program memory. data is transferred to/from program memory one byte at a time. a description of the table read/table write operation is shown in section 5.0. case 1: object code source code 0110 0110 0000 0000 tstfsz reg1 ; is ram location 0? 1100 0001 0010 0011 movff reg1, reg2 ; no, execute 2-word instruction 1111 0100 0101 0110 ; 2nd operand holds address of reg2 0010 0100 0000 0000 addwf reg3 ; continue code case 2: object code source code 0110 0110 0000 0000 tstfsz reg1 ; is ram location 0? 1100 0001 0010 0011 movff reg1, reg2 ; yes 1111 0100 0101 0110 ; 2nd operand becomes nop 0010 0100 0000 0000 addwf reg3 ; continue code
ds39026b-page 40 preliminary ? 7/99 microchip technology inc. pic18cxx2 4.9 data memory organization the data memory is implemented as static ram. each register in the data memory has a 12-bit address, allowing up to 4096 bytes of data memory. figure 4-6 and figure 4-7 show the data memory organization for the pic18cxx2 devices. banking is required to allow more than 256 bytes to be accessed. the data memory map is divided into as many as 16 banks that contain 256 bytes each. the lower 4 bits of the bank select register (bsr<3:0>) select which bank will be accessed. the upper 4 bits for the bsr are not implemented. the data memory contains special function registers (sfr) and general purpose registers (gpr). the sfrs are used for control and status of the controller and peripheral functions, while gprs are used for data storage and scratch pad operations in the users appli- cation. the sfrs start at the last location of bank 15 (oxfff) and grow downwards. any remaining space beyond the sfrs in the bank may be implemented as gprs. gprs start at the first location of bank 0 and grow upwards. any read of an unimplemented location will read as 0s. the entire data memory may be accessed directly or indirectly. direct addressing may require the use of the bsr register. indirect addressing requires the use of the file select register (fsr). each fsr holds a 12- bit address value that can be used to access any loca- tion in the data memory map without banking. the instruction set and architecture allow operations across all banks. this may be accomplished by indirect addressing or by the use of the movff instruction. the movff instruction is a two word/two cycle instruc- tion that moves a value from one register to another. to ensure that commonly used registers (sfrs and select gprs) can be accessed in a single cycle regard- less of the current bsr values, an access bank is implemented. a segment of bank 0 and a segment of bank 15 comprise the access ram. section 4.10 pro- vides a detailed description of the access ram. 4.9.1 general purpose register file the register file can be accessed either directly or indi- rectly. indirect addressing operates through the file select registers (fsr). the operation of indirect addressing is shown in section 4.12. enhanced mcu devices may have banked memory in the gpr area. gprs are not initialized by a power-on reset and are unchanged on all other resets. data ram is available for use as gpr registers by all instructions. the top half of bank 15 (0xf80 to 0xfff) contains sfrs. all other banks of data memory contain gpr registers starting with bank 0. 4.9.2 special function registers the special function registers (sfrs) are registers used by the cpu and peripheral modules for controlling the desired operation of the device. these registers are implemented as static ram. a list of these registers is given in table 4-1 and table 4-2. the sfrs can be classified into two sets; those asso- ciated with the core function and those related to the peripheral functions. those registers related to the core are described in this section, while those related to the operation of the peripheral features are described in the section of that peripheral feature. the sfrs are typically distributed among the peripher- als whose functions they control. the unused sfr locations will be unimplemented and read as '0's. see table 4-1 for addresses for the sfrs.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 41 figure 4-6: data memory map for pic18c242/442 bank 0 bank 1 bank 14 bank 15 data memory map bsr<3:0> = 0000b = 0001b = 1111b 080h 07fh f80h fffh 00h 7fh 80h ffh access bank when a = 0, the bsr is ignored and the access bank is used. the first 128 bytes are general purpose ram (from bank 0). the second 128 bytes are special function registers (from bank 15). when a = 1, the bsr is used to specify the ram location that the instruction uses. f7fh f00h effh 1ffh 100h 0ffh 000h access ram ffh 00h ffh 00h ffh 00h gpr gpr sfr unused access ram high access ram low bank 2 to 200h unused read 00h = 1110b = 0010b (sfrs)
ds39026b-page 42 preliminary ? 7/99 microchip technology inc. pic18cxx2 figure 4-7: data memory map for pic18c252/452 bank 0 bank 1 bank 14 bank 15 data memory map bsr<3:0> = 0000b = 0001b = 1110b = 1111b 080h 07fh f80h fffh 00h 7fh 80h ffh access bank when a = 0, the bsr is ignored and the access bank is used. the first 128 bytes are general purpose ram (from bank 0). the second 128 bytes are special function registers (from bank 15). when a = 1, the bsr is used to specify the ram location that the instruction uses. bank 4 bank 3 bank 2 f7fh f00h effh 3ffh 300h 2ffh 200h 1ffh 100h 0ffh 000h = 0110b = 0101b = 0011b = 0010b access ram ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h ffh 00h gpr gpr gpr gpr sfr unused access ram high access ram low bank 5 gpr gpr bank 6 to 4ffh 400h 5ffh 500h 600h unused read 00h = 0100b (sfr s)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 43 table 4-1: special function register map fffh tosu fdfh indf2 (3) fbfh ccpr1h f9fh ipr1 ffeh tosh fdeh postinc2 (3) fbeh ccpr1l f9eh pir1 ffdh tosl fddh postdec2 (3) fbdh ccp1con f9dh pie1 ffch stkptr fdch preinc2 (3) fbch ccpr2h f9ch ffbh pclatu fdbh plusw2 (3) fbbh ccpr2l f9bh ffah pclath fdah fsr2h fbah ccp2con f9ah ff9h pcl fd9h fsr2l fb9h f99h ff8h tblptru fd8h status fb8h f98h ff7h tblptrh fd7h tmr0h fb7h f97h ff6h tblptrl fd6h tmr0l fb6h f96h trise (2) ff5h tablat fd5h t0con fb5h f95h trisd (2) ff4h prodh fd4h fb4h f94h trisc ff3h prodl fd3h osccon fb3h tmr3h f93h trisb ff2h intcon fd2h lvdcon fb2h tmr3l f92h trisa ff1h intcon2 fd1h wdtcon fb1h t3con f91h ff0h intcon3 fd0h rcon fb0h f90h fefh indf0 (3) fcfh tmr1h fafh spbrg f8fh feeh postinc0 (3) fceh tmr1l faeh rcreg f8eh fedh postdec0 (3) fcdh t1con fadh txreg f8dh late (2) fech preinc0 (3) fcch tmr2 fach txsta f8ch latd (2) febh plusw0 (3) fcbh pr2 fabh rcsta f8bh latc feah fsr0h fcah t2con faah f8ah latb fe9h fsr0l fc9h sspbuf fa9h f89h lata fe8h wreg fc8h sspadd fa8h f88h fe7h indf1 (3) fc7h sspstat fa7h f87h fe6h postinc1 (3) fc6h sspcon1 fa6h f86h fe5h postdec1 (3) fc5h sspcon2 fa5h f85h fe4h preinc1 (3) fc4h adresh fa4h f84h porte (2) fe3h plusw1 (3) fc3h adresl fa3h f83h portd (2) fe2h fsr1h fc2h adcon0 fa2h ipr2 f82h portc fe1h fsr1l fc1h adcon1 fa1h pir2 f81h portb fe0h bsr fc0h fa0h pie2 f80h porta note 1: unimplemented registers are read as 0 2: this registers is not available on pic18c2x2 devices 3: this is not a physical register
ds39026b-page 44 preliminary ? 7/99 microchip technology inc. pic18cxx2 table 4-2: register file summary filename bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets (note 3) tosu top-of-stack upper byte (tos<20:16>) ---0 0000 ---0 0000 tosh top-of-stack high byte (tos<15:8>) 0000 0000 0000 0000 tosl top-of-stack low byte (tos<7:0>) 0000 0000 0000 0000 stkptr stkful stkunf return stack pointer 00-0 0000 00-0 0000 pclatu holding register for pc<20:16> ---0 0000 ---0 0000 pclath holding register for pc<15:8> 0000 0000 0000 0000 pcl pc low byte (pc<7:0>) 0000 0000 0000 0000 tblptru bit21 (2) program memory table pointer upper byte (tblptr<20:16>) ---0 0000 ---0 0000 tblptrh program memory table pointer high byte (tblptr<15:8>) 0000 0000 0000 0000 tblptrl program memory table pointer low byte (tblptr<7:0>) 0000 0000 0000 0000 tablat program memory table latch 0000 0000 0000 0000 prodh product register high byte xxxx xxxx uuuu uuuu prodl product register low byte xxxx xxxx uuuu uuuu intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u intcon2 rbpu intedg0 intedg1 intedg2 tmr0ip rbip 1111 -1-1 1111 -1-1 intcon3 int2ip int1ip int2ie int1ie int2ifint1if 11-0 0-00 11-0 0-00 indf0 uses contents of fsr0 to address data memory - value of fsr0 not changed (not a physical register) n/a n/a postinc0 uses contents of fsr0 to address data memory - value of fsr0 post-incremented (not a physical register) n/a n/a postdec0 uses contents of fsr0 to address data memory - value of fsr0 post-decremented (not a physical register) n/a n/a preinc0 uses contents of fsr0 to address data memory - value of fsr0 pre-incremented (not a physical register) n/a n/a plusw0 uses contents of fsr0 to address data memory - value of fsr0 pre-incremented (not a physical register) - value of fsr0 offset by value in wreg n/a n/a fsr0h indirect data memory address pointer 0 high byte ---- 0000 ---- 0000 fsr0l indirect data memory address pointer 0 low byte xxxx xxxx uuuu uuuu wreg working register xxxx xxxx uuuu uuuu indf1 uses contents of fsr1 to address data memory - value of fsr1 not changed (not a physical register) n/a n/a postinc1 uses contents of fsr1 to address data memory - value of fsr1 post-incremented (not a physical register) n/a n/a postdec1 uses contents of fsr1 to address data memory - value of fsr1 post-decremented (not a physical register) n/a n/a preinc1 uses contents of fsr1 to address data memory - value of fsr1 pre-incremented (not a physical register) n/a n/a plusw1 uses contents of fsr1 to address data memory - value of fsr1 pre-incremented (not a physical register) - value of fsr1 offset by value in wreg n/a n/a fsr1h indirect data memory address pointer 1 high byte ---- 0000 ---- 0000 fsr1l indirect data memory address pointer 1 low byte xxxx xxxx uuuu uuuu bsr bank select register ---- 0000 ---- 0000 indf2 uses contents of fsr2 to address data memory - value of fsr2 not changed (not a physical register) n/a n/a postinc2 uses contents of fsr2 to address data memory - value of fsr2 post-incremented (not a physical register) n/a n/a postdec2 uses contents of fsr2 to address data memory - value of fsr2 post-decremented (not a physical register) n/a n/a preinc2 uses contents of fsr2 to address data memory - value of fsr2 pre-incremented (not a physical register) n/a n/a plusw2 uses contents of fsr2 to address data memory - value of fsr2 pre-incremented (not a physical register) - value of fsr2 offset by value in wreg n/a n/a fsr2h indirect data memory address pointer 2 high byte ---- 0000 ---- 0000 fsr2l indirect data memory address pointer 2 low byte xxxx xxxx uuuu uuuu status n ov z dc c ---x xxxx ---u uuuu tmr0h timer0 register high byte 0000 0000 0000 0000 tmr0l timer0 register low byte xxxx xxxx uuuu uuuu t0con tmr0on t08bit t0cs t0se psa t0ps2 t0ps1 t0ps0 1111 1111 1111 1111 legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition note 1: ra6 and associated bits are configured as port pins in rcio and ecio oscillator mode only and read '0' in all other oscillator modes. 2: bit 21 of the tblptru allows access to the device configuration bits. 3: other (non-power-up) resets include external reset through mclr and watchdog timer reset.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 45 osccon scs ---- ---0 ---- ---0 lvdcon i rv st lv d e n lv d l 3 lv d l 2 lv d l 1 lv d l 0 --00 0101 --00 0101 wdtcon swdte ---- ---0 ---- ---0 rcon ipen lwrt ri to pd por bor 0q-1 11qq 0q-q qquu tmr1h timer1 register high byte xxxx xxxx uuuu uuuu tmr1l timer1 register low byte xxxx xxxx uuuu uuuu t1con rd16 t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on 0-00 0000 u-uu uuuu tmr2 timer2 register 0000 0000 0000 0000 pr2 timer2 period register 1111 1111 1111 1111 t2con toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 sspbuf ssp receive buffer/transmit register xxxx xxxx uuuu uuuu sspadd ssp address register in i 2 c slave mode. ssp baud rate reload register in i 2 c master mode. 0000 0000 0000 0000 sspstat smp cke d/a psr/w ua bf 0000 0000 0000 0000 sspcon1 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 0000 0000 sspcon2 gcen ackstat ackdt acken rcen pen rsen sen 0000 0000 0000 0000 adresh a/d result register high byte xxxx xxxx uuuu uuuu adresl a/d result register low byte xxxx xxxx uuuu uuuu adcon0 adcs1 adcs0 chs2 chs1 chs0 go/done adon 0000 00-0 0000 00-0 adcon1 adfm adcs2 pcfg3 pcfg2 pcfg1 pcfg0 00-- 0000 00-- 0000 ccpr1h capture/compare/pwm register1 high byte xxxx xxxx uuuu uuuu ccpr1l capture/compare/pwm register1 low byte xxxx xxxx uuuu uuuu ccp1con dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 --00 0000 --00 0000 ccpr2h capture/compare/pwm register2 high byte xxxx xxxx uuuu uuuu ccpr2l capture/compare/pwm register2 low byte xxxx xxxx uuuu uuuu ccp2con dc2b1 dc2b0 ccp2m3 ccp2m2 ccp2m1 ccp2m0 --00 0000 --00 0000 tmr3h timer3 register high byte xxxx xxxx uuuu uuuu tmr3l timer3 register low byte xxxx xxxx uuuu uuuu t3con rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on 0000 0000 uuuu uuuu spbrg usart1 baud rate generator 0000 0000 0000 0000 rcreg usart1 receive register 0000 0000 0000 0000 txreg usart1 transmit register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 rcsta spen rx9 sren cren adden ferr oerr rx9d 0000 000x 0000 000x table 4-2: register file summary (c ont.d) filename bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets (note 3) legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition note 1: ra6 and associated bits are configured as port pins in rcio and ecio oscillator mode only and read '0' in all other oscillator modes. 2: bit 21 of the tblptru allows access to the device configuration bits. 3: other (non-power-up) resets include external reset through mclr and watchdog timer reset.
ds39026b-page 46 preliminary ? 7/99 microchip technology inc. pic18cxx2 4.10 access bank the access bank is an architectural enhancement which is very useful for c compiler code optimization. the techniques used by the c compiler may also be useful for programs written in assembly. this data memory region can be used for: ? intermediate computational values ? local variables of subroutines ? faster context saving/switching of variables ? common variables ? faster evaluation/control of sfrs (no banking) the access bank is comprised of the upper 128 bytes in bank 15 (sfrs) and the lower 128 bytes in bank 0. these two sections will be referred to as access ram high and access ram low, respectively. figure 4-6 and figure 4-7 indicate the access ram areas. a bit in the instruction word specifies if the operation is to occur in the bank specified by the bsr register or in the access bank. this bit is denoted by the a bit (for access bit). when forced in the access bank (a = 0), the last address in access ram low is followed by the first address in access ram high. access ram high maps the special function registers so that these registers can be accessed without any software overhead. this is useful for testing status flags and modifying control bits. ipr2 bclip lvdip tmr3ip ccp2ip ---- 1111 ---- 1111 pir2 bclif lvdif tmr3if ccp2if ---- 0000 ---- 0000 pie2 bclie lvdie tmr3ie ccp2ie ---- 0000 ---- 0000 ipr1 pspip adip rcip txip sspip ccp1ip tmr2ip tmr1ip 1111 1111 1111 1111 pir1 pspif adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 trise ibf obf ibov psp- mode data direction bits for porte 0000 -111 0000 -111 trisd data direction control register for portd 1111 1111 1111 1111 trisc data direction control register for portc 1111 1111 1111 1111 trisb data direction control register for portb 1111 1111 1111 1111 trisa trisa6 (1) data direction control register for porta -111 1111 -111 1111 late read porte data latch, write porte data latch ---- -xxx ---- -uuu latd read portd data latch, write portd data latch xxxx xxxx uuuu uuuu latc read portc data latch, write portc data latch xxxx xxxx uuuu uuuu latb read portb data latch, write portb data latch xxxx xxxx uuuu uuuu lata lata6 (1) read porta data latch, write porta data latch (1) -xxx xxxx -uuu uuuu porte read porte pins, write porte data latch ---- -000 ---- -000 portd read portd pins, write portd data latch xxxx xxxx uuuu uuuu portc read portc pins, write portc data latch xxxx xxxx uuuu uuuu portb read portb pins, write portb data latch xxxx xxxx uuuu uuuu porta ra6 (1) read porta pins, write porta data latch (1) -x0x 0000 -u0u 0000 table 4-2: register file summary (c ont.d) filename bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets (note 3) legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition note 1: ra6 and associated bits are configured as port pins in rcio and ecio oscillator mode only and read '0' in all other oscillator modes. 2: bit 21 of the tblptru allows access to the device configuration bits. 3: other (non-power-up) resets include external reset through mclr and watchdog timer reset.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 47 4.11 b ank select register (bsr) the need for a large general purpose memory space dictates a ram banking scheme. the data memory is partitioned into sixteen banks. when using direct addressing, the bsr should be configured for the desired bank. bsr<3:0> holds the upper 4 bits of the 12-bit ram address. the bsr<7:4> bits will always read 0s, and writes will have no effect. a movlb instruction has been provided in the instruc- tion set to assist in selecting banks. if the currently selected bank is not implemented, any read will return all '0's and all writes are ignored. the status register bits will be set/cleared as appropriate for the instruction performed. each bank extends up to ffh (256 bytes). all data memory is implemented as static ram. a movff instruction ignores the bsr, since the 12-bit addresses are embedded into the instruction word. section 4.12 provides a description of indirect address- ing, which allows linear addressing of the entire ram space. figure 4-8: direct addressing note 1: for register file map detail, see table 4-1. 2: the access bit of the instruction can be used to force an override of the selected bank (bsr<3:0>) to the registers of the access bank. 3: the movff instruction embeds the entire 12-bit address in the instruction. data memory ( 1 ) direct addressing bank select ( 2 ) location select ( 3 ) bsr<3:0> 7 0 from opcode ( 3 ) 00h 01h 0eh 0fh bank 0 bank 1 bank 14 bank 15 1ffh 100h 0ffh 000h effh e00h fffh f00h
ds39026b-page 48 preliminary ? 7/99 microchip technology inc. pic18cxx2 4.12 indirect addressing, indf and fsr registers indirect addressing is a mode of addressing data mem- ory, where the data memory address in the instruction is not fixed. an sfr register is used as a pointer to the data memory location that is to be read or written. since this pointer is in ram, the contents can be mod- ified by the program. this can be useful for data tables in the data memory and for software stacks. figure 4-9 shows the operation of indirect addressing. this shows the moving of the value to the data memory address specified by the value of the fsr register. indirect addressing is possible by using one of the indf registers. any instruction using the indf register actually accesses the register pointed to by the file select register, fsr. reading the indf register itself indirectly (fsr = '0') will read 00h. writing to the indf register indirectly results in a no-operation. the fsr register contains a 12-bit address, which is shown in figure 4-10. the indfn register is not a physical register. address- ing indfn actually addresses the register whose address is contained in the fsrn register (fsrn is a pointer). this is indirect addressing. example 4-4 shows a simple use of indirect addressing to clear the ram in bank1 (locations 100h-1ffh) in a minimum number of instructions. example 4-4: how to clear ram (bank1) using indirect addressing there are three indirect addressing registers. to address the entire data memory space (4096 bytes), these registers are 12-bit wide. to store the 12-bits of addressing information, two 8-bit registers are required. these indirect addressing registers are: 1. fsr0: composed of fsr0h:fsr0l 2. fsr1: composed of fsr1h:fsr1l 3. fsr2: composed of fsr2h:fsr2l in addition, there are registers indf0, indf1 and indf2, which are not physically implemented. reading or writing to these registers activates indirect address- ing, with the value in the corresponding fsr register being the address of the data. if an instruction writes a value to indf0, the value will be written to the address pointed to by fsr0h:fsr0l. a read from indf1 reads the data from the address pointed to by fsr1h:fsr1l. indfn can be used in code anywhere an operand can be used. if indf0, indf1 or indf2 are read indirectly via an fsr, all '0's are read (zero bit is set). similarly, if indf0, indf1 or indf2 are written to indirectly, the operation will be equivalent to a nop instruction and the status bits are not affected. 4.12.1 indirect addressing operation each fsr register has an indf register associated with it, plus four additional register addresses. per- forming an operation on one of these five registers determines how the fsr will be modified during indi- rect addressing. when data access is done to one of the five indfn locations, the address selected will configure the fsrn register to: ? do nothing to fsrn after an indirect access (no change) - indfn ? auto-decrement fsrn after an indirect access (post-decrement) - postdecn ? auto-increment fsrn after an indirect access (post-increment) - postincn ? auto-increment fsrn before an indirect access (pre-increment) - preincn ? use the value in the wreg register as an offset to fsrn. do not modify the value of the wreg or the fsrn register after an indirect access (no change) - pluswn when using the auto-increment or auto-decrement features, the effect on the fsr is not reflected in the status register. for example, if the indirect address causes the fsr to equal '0', the z bit will not be set. incrementing or decrementing an fsr affects all 12 bits. that is, when fsrnl overflows from an increment, fsrnh will be incremented automatically. adding these features allows the fsrn to be used as a stack pointer in addition to its uses for table operations in data memory. each fsr has an address associated with it that per- forms an indexed indirect access. when a data access to this indfn location (pluswn) occurs, the fsrn is configured to add the signed value in the wreg regis- ter and the value in fsr to form the address before an indirect access. the fsr value is not changed. if an fsr register contains a value that points to one of the indfn, an indirect read will read 00h (zero bit is set), while an indirect write will be equivalent to a nop (status bits are not affected). if an indirect addressing operation is done where the target address is an fsrnh or fsrnl register, the write operation will dominate over the pre- or post- increment/decrement functions. lfsr 0x100, fsr0 ; next clrf postinc0 ; clear indf register ; & inc pointer btfss fsr0h, 1 ; all done w/ bank1? goto next ; no, clear next continue ; : ; yes, continue
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 49 figure 4-9: indirect addressing operation figure 4-10: indirect addressing opcode address file address = access of an indirect addressing register fsr instruction executed instruction fetched ram opcode file 12 12 12 bsr<3:0> 8 4 0h fffh note 1: for register file map detail, see table 4-1. data memory ( 1 ) indirect addressing fsr register 11 0 0fffh 0000h location select
ds39026b-page 50 preliminary ? 7/99 microchip technology inc. pic18cxx2 4.13 s tatus register the status register, shown in register 4-2, contains the arithmetic status of the alu. the status register can be the destination for any instruction, as with any other register. if the status register is the destination for an instruction that affects the z, dc, c, ov or n bits, then the write to these five bits is disabled. these bits are set or cleared according to the device logic. there- fore, the result of an instruction with the status regis- ter as destination may be different than intended. for example, clrf status will clear the upper-three bits and set the z bit. this leaves the status register as 000u u1uu (where u = unchanged). it is recommended, therefore, that only bcf, bsf, swapf, movff and movwf instructions are used to alter the status register, because these instruc- tions do not affect the z, c, dc, ov or n bits from the status register. for other instructions not affecting any status bits, see table 19-2. register 4-2: status register note: the c and dc bits operate as a borrow and digit borrow bit respectively, in subtraction. u-0 u-0 u-0 r/w-x r/w-x r/w-x r/w-x r/w-x novzdcc bit 7 bit 0 bit 7:5 unimplemented: read as '0' bit 4 n: negative bit this bit is used for signed arithmatic ( 2s complement). it indicates whether the result was neg- ative, (alu msb = 1) 1 = result was negative 0 = result was positive bit 3 ov: overflow bit this bit is used for signed arithmetic (2s complement). it indicates an overflow of the 7-bit mag- nitude, which causes the sign bit (bit7) to change state. 1 = overflow occurred for signed arithmatic (in this arithmetic operation) 0 = no overflow occurred bit2 z: zero bit 1 = the result of an arithmetic or logic operation is zero 0 = the result of an arithmetic or logic operation is not zero bit 1 dc: digit carry/borrow bit for addwf, addlw, sublw , and subwf instructions 1 = a carry-out from the 4th low order bit of the result occurred 0 = no carry-out from the 4th low order bit of the result note: for borrow , the polarity is reversed. a subtraction is executed by adding the twos complement of the second operand. for rotate ( rrf , rlf ) instructions, this bit is loaded with either the bit 4 or bit 3 of the source register. bit 0 c: carry/borrow bit for addwf, addlw, sublw , and subwf instructions 1 = a carry-out from the most significant bit of the result occurred 0 = no carry-out from the most significant bit of the result occurred note: for borrow , the polarity is reversed. a subtraction is executed by adding the twos complement of the second operand. for rotate ( rrf, rlf ) instructions, this bit is loaded with either the high or low order bit of the source register. legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 51 4.13.1 rcon register the reset control (rcon) register contains flag bits, that allow differentiation between the sources of a device reset. these flags include the to , pd , por , bor and ri bits. this register is readable and writable. register 4-3: rcon register note 1: if the boren configuration bit is set, bor is 1 on power-on reset. if the boren configuration bit is clear, bor is unknown on power-on reset. the bor status bit is a "don't care" and is not necessarily predictable if the brown- out circuit is disabled (the boren config- uration bit is clear). bor must then be set by the user and checked on subsequent resets to see if it is clear, indicating a brown-out has occurred. 2: it is recommended that the por bit be set after a power-on reset has been detected, so that subsequent power-on resets may be detected. r/w-0 r/w-0 u-0 r/w-1 r/w-1 r/w-1 r/w-0 r/w-0 ipen lwrt ri to pd por bor bit 7 bit 0 bit 7 ipen: interrupt priority enable bit 1 = enable priority levels on interrupts 0 = disable priority levels on interrupts (16cxxx compatibility mode) bit 6 lwrt: long write enable bit 1 = enable tblwt to internal program memory once this bit is set, it can only be cleared by a por or mclr reset. 0 = disable tblwt to internal program memory; tblwt only to external program memory bit 5 unimplemented: read as '0' bit 4 ri : reset instruction flag bit 1 = the reset instruction was not executed 0 = the reset instruction was executed causing a device reset (must be set in software after a brown-out reset occurs) bit 3 to : watchdog time-out flag bit 1 = after power-up, clrwdt instruction, or sleep instruction 0 = a wdt time-out occurred bit 2 pd : power-down detection flag bit 1 = after power-up or by the clrwdt instruction 0 = by execution of the sleep instruction bit 1 por : power-on reset status bit 1 = a power-on reset has not occurred 0 = a power-on reset occurred (must be set in software after a power-on reset occurs) bit 0 bor : brown-out reset status bit 1 = a brown-out reset has not occurred 0 = a brown-out reset occurred (must be set in software after a brown-out reset occurs) legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
ds39026b-page 52 preliminary ? 7/99 microchip technology inc. pic18cxx2 notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 53 5.0 table reads/table writes enhanced devices have two memory spaces: the pro- gram memory space and the data memory space. the program memory space is 16 bits wide, while the data memory space is 8 bits wide. table reads and table writes have been provided to move data between these two memory spaces through an 8 bit register (tablat). the operations that allow the processor to move data between the data and program memory spaces are: ?table read ( tblrd ) ? table write ( tblwt ) table read operations retrieve data from program memory and place it into the data memory space. figure 5-1 shows the operation of a table read with program and data memory. table write operations store data from the data mem- ory space into program memory. figure 5-2 shows the operation of a table write with program and data mem- ory. table operations work with byte entities. a table block containing data is not required to be word aligned, so a table block can start and end at any byte address. if a table write is being used to write an executable program to program memory, program instructions will need to be word aligned. figure 5-1: table read operation figure 5-2: table write operation table pointer (1) table latch (8-bit) program memory tblptrh tblptrl ta b l at tblptru instruction: tblrd * note 1: table pointer points to a byte in program memory program memory (tblptr) table pointer (1) table latch (8-bit) program memory tblptrh tblptrl ta b l at program memory (tblptr) tblptru instruction: tblwt * note 1: table pointer points to a byte in program memory
ds39026b-page 54 preliminary ? 7/99 microchip technology inc. pic18cxx2 5.1 c ontrol registers several control registers are used in conjunction with the tblrd and tblwt instructions. these include the: ? tblptr registers ? tablat register ? rcon register 5.1.1 rcon register the lwrt bit specifies the operation of table writes to internal memory when the v pp voltage is applied to the mclr pin. when the lwrt bit is set, the controller continues to execute user code, but long table writes are allowed (for programming internal program mem- ory) from user mode. the lwrt bit can be cleared only by performing either a por or mclr reset. register 5-1: rcon register (address: 08h) r/w-0 r/w-0 u-0 r/w-1 r/w-1 r/w-1 r/w-0 r/w-0 ipen lwrt ri to pd por bor bit 7 bit 0 bit 7 ipen: interrupt priority enable 1 = enable priority levels on interrupts 0 = disable priority levels on interrupts (16cxxx compatibility mode) bit 6 lwrt: long write enable 1 = enable tblwt to internal program memory 0 = disable tblwt to internal program memory. note 1: only cleared on a por or mclr reset. this bit has no effect on tblwts to external program memory. bit 5 unimplemented : read as '0' bit 4 ri : reset instruction flag bit 1 = no reset instruction occurred 0 = a reset instruction occurred bit 3 to : time-out bit 1 = after power-up, clrwdt instruction, or sleep instruction 0 = a wdt time-out occurred bit 2 pd : power-down bit 1 = after power-up or by the clrwdt instruction 0 = by execution of the sleep instruction bit 1 por : power-on reset status bit 1 = no power-on reset occurred 0 = a power-on reset occurred (must be set in software after a power-on reset occurs) bit 0 bor : brown-out reset status bit 1 = no brown-out reset nor por reset occurred 0 = a brown-out reset nor por reset occurred (must be set in software after a brown-out reset occurs) legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 55 5.1.2 tablat - table latch register the table latch (tablat) is an 8-bit register mapped into the sfr space. the table latch is used to hold 8-bit data during data transfers between program memory and data memory. 5.1.3 tblptr - table pointer register the table pointer (tblptr) addresses a byte within the program memory. the tblptr is comprised of three sfr registers (table pointer upper byte, high byte and low byte). these three registers (tblp- tru:tblptrh:tblptrl) join to form a 22-bit wide pointer. the low order 21-bits allow the device to address up to 2m bytes of program memory space. the 22nd bit allows access to the device id, the user id and the configuration bits. the table pointer tblptr is used by the tblrd and tblwt instructions. these instructions can update the tblptr in one of four ways based on the table operation. these operations are shown in table 5-1. these operations on the tblptr only affect the low order 21-bits. table 5-1: table pointer operations with tblrd and tblwt instructions example operation on table pointer tblrd* tblwt* tblptr is not modified tblrd*+ tblwt*+ tblptr is incremented after the read/write tblrd*- tblwt*- tblptr is decremented after the read/write tblrd+* tblwt+* tblptr is incremented before the read/write
ds39026b-page 56 preliminary ? 7/99 microchip technology inc. pic18cxx2 5.2 internal program memory read/ writes 5.2.1 table read overview (tblrd) the tblrd instructions are used to read data from pro- gram memory to data memory. tblptr points to a byte address in program space. executing tblrd places the byte pointed to into tab- lat. in addition, tblptr can be modified automati- cally for the next table read operation. table reads from program memory are performed one byte at a time. the instruction will load tablat with the one byte from program memory pointed to by tblptr. 5.2.2 internal program memory write block size the internal program memory of pic18cxxx devices is written in blocks. for pic18cxx2 devices, the write block size is 2 bytes. consequently, table write oper- ations to internal program memory are performed in pairs, one byte at a time. when a table write occurs to an even program mem- ory address (tblptr<0> = 0), the contents of tablat are transferred to an internal holding register. this is performed as a short write and the program memory block is not actually programmed at this time. the hold- ing register is not accessible by the user. when a table write occurs to an odd program memory address (tblptr,)>=1), a long write is started. during the long write, the contents of tablat are written to the high byte of the program memory block and the con- tents of the holding register are transferred to the low byte of the program memory block. figure 5-3 shows the holding register and the program memory write blocks. if a single byte is to be programmed, the low (even) byte of the destination program word should be read using tblrd *, modified or changed, if required, and written back to the same address using tblwt*+ . the high (odd) byte should be read using tblrd* , modified or changed if required, and written back to the same address using tblwt . the write to an odd address will cause a long write to begin. this process ensures that existing data in either byte will not be changed unless desired. figure 5-3: holding register and the write block block n block n + 1 block n + 2 msb the write to the msb of the write block causes the entire block to be written to pro- gram memory. the program memory block that is written depends on the address that is written to in the msb of the write block. holding register program memory (x 2-bits) write block
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 57 5.2.2.1 operation the long write is what actually programs words of data into the internal memory. when a tblwt to the msb of the write block occurs, instruction execution is halted. during this time, programming voltage and the data stored in internal latches is applied to program memory. for a long write to occur: 1. mclr /v pp pin must be at the programming volt- age 2. lwrt bit must be set 3. tblwt to the address of the msb of the write block if the lwrt bit is clear, a short write will occur and pro- gram memory will not be changed. if the tblwt is not to the msb of the write block, then the programming phase is not initiated. setting the lwrt bit enables long writes when the mclr pin is taken to v pp voltage. once the lwrt bit is set, it can be cleared only by performing a por or mclr reset. to ensure that the memory location has been well pro- grammed, a minimum programming time is required. the long write can be terminated after the program- ming time has expired by a reset or an interrupt. having only one interrupt source enabled to terminate the long write ensures that no unintended interrupts will prema- turely terminate the long write. 5.2.2.2 sequence of events the sequence of events for programming an internal program memory location should be: 1. enable the interrupt that terminates the long write. disable all other interrupts. 2. clear the source interrupt flag. 3. if interrupt service routine execution is desired when the device wakes, enable global inter- rupts. 4. set lwrt bit in the rcon register. 5. raise mclr /v pp pin to the programming volt- age, v pp . 6. clear the wdt (if enabled). 7. set the interrupt source to interrupt at the required time. 8. execute the table write for the lower (even) byte. this will be a short write. 9. execute the table write for the upper (odd) byte. this will be a long write. the controller will go to sleep while programming. the interrupt wakes the controller. 10. if gie was set, service the interrupt request. 11. lower mclr /v pp pin to v dd . 12. verify the memory location (table read).
ds39026b-page 58 preliminary ? 7/99 microchip technology inc. pic18cxx2 5.2.3 interrupts the long write must be terminated by a reset or any interrupt. the interrupt source must have its interrupt enable bit set. when the source sets its interrupt flag, program- ming will terminate. this will occur regardless of the settings of interrupt priority bits, the gie/gieh bit or the pie/giel bit. depending on the states of interrupt priority bits, the gie/gieh bit or the pie/giel bit, program execution can either be vectored to the high or low priority inter- rupt service routine (isr) or continue execution from where programming commenced. in either case, the interrupt flag will not be cleared when programming is terminated and will need to be cleared by the software. table 5-2: sleep mode, interrupt enable bits and interrupt results gie/ gieh pie/ giel priority interrupt enable interrupt flag action xx x 0 (default) x long write continues even if interrupt flag becomes set during sleep. x x x 1 0 long write continues, will wake when the interrupt flag is set. 0 (default) 0 (default) x 1 1 terminates long write, executes next instruction. interrupt flag not cleared. 0 (default) 11 high priority (default) 1 1 terminates long write, executes next instruction. interrupt flag not cleared. 10 (default) 0 low 1 1 terminates long write, executes next instruction. interrupt flag not cleared. 0 (default) 10 low 1 1 terminates long write, branches to low priority interrupt vector. interrupt flag can be cleared by isr. 10 (default) 1 high priority (default) 1 1 terminates long write, branches to high priority interrupt vector. interrupt flag can be cleared by isr.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 59 5.2.4 unexpected termination of write operations if a write is terminated by an unplanned event such as loss of power, an unexpected reset, or an interrupt that was not disabled, the memory location just pro- grammed should be verified and reprogrammed if needed.
ds39026b-page 60 preliminary ? 7/99 microchip technology inc. pic18cxx2 notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 61 6.0 8 x 8 hardware multiplier 6.1 i ntroduction an 8 x 8 hardware multiplier is included in the alu of the pic18cxx2 devices. by making the multiply a hardware operation, it completes in a single instruction cycle. this is an unsigned multiply that gives a 16-bit result. the result is stored into the 16-bit product regis- ter pair (prodh:prodl). the multiplier does not affect any flags in the alusta register. making the 8 x 8 multiplier execute in a single cycle gives the following advantages: ? higher computational throughput ? reduces code size requirements for multiply algo- rithms the performance increase allows the device to be used in applications previously reserved for digital signal processors. table 6-1 shows a performance comparison between enhanced devices using the single cycle hardware mul- tiply, and performing the same function without the hardware multiply. table 6-1: performance comparison routine multiply method program memory (words) cycles (max) time @ 40 mhz @ 10 mhz @ 4 mhz 8 x 8 unsigned without hardware multiply 13 69 6.9 m s27.6 m s69 m s hardware multiply 1 1 100 ns 400 ns 1 m s 8 x 8 signed without hardware multiply 33 91 9.1 m s36.4 m s91 m s hardware multiply 6 6 600 ns 2.4 m s6 m s 16 x 16 unsigned without hardware multiply 21 242 24.2 m s96.8 m s242 m s hardware multiply 24 24 2.4 m s9.6 m s24 m s 16 x 16 signed without hardware multiply 52 254 25.4 m s 102.6 m s254 m s hardware multiply 36 36 3.6 m s14.4 m s36 m s
pic18cxx2 ds39026b-page 62 preliminary ? 7/99 microchip technology inc. 6.2 o peration example 6-1 shows the sequence to do an 8 x 8 unsigned multiply. only one instruction is required when one argument of the multiply is already loaded in the wreg register. example 6-2 shows the sequence to do an 8 x 8 signed multiply. to account for the sign bits of the arguments, each arguments most significant bit (msb) is tested and the appropriate subtractions are done. example 6-1: 8 x 8 unsigned multiply routine example 6-2: 8 x 8 signed multiply routine example 6-3 shows the sequence to do a 16 x 16 unsigned multiply. equation 6-1 shows the algorithm that is used. the 32-bit result is stored in 4 registers res3:res0. equation 6-1: 16 x 16 unsigned multiplication algorithm res3:res0 = arg1h:arg1l arg2h:arg2l = (arg1h arg2h 2 16 )+ (arg1h arg2l 2 8 )+ (arg1l arg2h 2 8 )+ (arg1l arg2l) example 6-3: 16 x 16 unsigned multiply routine example 6-4 shows the sequence to do an 16 x 16 signed multiply. equation 6-2 shows the algorithm used. the 32-bit result is stored in four registers res3:res0. to account for the sign bits of the argu- ments, each argument pairs most significant bit (msb) is tested and the appropriate subtractions are done. equation 6-2: 16 x 16 signed multiplication algorithm res3:res0 = arg1h:arg1l arg2h:arg2l = (arg1h arg2h 2 16 )+ (arg1h arg2l 2 8 )+ (arg1l arg2h 2 8 )+ (arg1l arg2l)+ (-1 arg2h<7> arg1h:arg1l 2 16 )+ (-1 arg1h<7> arg2h:arg2l 2 16 ) movff arg1, wreg ; mulwf arg2 ; arg1 * arg2 -> ; prodh:prodl movff arg1, wreg mulwf arg2 ; arg1 * arg2 -> ; prodh:prodl btfsc arg2, sb ; test sign bit subwf prodh, f ; prodh = prodh ; - arg1 movff arg2, wreg btfsc arg1, sb ; test sign bit subwf prodh, f ; prodh = prodh ; - arg2 movff arg1l, wreg mulwf arg2l ; arg1l * arg2l -> ; prodh:prodl movff prodh, res1 ; movff prodl, res0 ; ; movff arg1h, wreg mulwf arg2h ; arg1h * arg2h -> ; prodh:prodl movff prodh, res3 ; movff prodl, res2 ; ; movff arg1l, wreg mulwf arg2h ; arg1l * arg2h -> ; prodh:prodl movff prodl, wreg ; addwf res1, f ; add cross movff prodh, wreg ; products addwfc res2, f ; clrf wreg, f ; addwfc res3, f ; ; movff arg1h, wreg ; mulwf arg2l ; arg1h * arg2l -> ; prodh:prodl movff prodl, wreg ; addwf res1, f ; add cross movff prodh, wreg ; products addwfc res2, f ; clrf wreg, f ; addwfc res3, f ;
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 63 example 6-4: 16 x 16 signed multiply routine movff arg1l, wreg mulwf arg2l ; arg1l * arg2l -> ; prodh:prodl movff prodh, res1 ; movff prodl, res0 ; ; movff arg1h, wreg mulwf arg2h ; arg1h * arg2h -> ; prodh:prodl movff prodh, res3 ; movff prodl, res2 ; ; movff arg1l, wreg mulwf arg2h ; arg1l * arg2h -> ; prodh:prodl movff prodl, wreg ; addwf res1, f ; add cross movff prodh, wreg ; products addwfc res2, f ; clrf wreg, f ; addwfc res3, f ; ; movff arg1h, wreg ; mulwf arg2l ; arg1h * arg2l -> ; prodh:prodl movff prodl, wreg ; addwf res1, f ; add cross movff prodh, wreg ; products addwfc res2, f ; clrf wreg, f ; addwfc res3, f ; ; btfss arg2h, 7 ; arg2h:arg2l neg? goto sign_arg1 ; no, check arg1 movff arg1l, wreg ; subwf res2 ; movff arg1h, wreg ; subwfb res3 ; sign_arg1 btfss arg1h, 7 ; arg1h:arg1l neg? goto cont_code ; no, done movff arg2l, wreg ; subwf res2 ; movff arg2h, wreg ; subwfb res3 ; cont_code :
pic18cxx2 ds39026b-page 64 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 65 7.0 interrupts the pic18cxx2 devices have multiple interrupt sources and an interrupt priority feature that allows each interrupt source to be assigned a high priority level or a low priority level. the high priority interrupt vector is at 000008h and the low priority interrupt vector is at 000018h. high priority interrupt events will over- ride any low priority interrupts that may be in progress. there are ten registers which are used to control inter- rupt operation. these registers are: ? rcon ?intcon ? intcon2 ? intcon3 ? pir1, pir2 ? pie1, pie2 ? ipr1, ipr2 it is recommended that the microchip header files sup- plied with mplab be used for the symbolic bit names in these registers. this allows the assembler/compiler to automatically take care of the placement of these bits within the specified register. each interrupt source has three bits to control its oper- ation. the functions of these bits are: ? flag bit to indicate that an interrupt event occurred ? enable bit that allows program execution to branch to the interrupt vector address when the flag bit is set ? priority bit to select high priority or low priority the interrupt priority feature is enabled by setting the ipen bit (rcon<7>). when interrupt priority is enabled, there are two bits which enable interrupts glo- bally. setting the gieh bit (intcon<7>) enables all interrupts that have the priority bit set. setting the giel bit (intcon<6>) enables all interrupts that have the priority bit cleared. when the interrupt flag, enable bit and appropriate global interrupt enable it are set, the interrupt will vector immediately to address 000008h or 000018h depending on the priority level. individual interrupts can be disabled through their corresponding enable bits. when the ipen bit is cleared (default state), the inter- rupt priority feature is disabled and interrupts are com- patible with picmicro mid-range devices. in compatibility mode, the interrupt priority bits for each source have no effect. intcon<6> is the peie bit, which enables/disables all peripheral interrupt sources. intcon<7> is the gie bit, which enables/disables all interrupt sources. all interrupts branch to address 000008h in compatibility mode. when an interrupt is responded to, the global interrupt enable bit is cleared to disable further interrupts. if the ipen bit is cleared, this is the gie bit. if interrupt prior- ity levels are used, this will be either the gieh or giel bit. high priority interrupt sources can interrupt a low priority interrupt. the return address is pushed onto the stack and the pc is loaded with the interrupt vector address (000008h or 000018h). once in the interrupt service routine, the source(s) of the interrupt can be deter- mined by polling the interrupt flag bits. the interrupt flag bits must be cleared in software before re-enabling interrupts to avoid recursive interrupts. the "return from interrupt" instruction, retfie, exits the interrupt routine and sets the gie bit (gieh or giel if priority levels are used), which re-enables interrupts. for external interrupt events, such as the int pins or the portb input change interrupt, the interrupt latency will be three to four instruction cycles. the exact latency is the same for one or two cycle instructions. individual interrupt flag bits are set regardless of the status of their corresponding enable bit or the gie bit.
pic18cxx2 ds39026b-page 66 preliminary ? 7/99 microchip technology inc. figure 7-1: interrupt logic t0ie gieh/gie giel/peie wake-up if in sleep mode interrupt to cpu vector to location 0008h int2f int2e int2p int1f int1e int1p t0if t0ie t0ip int0f int0e rbif rbie rbip ipe t0if t0ip int1f int1e int1p int2f int2e int2p rbif rbie rbip int0f int0e giel\peie interrupt to cpu vector to location ipe ipe 0018h peripheral interrupt flag bit peripheral interrupt enable bit peripheral interrupt priority bit peripheral interrupt flag bit peripheral interrupt enable bit peripheral interrupt priority bit tmr1if tmr1ie tmr1ip xxxxif xxxxie xxxxip additional peripheral interrupts tmr1if tmr1ie tmr1ip high priority interrupt generation low priority interrupt generation xxxxif xxxxie xxxxip additional peripheral interrupts
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 67 7.0.1 intcon registers the intcon registers are readable and writable registers, which contains various enable, priority and flag bits. register 7-1: intcon register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-x gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif bit 7 bit 0 bit 7 gie/gieh: global interrupt enable bit when ipen = 0: 1 = enables all un-masked interrupts 0 = disables all interrupts when ipen = 1: 1 = enables all interrupts 0 = disables all interrupts bit 6 peie/geil: peripheral interrupt enable bit when ipen = 0: 1 = enables all un-masked peripheral interrupts 0 = disables all peripheral interrupts when ipen = 1: 1 = enables all low priority peripheral interrupts 0 = disables all priority peripheral interrupts bit 5 tmr0ie: tmr0 overflow interrupt enable bit 1 = enables the tmr0 overflow interrupt 0 = disables the tmr0 overflow interrupt bit 4 int0ie: int0 external interrupt enable bit 1 = enables the int0 external interrupt 0 = disables the int0 external interrupt bit 3 rbie: rb port change interrupt enable bit 1 = enables the rb port change interrupt 0 = disables the rb port change interrupt bit 2 tmr0if: tmr0 overflow interrupt flag bit 1 = tmr0 register has overflowed (must be cleared in software) 0 = tmr0 register did not overflow bit 1 int0if: int0 external interrupt flag bit 1 = the int0 external interrupt occurred (must be cleared in software) 0 = the int0 external interrupt did not occur bit 0 rbif: rb port change interrupt flag bit 1 = at least one of the rb7:rb4 pins changed state (must be cleared in software) 0 = none of the rb7:rb4 pins have changed state legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown note: interrupt flag bits get set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit. user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. this feature allows for software polling.
pic18cxx2 ds39026b-page 68 preliminary ? 7/99 microchip technology inc. register 7-2: intcon2 register r/w-1 r/w-1 r/w-1 r/w-1 u-0 r/w-1 u-0 r/w-1 rbpu intedg0 intedg1 intedg2 tmr0ip rbip bit 7 bit 0 bit 7 rbpu : portb pull-up enable bit 1 = all portb pull-ups are disabled 0 = portb pull-ups are enabled by individual port latch values bit 6 intedg0 :external interrupt0 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 5 intedg1 : external interrupt1 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 4 intedg2 : external interrupt2 edge select bit 1 = interrupt on rising edge 0 = interrupt on falling edge bit 3 unimplemented: read as '0' bit 2 tmr0ip : tmr0 overflow interrupt priority bit 1 = high priority 0 = low priority bit 1 unimplemented: read as '0' bit 0 rbip : rb port change interrupt priority bit 1 = high priority 0 = low priority legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown note: interrupt flag bits get set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit. user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. this feature allows for software polling.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 69 register 7-3: intcon3 register r/w-1 r/w-1 u-0 r/w-0 r/w-0 u-0 r/w-0 r/w-0 int2ip int1ip int2ie int1ie int2if int1if bit 7 bit 0 bit 7 int2ip: int2 external interrupt priority bit 1 =high priority 0 =low priority bit 6 int1ip: int1 external interrupt priority bit 1 =high priority 0 =low priority bit 5 unimplemented: read as '0' bit 4 int2ie: int2 external interrupt enable bit 1 =enables the int2 external interrupt 0 =disables the int2 external interrupt bit 3 int1ie: int1 external interrupt enable bit 1 =enables the int1 external interrupt 0 =disables the int1 external interrupt bit 2 unimplemented: read as '0' bit 1 int2if: int2 external interrupt flag bit 1 =the int2 external interrupt occurred (must be cleared in software) 0 =the int2 external interrupt did not occur bit 0 int1if: int1 external interrupt flag bit 1 =the int1 external interrupt occurred (must be cleared in software) 0 =the int1 external interrupt did not occur legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown note: interrupt flag bits get set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit. user software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. this feature allows for software polling.
pic18cxx2 ds39026b-page 70 preliminary ? 7/99 microchip technology inc. 7.0.2 pir registers the pir registers contain the individual flag bits for the peripheral interrupts. due to he number of peripheral interrupt sources, there are two peripheral interrupt flag registers (pir1, pir2). 7.0.3 pie registers the pie registers contain the individual enable bits for the peripheral interrupts. due to the number of periph- eral interrupt sources, there are two peripheral inter- rupt enable registers (pie1, pie2). when ipen = 0, the peie bit must be set to enable any of these periph- eral interrupts. 7.0.4 ipr registers the ipr registers contain the individual priority bits for the peripheral interrupts. due to on the number of peripheral interrupt sources, there are two peripheral interrupt priority registers (ipr1, ipr2). the operation of the priority bits requires that the interrupt priority enable (ipen) bit be set. 7.0.5 rcon register the rcon register contains the bit which is used to enable prioritized interrupts (ipen). register 7-4: rcon register note 1: interrupt flag bits get set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the global enable bit, gie (intcon<7>). note 2: user software should ensure the appropri- ate interrupt flag bits are cleared prior to enabling an interrupt, and after servicing that interrupt. r/w-0 r/w-0 u-0 r/w-1 r/w-1 r/w-1 r/w-0 r/w-0 ipen lwrt ri to pd por bor bit 7 bit 0 bit 7 ipen: interrupt priority enable bit 1 = enable priority levels on interrupts 0 = disable priority levels on interrupts (16cxxx compatibility mode) bit 6 lwrt: long write enable for details of bit operation see register 4-1 bit 5 unimplemented: read as '0' bit 4 ri : reset instruction flag bit for details of bit operation see register 4-1 bit 3 to : watchdog time-out flag bit for details of bit operation see register 4-1 bit 2 pd : power-down detection flag bit for details of bit operation see register 4-1 bit 1 por : power-on reset status bit for details of bit operation see register 4-1 bit 0 bor : brown-out reset status bit for details of bit operation see register 4-1 legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 71 register 7-5: peripheral interrupt request (flag) registers r/w-0 r/w-0 r-0 r-0 r/w-0 r/w-0 r/w-0 r/w-0 pir1 pspif adif rcif txif sspif ccp1if tmr2if tmr1if bit 7 bit 0 u-0 u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 pir2 bclif lvdif tmr3if ccp2if bit 7 bit 0 pir1 bit 7 pspif: parallel slave port read/write interrupt flag bit 1 = a read or a write operation has taken place (must be cleared in software) 0 = no read or write has occurred bit 6 adif : a/d converter interrupt flag bit 1 = an a/d conversion completed (must be cleared in software) 0 = the a/d conversion is not complete bit 5 rcif : usart receive interrupt flag bit 1 = the usart receive buffer, rcreg, is full (cleared when rcreg is read) 0 = the usart receive buffer is empty bit 4 txif : usart transmit interrupt flag bit 1 = the usart transmit buffer, txreg, is empty (cleared when txreg is written) 0 = the usart transmit buffer is full bit 3 sspif : master synchronous serial port interrupt flag bit 1 = the transmission/reception is complete (must be cleared in software) 0 = waiting to transmit/receive bit 2 ccp1if : ccp1 interrupt flag bit capture mode 1 = a tmr1 register capture occurred (must be cleared in software) 0 = no tmr1 register capture occurred compare mode 1 = a tmr1 register compare match occurred (must be cleared in software) 0 = no tmr1 register compare match occurred pwm mode unused in this mode bit 1 tmr2if: tmr2 to pr2 match interrupt flag bit 1 = tmr2 to pr2 match occurred (must be cleared in software) 0 = no tmr2 to pr2 match occurred bit 0 tmr1if: tmr1 overflow interrupt flag bit 1 = tmr1 register overflowed (must be cleared in software) 0 = tmr1 register did not overflow
pic18cxx2 ds39026b-page 72 preliminary ? 7/99 microchip technology inc. register 7-5: peripheral interrupt request (flag) registers (contd) pir2 bit 7-4 unimplemented: read as '0' bit 3 bclif : bus collision interrupt flag bit 1 = a bus collision occurred (must be cleared in software) 0 = no bus collision occurred bit 2 lv d i f : low-voltage detect interrupt flag bit 1 = a low voltage condition occurred (must be cleared in software) 0 = the device voltage is above the low voltage detect trip point bit 1 tmr3if : tmr3 overflow interrupt flag bit 1 = tmr3 register overflowed (must be cleared in software) 0 = tmr3 register did not overflow bit 0 ccp2if : ccpx interrupt flag bit capture mode 1 = a tmr1 register capture occurred (must be cleared in software) 0 = no tmr1 register capture occurred compare mode 1 = a tmr1 register compare match occurred (must be cleared in software) 0 = no tmr1 register compare match occurred pwm mode unused in this mode legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 73 register 7-6: peripheral interrupt enable registers r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 pie1 pspie adie rcie txie sspie ccp1ie tmr2ie tmr1ie bit 7 bit 0 u-0 u-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 pie2 bclie lvdie tmr3ie ccp2ie bit 7 bit 0 pie1 bit 7 pspie: parallel slave port read/write interrupt enable bit 1 = enables the psp read/write interrupt 0 = disables the psp read/write interrupt bit 6 adie : a/d converter interrupt enable bit 1 = enables the a/d interrupt 0 = disables the a/d interrupt bit 5 rcie : usart receive interrupt enable bit 1 = enables the usart receive interrupt 0 = disables the usart receive interrupt bit 4 txie : usart transmit interrupt enable bit 1 = enables the usart transmit interrupt 0 = disables the usart transmit interrupt bit 3 sspie : master synchronous serial port interrupt enable bit 1 = enables the mssp interrupt 0 = disables the mssp interrupt bit 2 ccp1ie : ccp1 interrupt enable bit 1 = enables the ccp1 interrupt 0 = disables the ccp1 interrupt bit 1 tmr2ie : tmr2 to pr2 match interrupt enable bit 1 = enables the tmr2 to pr2 match interrupt 0 = disables the tmr2 to pr2 match interrupt bit 0 tmr1ie : tmr1 overflow interrupt enable bit 1 = enables the tmr1 overflow interrupt 0 = disables the tmr1 overflow interrupt pie2 bit 7-4 unimplemented: read as '0' bit 3 bclie : bus collision interrupt enable bit 1 = enabled 0 = disabled bit 2 lv d i e : low-voltage detect interrupt enable bit 1 = enabled 0 = disabled bit 1 tmr3ie : tmr3 overflow interrupt enable bit 1 = enables the tmr3 overflow interrupt 0 = disables the tmr3 overflow interrupt bit 0 ccp2ie : ccp2 interrupt enable bit 1 = enables the ccp2 interrupt 0 = disables the ccp2 interrupt legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 74 preliminary ? 7/99 microchip technology inc. register 7-7: peripheral interrupt priority registers r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 ipr1 pspip adip rcip txip sspip ccp1ip tmr2ip tmr1ip bit 7 bit 0 u-0 u-0 u-0 u-0 r/w-1 r/w-1 r/w-1 r/w-1 ipr2 bclip lvdip tmr3ip ccp2ip bit 7 bit 0 ipr1 bit 7 pspip: parallel slave port read/write interrupt priority bit 1 = high priority 0 = low priority bit 6 adip : a/d converter interrupt priority bit 1 = high priority 0 = low priority bit 5 rcip : usart receive interrupt priority bit 1 = high priority 0 = low priority bit 4 txip : usart transmit interrupt priority bit 1 = high priority 0 = low priority bit 3 sspip : master synchronous serial port interrupt priority bit 1 = high priority 0 = low priority bit 2 ccp1ip : ccp1 interrupt priority bit 1 = high priority 0 = low priority bit 1 tmr2ip : tmr2 to pr2 match interrupt priority bit 1 = high priority 0 = low priority bit 0 tmr1ip : tmr1 overflow interrupt priority bit 1 = high priority 0 = low priority ipr2 bit 7-4 unimplemented: read as '0' bit 3 bclip : bus collision interrupt priority bit 1 = high priority 0 = low priority bit 2 lv d i p : low-voltage detect interrupt priority bit 1 = high priority 0 = low priority bit 1 tmr3ip : tmr3 overflow interrupt priority bit 1 = high priority 0 = low priority bit 0 ccp2ip : ccp2 interrupt priority bit 1 = high priority 0 = low priority legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 75 7.0.6 int0 interrupt external interrupts on the rb0/int0, rb1/int1 and rb2/int2 pins are edge triggered: either rising if the corresponding intedgx bit is set in the intcon2 reg- ister, or falling, if the intedgx bit is clear. when a valid edge appears on the rbx/intx pin, the corresponding flag bit intxf is set. this interrupt can be disabled by clearing the corresponding enable bit intxe. flag bit intxf must be cleared in software in the interrupt ser- vice routine before re-enabling the interrupt. all exter- nal interrupts (int0, int1 and int2) can wake-up the processor from sleep, if bit intxe was set prior to going into sleep. if the global interrupt enable bit gie set, the processor will branch to the interrupt vector fol- lowing wake-up. interrupt priority for int1 and int2 is determined by the value contained in the interrupt priority bits int1ip (intcon3<6>) and int2ip (intcon3<7>). there is no priority bit associated with int0. it is always a high priority interrupt source. 7.0.7 tmr0 interrupt in 8-bit mode (which is the default), an overflow (ffh ? 00h) in the tmr0 register will set flag bit tmr0if. in 16-bit mode, an overflow (ffffh ? 0000h) in the tmr0h:tmr0l registers will set flag bit tmr0if. the interrupt can be enabled/disabled by setting/clearing enable bit t0ie (intcon<5>). interrupt priority for timer0 is determined by the value contained in the interrupt priority bit tmr0ip (intcon2<2>). see sec- tion 8.0 for further details on the timer0 module. 7.0.8 portb interrupt on change an input change on portb<7:4> sets flag bit rbif (intcon<0>). the interrupt can be enabled/disabled by setting/clearing enable bit rbie (intcon<3>). interrupt priority for portb interrupt on change is determined by the value contained in the interrupt pri- ority bit rbip (intcon2<0>). 7.1 context saving during interrupts during an interrupt, the return pc value is saved on the stack. additionally, the wreg, status and bsr reg- isters are saved on the fast return stack. if a fast return from interrupt is not used (see section 4.3), the user may need to save the wreg, status and bsr regis- ters in software. depending on the users application, other registers may also need to be saved. example 6- 1 saves and restores the wreg, status and bsr registers during an interrupt service routine. example 7-1: saving status, wreg and bsr registers in ram movwf w_temp ; w_temp is in virtual bank movff status, status_temp ; status_temp located anywhere movff bsr, bsr_temp ; bsr located anywhere ; ; user isr code ; movff bsr_temp, bsr ; restore bsr movf w_temp, w ; restore wreg movff status_temp, status ; restore status
pic18cxx2 ds39026b-page 76 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 77 8.0 i/o ports depending on the device selected, there are either five ports or three ports available. some pins of the i/o ports are multiplexed with an alternate function from the peripheral features on the device. in general, when a peripheral is enabled, that pin may not be used as a general purpose i/o pin. each port has three registers for its operation. these registers are: ? tris register (data direction register) ? port register (reads the levels on the pins of the device) ? lat register (output latch) the data latch (lat register) is useful for read-modify- write operations on the value that the i/o pins are driv- ing. 8.1 p orta, trisa a nd lata registers porta is a 6-bit wide bi-directional port. the corre- sponding data direction register is trisa. setting a trisa bit (=1) will make the corresponding porta pin an input, (i.e., put the corresponding output driver in a hi-impedance mode). clearing a trisa bit (=0) will make the corresponding porta pin an output, (i.e., put the contents of the output latch on the selected pin). reading the porta register reads the status of the pins, whereas writing to it will write to the port latch. the data latch register (lata) is also memory mapped. read-modify-write operations on the lata register reads and writes the latched output value for porta. the ra4 pin is multiplexed with the timer0 module clock input to become the ra4/t0cki pin. the ra4/ t0cki pin is a schmitt trigger input and an open drain output. all other ra port pins have ttl input levels and full cmos output drivers. the other porta pins are multiplexed with analog inputs and the analog v ref + and v ref - inputs. the operation of each pin is selected by clearing/setting the control bits in the adcon1 register (a/d control register1). the trisa register controls the direction of the ra pins, even when they are being used as analog inputs. the user must ensure the bits in the trisa register are maintained set when using them as analog inputs. example 8-1: initializing porta note: on a power-on reset, these pins are con- figured as inputs and read as '0'. note: on a power-on reset, these pins are con- figured as analog inputs and read as '0'. clrf porta ; initialize porta by ; clearing output ; data latches clrf lata ; alternate method ; to clear output ; data latches movlw 0x07 ; configure a/d movwf adcon1 ; for digital inputs movlw 0xcf ; value used to ; initialize data ; direction movwf trisa ; set ra<3:0> as inputs ; ra<5:4> as outputs
pic18cxx2 ds39026b-page 78 preliminary ? 7/99 microchip technology inc. figure 8-1: block diagram of ra3:ra0 and ra5 pins figure 8-2: block diagram of ra4/ t0cki pin figure 8-3: block diagram of ra6 data bus q d q ck q d q ck qd en p n wr lata wr trisa data latch tris latch rd trisa rd porta v ss v dd i/o pin (1) note 1: i/o pins have protection diodes to v dd and v ss . analog input mode ttl input buffer to a/d converter and lvd modules rd lata or porta ss input (ra5 only) data bus wr trisa rd porta data latch tris latch rd trisa schmitt trigger input buffer n v ss i/o pin (1) tmr0 cock input note 1: i/o pin has protection diodes to v ss only. q d q ck q d q ck en qd en rd lata wr lata or porta data bus q d q ck q d q ck qd en p n wr lata wr data latch tris latch rd trisa rd porta v ss v dd i/o pin (1) note 1: i/o pins have protection diodes to v dd and v ss . or porta rd lata ecra6 or data bus ecra6 or enable data bus ttl input buffer rcra6 rcra6 enable trisa
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 79 table 8-1: porta functions table 8-2: summary of registers associated with porta name bit# buffer function ra0/an0 bit0 ttl input/output or analog input ra1/an1 bit1 ttl input/output or analog input ra2/an2/v ref - bit2 ttl input/output or analog input or v ref - ra3/an3/v ref + bit3 ttl input/output or analog input or v ref + ra4/t0cki bit4 st input/output or external clock input for timer0 output is open drain type ra5/ss/ an4/lvdin bit5 ttl input/output or slave select input for synchronous serial port or analog input, or low voltage detect input osc2/clko/ra6 bit6 osc2 or clock output or i/o pin legend: ttl = ttl input, st = schmitt trigger input name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets porta ra6 ra5 ra4 ra3 ra2 ra1 ra0 --0x 0000 --0u 0000 lata latch a data output register --xx xxxx --uu uuuu trisa porta data direction register --11 1111 --11 1111 adcon1 adfm adcs2 pcfg3 pcfg2 pcfg1 pcfg0 --0- 0000 --0- 0000 legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. shaded cells are not used by porta.
pic18cxx2 ds39026b-page 80 preliminary ? 7/99 microchip technology inc. 8.2 portb, trisb a nd latb registers portb is an 8-bit wide bi-directional port. the corre- sponding data direction register is trisb. setting a trisb bit (=1) will make the corresponding portb pin an input, (i.e., put the corresponding output driver in a hi-impedance mode). clearing a trisb bit (=0) will make the corresponding portb pin an output, ( i.e. put the contents of the output latch on the selected pin). the data latch register (latb) is also memory mapped. read-modify-write operations on the latb register reads and writes the latched output value for portb. example 8-2: initializing portb each of the portb pins has a weak internal pull-up. a single control bit can turn on all the pull-ups. this is per- formed by clearing bit rbpu (intcon2<7>). the weak pull-up is automatically turned off when the port pin is configured as an output. the pull-ups are dis- abled on a power-on reset. four of portbs pins, rb7:rb4, have an interrupt on change feature. only pins configured as inputs can cause this interrupt to occur (i.e. any rb7:rb4 pin con- figured as an output is excluded from the interrupt on change comparison). the input pins (of rb7:rb4) are compared with the old value latched on the last read of portb. the mismatch outputs of rb7:rb4 are ored together to generate the rb port change inter- rupt with flag bit rbif (intcon<0>). this interrupt can wake the device from sleep. the user, in the interrupt service routine, can clear the inter- rupt in the following manner: a) any read or write of portb (except with the movff instruction). this will end the mismatch condition. b) clear flag bit rbif. a mismatch condition will continue to set flag bit rbif. reading portb will end the mismatch condition and allow flag bit rbif to be cleared. the interrupt on change feature is recommended for wake-up on key depression operation and operations where portb is only used for the interrupt on change feature. polling of portb is not recommended while using the interrupt on change feature. figure 8-4: block diagram of rb7:rb4 pins figure 8-5: block diagram of rb2:rb0 pins clrf portb ; initialize portb by ; clearing output ; data latches clrf latb ; alternate method ; to clear output ; data latches movlw 0xcf ; value used to ; initialize data ; direction movwf trisb ; set rb<3:0> as inputs ; rb<5:4> as outputs ; rb<7:6> as inputs data latch from other rbpu (2) p v dd i/o q d ck q d ck qd en qd en data bus wr latb wr trisb set rbif tris latch rd trisb rd portb rb7:rb4 pins weak pull-up rd portb latch ttl input buffer pin (1) st buffer rbx/intx q3 q1 rd latb or portb note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit (intcon2<7>). data latch rbpu (2) p v dd q d ck q d ck qd en data bus wr port wr tris rd tris rd port weak pull-up rd port rb0/int i/o pin (1) ttl input buffer schmitt trigger buffer tris latch note 1: i/o pins have diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate tris bit(s) and clear the rbpu bit (option_reg<7>).
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 81 figure 8-6: block diagram of rb3 data latch p v dd q d ck q d en data bus wr latb or wr trisb rd trisb rd portb weak pull-up ccp2 input (3) ttl input buffer schmitt trigger buffer tris latch rd latb wr portb rbpu (2) ck d enable (3) ccp output rd portb ccp output (3) 1 0 p n v dd v ss i/o pin (1) q ccp2mx ccp2mx = 0 note 1: i/o pin has diode protection to v dd and v ss . 2: to enable weak pull-ups, set the appropriate ddr bit(s) and clear the rbpu bit (intcon2<7>). 3: the ccp2 input/output is multiplexed with rb3 if the ccp2mx bit is enabled (=0) in the configuration register.
pic18cxx2 ds39026b-page 82 preliminary ? 7/99 microchip technology inc. table 8-3: portb functions table 8-4: summary of registers associated with portb name bit# buffer function rb0/int0 bit0 ttl/st (1) input/output pin or external interrupt input1. internal software programmable weak pull-up. rb1/int1 bit1 ttl/st (1) input/output pin or external interrupt input2. internal software programma- ble weak pull-up. rb2/int2 bit2 ttl/st (1) input/output pin or external interrupt input3. internal software programma- ble weak pull-up. rb3/ccp2 (3) bit3 ttl/st (4) input/output pin. capture2 input/compare2 output/pwm output when ccp2mx configuration bit is enabled. internal software programmable weak pull-up. rb4 bit4 ttl input/output pin (with interrupt on change). internal software programma- ble weak pull-up. rb5 bit5 ttl input/output pin (with interrupt on change). internal software programma- ble weak pull-up. rb6 bit6 ttl/st (2) input/output pin (with interrupt on change). internal software programma- ble weak pull-up. serial programming clock. rb7 bit7 ttl/st (2) input/output pin (with interrupt on change). internal software programma- ble weak pull-up. serial programming data. legend: ttl = ttl input, st = schmitt trigger input note 1: this buffer is a schmitt trigger input when configured as the external interrupt. 2: this buffer is a schmitt trigger input when used in serial programming mode. 3: a device configuration bit selects which i/o pin the ccp2 pin is multiplexed on. 4: this buffer is a schmitt trigger input when configured as the ccp2 input. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets portb rb7 rb6 rb5 rb4 rb3 rb2 rb1 rb0 xxxx xxxx uuuu uuuu latb latb data output register trisb portb data direction register 1111 1111 1111 1111 intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u intcon2 rbpu intedg0 intedg1 intedg2 tmr0ip rbip 1111 -1-1 1111 -1-1 intcon3 int2ip int1ip int2ie int1ie int2if int1if 11-0 0-00 11-0 0-00 legend: x = unknown, u = unchanged. shaded cells are not used by portb.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 83 8.3 portc, trisc a nd latc registers portc is an 8 bit wide bi-directional port. the corre- sponding data direction register is trisc. setting a trisc bit (=1) will make the corresponding portc pin an input, (i.e., put the corresponding output driver in a hi-impedance mode). clearing a trisc bit (=0) will make the corresponding portc pin an output, (i.e., put the contents of the output latch on the selected pin). the data latch register (latc) is also memory mapped. read-modify-write operations on the latc register reads and writes the latched output value for portc. portc is multiplexed with several peripheral functions (table 8-5). portc pins have schmitt trigger input buffers. when enabling peripheral functions, care should be taken in defining tris bits for each portc pin. some peripherals override the tris bit to make a pin an out- put, while other peripherals override the tris bit to make a pin an input. the user should refer to the corre- sponding peripheral section for the correct tris bit set- tings. the pin override value is not loaded into the tris reg- ister. this allows read-modify-write of the tris register, without concern due to peripheral overrides. example 8-3: initializing portc figure 8-7: portc block diagram (peripheral output override) clrf portc ; initialize portc by ; clearing output ; data latches clrf latc ; alternate method ; to clear output ; data latches movlw 0xcf ; value used to ; initialize data ; direction movwf trisc ; set rc<3:0> as inputs ; rc<5:4> as outputs ; rc<7:6> as inputs data bus wr latc or wr trisc rd trisc q d q ck qd ck peripheral data out 1 0 q d q ck rd portc peripheral data in wr portc rd latc q peripheral out select peripheral output enable rc7: rc0 st buffer
pic18cxx2 ds39026b-page 84 preliminary ? 7/99 microchip technology inc. table 8-5: portc functions table 8-6: summary of registers associated with portc name bit# buffer type function rc0/t1oso/t1cki bit0 st input/output port pin or timer1 oscillator output/timer1 clock input rc1/t1osi/ccp2 bit1 st input/output port pin, timer1 oscillator input, or capture2 input/ compare2 output/pwm output when ccp2mx configuration bit is disabled. rc2/ccp1 bit2 st input/output port pin or capture1 input/compare1 output/pwm1 output rc3/sck/scl bit3 st rc3 can also be the synchronous serial clock for both spi and i 2 c modes. rc4/sdi/sda bit4 st rc4 can also be the spi data in (spi mode) or data i/o (i 2 c mode). rc5/sdo bit5 st input/output port pin or synchronous serial port data output rc6/tx/ck bit6 st input/output port pin, addressable usart asynchronous transmit, or addressable usart synchronous clock rc7/rx/dt bit7 st input/output port pin, addressable usart asynchronous receive, or addressable usart synchronous data legend: st = schmitt trigger input name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets portc rc7 rc6 rc5 rc4 rc3 rc2 rc1 rc0 xxxx xxxx uuuu uuuu latc latc data output register xxxx xxxx uuuu uuuu trisc portc data direction register 1111 1111 1111 1111 legend: x = unknown, u = unchanged.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 85 8.4 portd, trisd a nd l atd registers this section is applicable to only the pic18c4x2 devices. portd is an 8 bit wide bi-directional port. the corre- sponding data direction register is trisd. setting a trisd bit (=1) will make the corresponding portd pin an input, (i.e., put the corresponding output driver in a hi-impedance mode). clearing a trisd bit (=0) will make the corresponding portd pin an output, (i.e., put the contents of the output latch on the selected pin). the data latch register (latd) is also memory mapped. read-modify-write operations on the latd register reads and writes the latched output value for portd. portd is an 8-bit port with schmitt trigger input buff- ers. each pin is individually configurable as an input or output. portd can be configured as an 8-bit wide micropro- cessor port (parallel slave port) by setting control bit pspmode (trise<4>). in this mode, the input buffers are ttl. see section 8.6 for additional information on the parallel slave port (psp). example 8-4: initializing portd figure 8-8: portd block diagram in i/o port mode clrf portd ; initialize portd by ; clearing output ; data latches clrf latd ; alternate method ; to clear output ; data latches movlw 0xcf ; value used to ; initialize data ; direction movwf trisd ; set rd<3:0> as inputs ; rd<5:4> as outputs ; rd<7:6> as inputs data bus wr latd wr trisd rd portd data latch tris latch rd trisd schmitt tr i g g e r input buffer i/o pin (1) note 1: i/o pins have protection diodes to v dd and v ss . q d ck q d ck en qd en rd latd or portd
pic18cxx2 ds39026b-page 86 preliminary ? 7/99 microchip technology inc. table 8-7: portd functions table 8-8: summary of registers associated with portd name bit# buffer type function rd0/psp0 bit0 st/ttl (1) input/output port pin or parallel slave port bit0 rd1/psp1 bit1 st/ttl (1) input/output port pin or parallel slave port bit1 rd2/psp2 bit2 st/ttl (1) input/output port pin or parallel slave port bit2 rd3/psp3 bit3 st/ttl (1) input/output port pin or parallel slave port bit3 rd4/psp4 bit4 st/ttl (1) input/output port pin or parallel slave port bit4 rd5/psp5 bit5 st/ttl (1) input/output port pin or parallel slave port bit5 rd6/psp6 bit6 st/ttl (1) input/output port pin or parallel slave port bit6 rd7/psp7 bit7 st/ttl (1) input/output port pin or parallel slave port bit7 legend: st = schmitt trigger input, ttl = ttl input note 1: input buffers are schmitt triggers when in i/o mode and ttl buffer when in parallel slave port mode. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets portd rd7 rd6 rd5 rd4 rd3 rd2 rd1 rd0 xxxx xxxx uuuu uuuu latd latd data output register xxxx xxxx uuuu uuuu trisd portd data direction register 1111 1111 1111 1111 trise ibf obf ibov pspmode porte data direction bits 0000 -111 0000 -111 legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by portd.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 87 8.5 porte, trise a nd l ate register s this section is only applicable to the pic18c4x2 devices. porte is an 3 bit wide bi-directional port. the corre- sponding data direction register is trise. setting a trise bit (=1) will make the corresponding porte pin an input, (i.e., put the corresponding output driver in a hi-impedance mode). clearing a trise bit (=0) will make the corresponding porte pin an output, (i.e., put the contents of the output latch on the selected pin). the data latch register (late) is also memory mapped. read-modify-write operations on the late register reads and writes the latched output value for porte. porte has three pins re0/rd /an5, re1/wr /an6 and re2/cs /an7, which are individually configurable as inputs or outputs. these pins have schmitt trigger input buffers. figure 8-1 shows the trise register, which also con- trols the parallel slave port operation. capture2 input/ compare2 output/pwm output when ccp2mx config- uration bit is enabled. porte pins are multiplexed with analog inputs. when selected as an analog input, these pins will read as '0's. trise controls the direction of the re pins, even when they are being used as analog inputs. the user must make sure to keep the pins configured as inputs when using them as analog inputs. example 8-5: initializing porte figure 8-9: porte block diagram in i/o port mode note: on a power-on reset, these pins are con- figured as analog inputs. clrf porte ; initialize porte by ; clearing output ; data latches clrf late ; alternate method ; to clear output ; data latches movlw 0x07 ; configure a/d movwf adcon1 ; for digital inputs movlw 0x03 ; value used to ; initialize data ; direction movwf trisc ; set re<0> as inputs ; re<1> as outputs ; re<2> as inputs data bus wr late wr trise rd porte data latch tris latch rd trise schmitt tr i g g e r input buffer q d ck q d ck en qd en i/o pin (1) note 1: i/o pins have protection diodes to v dd and v ss . rd late or porte to analog converter
pic18cxx2 ds39026b-page 88 preliminary ? 7/99 microchip technology inc. register 8-1: trise register r-0 r-0 r/w-0 r/w-0 u-0 r/w-1 r/w-1 r/w-1 ibf obf ibov pspmode trise2trise1trise0 bit 7 bit 0 bit 7 ibf: input buffer full status bit 1 = a word has been received and waiting to be read by the cpu 0 = no word has been received bit 6 obf : output buffer full status bit 1 = the output buffer still holds a previously written word 0 = the output buffer has been read bit 5 ibov : input buffer overflow detect bit (in microprocessor mode) 1 = a write occurred when a previously input word has not been read (must be cleared in software) 0 = no overflow occurred bit 4 pspmode : parallel slave port mode select bit 1 = parallel slave port mode 0 = general purpose i/o mode bit 3 unimplemented: read as '0' bit 2 trise2 : re2 direction control bit 1 = input 0 = output bit 1 trise1 : re1 direction control bit 1 = input 0 = output bit 0 trise0 : re0 direction control bit 1 = input 0 = output legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 89 table 8-9: porte functions table 8-10: summary of registers associated with porte name bit# buffer type function re0/rd /an5 bit0 st/ttl (1) input/output port pin or read control input in parallel slave port mode or analog input: r d 1 = not a read operation 0 = read operation. reads portd register (if chip selected) re1/wr /an6 bit1 st/ttl (1) input/output port pin or write control input in parallel slave port mode or analog input: w r 1 = not a write operation 0 = write operation. writes portd register (if chip selected) re2/cs /an7 bit2 st/ttl (1) input/output port pin or chip select control input in parallel slave port mode or analog input: c s 1 = device is not selected 0 = device is selected legend: st = schmitt trigger input, ttl = ttl input note 1: input buffers are schmitt triggers when in i/o mode and ttl buffers when in parallel slave port mode. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets porte re2re1re0 ---- -000 ---- -000 late late data output register ---- -xxx ---- -uuu trise ibf obf ibov pspmode porte data direction bits 0000 -111 0000 -111 adcon1 adfm adcs2 pcfg3 pcfg2 pcfg1 pcfg0 --0- -000 --0- -000 legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by porte.
pic18cxx2 ds39026b-page 90 preliminary ? 7/99 microchip technology inc. 8.6 parallel slave port the parallel slave port is implemented on the 40-pin devices only (pic18c4x2). portd operates as an 8-bit wide parallel slave port, or microprocessor port when control bit pspmode (trise<4>) is set. in slave mode it is asynchronously readable and writable by the external world through rd control input pin re0/rd and wr control input pin re1/wr . it can directly interface to an 8-bit microprocessor data bus. the external microprocessor can read or write the portd latch as an 8-bit latch. setting bit pspmode enables port pin re0/rd to be the rd input, re1/wr to be the wr input and re2/cs to be the cs (chip select) input. for this functionality, the corresponding data direction bits of the trise register (trise<2:0>) must be configured as inputs (set). the a/d port con- figuration bits pcfg2:pcfg0 (adcon1<2:0>) must be set, which will configure pins re2:re0 as digital i/o. a write to the psp occurs when both the cs and wr lines are first detected low. a read from the psp occurs when both the cs and rd lines are first detected low. the porte i/o pins become control inputs for the microprocessor port when bit pspmode (trise<4>) is set. in this mode, the user must make sure that the trise<2:0> bits are set (pins are configured as digital inputs), and the adcon1 is configured for digital i/o. in this mode, the input buffers are ttl. figure 8-10: portd and porte block diagram (parallel slave port) figure 8-11: parallel slave port write waveforms data bus wr latd rdx q d ck en qd en rd portd pin one bit of portd set interrupt flag pspif (pir1<7>) read chip select write rd cs wr note: i/o pin has protection diodes to v dd and v ss . ttl ttl ttl ttl or portd rd latd data latch q1 q2 q3 q4 cs q1 q2 q3 q4 q1 q2 q3 q4 wr rd ibf obf pspif portd<7:0>
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 91 figure 8-12: parallel slave port read waveforms table 8-11: registers associated with parallel slave port name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets portd port data latch when written; port pins when read xxxx xxxx uuuu uuuu latd latd data output bits xxxx xxxx uuuu uuuu trisd portd data direction bits 1111 1111 1111 1111 porte re2re1re0 ---- -000 ---- -000 late late data output bits ---- -xxx ---- -uuu trise ibf obf ibov pspmode porte data direction bits 0000 -111 0000 -111 intcon gie/ gieh peie/ giel tmr0if int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 adcon1 adfm adcs2 pcfg3 pcfg2 pcfg1 pcfg0 --0- -000 --0- -000 legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by the parallel slave port. q1 q2 q3 q4 cs q1 q2 q3 q4 q1 q2 q3 q4 wr ibf pspif rd obf portd<7:0>
pic18cxx2 ds39026b-page 92 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 93 9.0 timer0 module the timer0 module has the following features: ? software selectable as an 8-bit or 16-bit timer/ counter ? readable and writable ? dedicated 8-bit software programmable prescaler ? clock source selectable to be external or internal ? interrupt on overflow from ffh to 00h in 8-bit mode and ffffh to 0000h in 16-bit mode ? edge select for external clock figure 9-1 shows a simplified block diagram of the timer0 module in 8-bit mode and figure 9-1 shows a simplified block diagram of the timer0 module in 16-bit mode. the t0con register is a readable and writable register that controls all the aspects of timer0, including the prescale selection. register 9-1: t0con: timer0 control register r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 r/w-1 tmr0on t08bit t0cs t0se psa t0ps2 t0ps1 t0ps0 bit 7 bit 0 bit 7 tmr0on: timer0 on/off control bit 1 = enables timer0 0 = stops timer0 bit 6 t08bit : timer0 8-bit/16-bit control bit 1 = timer0 is configured as an 8-bit timer/counter 0 = timer0 is configured as a 16-bit timer/counter bit 5 t0cs : timer0 clock source select bit 1 = transition on t0cki pin 0 = internal instruction cycle clock (clkout) bit 4 t0se : timer0 source edge select bit 1 = increment on high-to-low transition on t0cki pin 0 = increment on low-to-high transition on t0cki pin bit 3 psa : timer0 prescaler assignment bit 1 = timer0 prescaler is not assigned. timer0 clock input bypasses prescaler 0 = timer0 prescaler is assigned. timer0 clock input comes from prescaler output bit 2:0 t0ps2:t0ps0 : timer0 prescaler select bits 111 = 1:256 prescale value 110 = 1:128 prescale value 101 = 1:64 prescale value 100 = 1:32 prescale value 011 = 1:16 prescale value 010 = 1:8 prescale value 001 = 1:4 prescale value 000 = 1:2 prescale value legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 94 preliminary ? 7/99 microchip technology inc. figure 9-1: timer0 block diagram in 8-bit mode figure 9-2: timer0 block diagram in 16-bit mode note: upon reset, timer0 is enabled in 8-bit mode with clock input from t0cki max. prescale. ra4/t0cki t0se 0 1 0 1 pin t0cs f osc /4 programmable prescaler sync with internal clocks tmr0 (2 tcy delay) data bus 8 psa t0ps2, t0ps1, t0ps0 set interrupt flag bit tmr0if on overflow 3 note: upon reset, timer0 is enabled in 8-bit mode with clock input from t0cki max. prescale. t0cki pin t0se 0 1 0 1 t0cs f osc /4 programmable prescaler sync with internal clocks tmr0l (2 tcy delay) data bus<7:0> 8 psa t0ps2, t0ps1, t0ps0 set interrupt flag bit tmr0if on overflow 3 tmr0 tmr0h high byte 8 8 8 read tmr0l write tmr0l
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 95 9.1 timer0 operation timer0 can operate as a timer or as a counter. timer mode is selected by clearing the t0cs bit. in timer mode, the timer0 module will increment every instruction cycle (without prescaler). if the tmr0 regis- ter is written, the increment is inhibited for the following two instruction cycles. the user can work around this by writing an adjusted value to the tmr0 register. counter mode is selected by setting the t0cs bit. in counter mode, timer0 will increment either on every rising or falling edge of pin ra4/t0cki. the increment- ing edge is determined by the timer0 source edge select bit (t0se). clearing the t0se bit selects the ris- ing edge. restrictions on the external clock input are discussed below. when an external clock input is used for timer0, it must meet certain requirements. the requirements ensure the external clock can be synchronized with the internal phase clock (t osc ). also, there is a delay in the actual incrementing of timer0 after synchronization. 9.2 p re scaler an 8-bit counter is available as a prescaler for the timer0 module. the prescaler is not readable or writ- able. the psa and t0ps2:t0ps0 bits determine the pres- caler assignment and prescale ratio. clearing bit psa will assign the prescaler to the timer0 module. when the prescaler is assigned to the timer0 module, prescale values of 1:2, 1:4, ..., 1:256 are selectable. when assigned to the timer0 module, all instructions writing to the tmr0 register (e.g. clrf tmr0, movwf tmr0, bsf tmr0, x ....etc.) will clear the prescaler count. 9.2.1 switching prescaler assignment the prescaler assignment is fully under software con- trol, ( i.e., it can be changed on-the-fly during program execution). 9.3 timer0 interrupt the tmr0 interrupt is generated when the tmr0 reg- ister overflows from ffh to 00h in 8-bit mode or ffffh to 0000h in 16-bit mode. this overflow sets the tmr0if bit. the interrupt can be masked by clearing the tmr0ie bit. the tmr0ie bit must be cleared in soft- ware by the timer0 module interrupt service routine before re-enabling this interrupt. the tmr0 interrupt cannot awaken the processor from sleep, since the timer is shut off during sleep. 9.4 16-bit mode timer reads and writes tmr0h is not the high byte of the timer/counter in 16- bit mode, but is actually a buffered version of the high byte of timer0 (refer to figure 9-1). the high byte of the timer0 counter/timer is not directly readable nor writable. tmr0h is updated with the contents of the high byte of timer0 during a read of tmr0l. this pro- vides the ability to read all 16-bits of timer0 without having to verify that the read of the high and low byte were valid due to a rollover between successive reads of the high and low byte. a write to the high byte of timer0 must also take place through the tmr0h buffer register. timer0 high byte is updated with the contents of tmr0h when a write occurs to tmr0l. this allows all 16 bits of timer0 to be updated at once. table 9-1: registers associated with timer0 note: writing to tmr0 when the prescaler is assigned to timer0 will clear the prescaler count, but will not change the prescaler assignment. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets tmr0l timer0 modules low byte register xxxx xxxx uuuu uuuu tmr0h timer0 modules high byte register 0000 0000 0000 0000 intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u t0con tmr0on t08bit t0cs t0se psa t0ps2 t0ps1 t0ps0 1111 1111 1111 1111 trisa porta data direction register --11 1111 --11 1111 legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. shaded cells are not used by timer0.
pic18cxx2 ds39026b-page 96 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 97 10.0 timer1 module the timer1 module timer/counter has the following fea- tures: ? 16-bit timer/counter (two 8-bit registers; tmr1h and tmr1l) ? readable and writable (both registers) ? internal or external clock select ? interrupt on overflow from ffffh to 0000h ? reset from ccp module special event trigger figure 10-1 is a simplified block diagram of the timer1 module. register 10-1 shows the timer1 control register. this register controls the operating mode of the timer1 module as well as contains the timer1 oscillator enable bit (t1oscen). timer1 can be enabled/disabled by setting/clearing control bit tmr1on (t1con<0>). register 10-1: t1con: timer1 control register r/w-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 rd16 t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on bit 7 bit 0 bit 7 rd16: 16-bit read/write mode enable bit 1 = enables register read/write of timer1 in one 16-bit operation 0 = enables register read/write of timer1 in two 8-bit operations bit 6 unimplemented: read as '0' bit 5:4 t1ckps1:t1ckps0 : timer1 input clock prescale select bits 11 = 1:8 prescale value 10 = 1:4 prescale value 01 = 1:2 prescale value 00 = 1:1 prescale value bit 3 t1oscen: timer1 oscillator enable bit 1 = timer1 oscillator is enabled 0 = timer1 oscillator is shut off. the oscillator inverter and feedback resistor are turned off to eliminate power drain bit 2 t1sync : timer1 external clock input synchronization select bit when tmr1cs = 1: 1 = do not synchronize external clock input 0 = synchronize external clock input when tmr1cs = 0: this bit is ignored. timer1 uses the internal clock when tmr1cs = 0. bit 1 tmr1cs: timer1 clock source select bit 1 = external clock from pin rc0/t1oso/t13cki (on the rising edge) 0 = internal clock (f osc /4) bit 0 tmr1on: timer1 on bit 1 = enables timer1 0 = stops timer1 legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 98 preliminary ? 7/99 microchip technology inc. 10.1 timer1 operation timer1 can operate in one of these modes: ?as a timer ? as a synchronous counter ? as an asynchronous counter the operating mode is determined by the clock select bit, tmr1cs (t1con<1>). when tmr1cs = 0, timer1 increments every instruc- tion cycle. when tmr1cs = 1, timer1 increments on every rising edge of the external clock input or the timer1 oscillator, if enabled. when the timer1 oscillator is enabled (t1oscen is set), the rc1/t1osi and rc0/t1oso/t1cki pins become inputs. that is, the trisc<1:0> value is ignored. timer1 also has an internal reset input. this reset can be generated by the ccp module (section 13.0). figure 10-1: timer1 block diagram figure 10-2: timer1 block diagram: 16-bit read/write mode tmr1h tmr1l t1sync tmr1cs t1ckps1:t1ckps0 sleep input f osc /4 internal clock tmr1on on/off prescaler 1, 2, 4, 8 synchronize det 1 0 0 1 synchronized clock input 2 tmr1if overflow tmr1 clr ccp special event trigger t1oscen enable oscillator ( 1 ) t1osc interrupt flag bit note 1: when enable bit t1oscen is cleared, the inverter and feedback resistor are turned off. this eliminates power drain. t1osi t1cki/t1oso timer 1 tmr1l t1osc t1sync tmr1cs t1ckps1:t1ckps0 sleep input t1oscen enable oscillator (1) tmr1if overflow interrupt fosc/4 internal clock tmr1on on/off prescaler 1, 2, 4, 8 synchronize det 1 0 0 1 synchronized clock input 2 t13cki/t1oso t1osi tmr1 flag bit note 1: when enable bit t1oscen is cleared, the inverter and feedback resistor are turned off. this eliminates power drain. high byte data bus<7:0> 8 tmr1h 8 8 8 read tmr1l write tmr1l
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 99 10.2 timer1 o scillator a crystal oscillator circuit is built-in between pins t1osi (input) and t1oso (amplifier output). it is enabled by setting control bit t1oscen (t1con<3>). the oscilla- tor is a low power oscillator rated up to 200 khz. it will continue to run during sleep. it is primarily intended for a 32 khz crystal. table 10-1 shows the capacitor selection for the timer1 oscillator. the user must provide a software time delay to ensure proper start-up of the timer1 oscillator. 10.3 t imer1 interrupt the tmr1 register pair (tmr1h:tmr1l) increments from 0000h to ffffh and rolls over to 0000h. the tmr1 interrupt, if enabled, is generated on overflow, which is latched in interrupt flag bit tmr1if (pir1<0>). this interrupt can be enabled/disabled by setting/clear- ing tmr1 interrupt enable bit tmr1ie (pie1<0>). 10.4 resetting timer1 using a ccp trigger output if the ccp module is configured in compare mode to generate a special event trigger" (ccp1m3:ccp1m0 = 1011), this signal will reset timer1 and start an a/d conversion (if the a/d module is enabled). timer1 must be configured for either timer or synchro- nized counter mode to take advantage of this feature. if timer1 is running in asynchronous counter mode, this reset operation may not work. in the event that a write to timer1 coincides with a spe- cial event trigger from ccp1, the write will take prece- dence. in this mode of operation, the ccpr1h:ccpr1l regis- ters pair effectively becomes the period register for timer1. 10.5 timer1 16-bit read/write mode timer1 can be configured for 16-bit reads and writes (see figure 10-2). when the rd16 control bit (t1con<7>) is set, the address for tmr1h is mapped to a buffer register for the high byte of timer1. a read from tmr1l will load the contents of the high byte of timer1 into the timer1 high byte buffer. this provides the user with the ability to accurately read all 16-bits of timer1 without having to determine whether a read of the high byte followed by a read of the low byte is valid due to a rollover between reads. a write to the high byte of timer1 must also take place through the tmr1h buffer register. timer1 high byte is updated with the contents of tmr1h when a write occurs to tmr1l. this allows a user to write all 16 bits to both the high and low bytes of timer1 at once. the high byte of timer1 is not directly readable or writ- able in this mode. all reads and writes must take place through the timer1 high byte buffer register. writes to tmr1h do not clear the timer1 prescaler. the pres- caler is only cleared on writes to tmr1l. table 10-1: capacitor selection for the alternate oscillator osc type freq c1 c2 lp 32 khz tbd ( 1 ) tbd ( 1 ) crystal to be tested: 32.768 khz epson c-001r32.768k-a 20 ppm note 1: microchip suggests 33 pf as a starting point in validating the oscillator circuit. 2: higher capacitance increases the stability of the oscillator, but also increases the start-up time. 3: since each resonator/crystal has its own characteristics, the user should consult the resonator/crystal manufacturer for appro- priate values of external components. 4: capacitor values are for design guidance only. note: the special event triggers from the ccp1 module will not set interrupt flag bit tmr1if (pir1<0>).
pic18cxx2 ds39026b-page 100 preliminary ? 7/99 microchip technology inc. table 10-2: registers associated with timer1 as a timer/counter name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif ( 1 ) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie ( 1 ) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip ( 1 ) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu tmr1h holding register for the most significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu t1con t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on --00 0000 --uu uuuu legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by the timer1 module. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 101 notes:
pic18cxx2 ds39026b-page 102 preliminary ? 7/99 microchip technology inc. 11.0 timer2 module the timer2 module timer has the following features: ? 8-bit timer (tmr2 register) ? 8-bit period register (pr2) ? readable and writable (both registers) ? software programmable prescaler (1:1, 1:4, 1:16) ? software programmable postscaler (1:1 to 1:16) ? interrupt on tmr2 match of pr2 ? ssp module optional use of tmr2 output to gen- erate clock shift timer2 has a control register shown in register 11-1. timer2 can be shut off by clearing control bit tmr2on (t2con<2>) to minimize power consumption. figure 11-1 is a simplified block diagram of the timer2 module. figure 11-1 shows the timer2 control register. the prescaler and postscaler selection of timer2 are controlled by this register. 11.1 t imer2 operation timer2 can be used as the pwm time-base for the pwm mode of the ccp module. the tmr2 register is readable and writable, and is cleared on any device reset. the input clock (f osc /4) has a prescale option of 1:1, 1:4 or 1:16, selected by control bits t2ckps1:t2ckps0 (t2con<1:0>). the match out- put of tmr2 goes through a 4-bit postscaler (which gives a 1:1 to 1:16 scaling inclusive) to generate a tmr2 interrupt (latched in flag bit tmr2if, (pir1<1>)). the prescaler and postscaler counters are cleared when any of the following occurs: ? a write to the tmr2 register ? a write to the t2con register ? any device reset (power-on reset, mclr reset, watchdog timer reset, or brown-out reset) tmr2 is not cleared when t2con is written. register 11-1: t2con: timer2 control register u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 bit 7 bit 0 bit 7 unimplemented: read as '0' bit 6:3 toutps3:toutps0 : timer2 output postscale select bits 0000 = 1:1 postscale 0001 = 1:2 postscale ? ? ? 1111 = 1:16 postscale bit 2 tmr2on : timer2 on bit 1 = timer2 is on 0 = timer2 is off bit 1:0 t2ckps1:t2ckps0 : timer2 clock prescale select bits 00 = prescaler is 1 01 = prescaler is 4 1x = prescaler is 16 legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 103 11.2 timer2 interrupt the timer2 module has an 8-bit period register pr2. timer2 increments from 00h until it matches pr2 and then resets to 00h on the next increment cycle. pr2 is a readable and writable register. the pr2 register is ini- tialized to ffh upon reset. 11.3 output of tmr2 the output of tmr2 (before the postscaler) is fed to the synchronous serial port module, which optionally uses it to generate the shift clock. figure 11-1: timer2 block diagram table 11-1: registers associated with timer2 as a timer/counter comparator tmr2 sets flag tmr2 output (1) reset postscaler prescaler pr2 2 f osc /4 1:1 1:16 1:1, 1:4, 1:16 eq 4 bit tmr2if note 1: tmr2 register output can be software selected by the ssp module as a baud clock. to toutps3:toutps0 t2ckps1:t2ckps0 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/gieh peie/giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif ( 1 ) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie ( 1 ) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip ( 1 ) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 tmr2 timer2 modules register 0000 0000 0000 0000 t2con toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 pr2 timer2 period register 1111 1111 1111 1111 legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by the timer2 module. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ds39026b-page 104 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 105 12.0 timer3 module the timer3 module timer/counter has the following fea- tures: ? 16-bit timer/counter (two 8-bit registers; tmr3h and tmr3l) ? readable and writable (both registers) ? internal or external clock select ? interrupt on overflow from ffffh to 0000h ? reset from ccp module trigger figure 12-1 is a simplified block diagram of the timer3 module. register 12-1 shows the timer3 control register. this register controls the operating mode of the timer3 module and sets the ccp clock source. register 10-1 shows the timer1 control register. this register controls the operating mode of the timer1 module, as well as contains the timer1 oscillator enable bit (t1oscen), which can be a clock source for timer3. register 12-1: t3con: timer3 control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 rd16 t3ccp2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on bit 7 bit 0 bit 7 rd16: 16-bit read/write mode enable 1 = enables register read/write of timer3 in one 16-bit operation 0 = enables register read/write of timer3 in two 8-bit operations bit 6,3 t3ccp2:t3ccp1: timer3 and timer1 to ccpx enable bits 1x = timer3 is the clock source for compare/capture ccp modules 01 = timer3 is the clock source for compare/capture of ccp2, timer1 is the clock source for compare/capture of ccp1 00 = timer1 is the clock source for compare/capture ccp modules bit 5:4 t3ckps1:t3ckps0 : timer3 input clock prescale select bits 11 = 1:8 prescale value 10 = 1:4 prescale value 01 = 1:2 prescale value 00 = 1:1 prescale value bit 2 t3sync : timer3 external clock input synchronization control bit (not usable if the system clock comes from timer1/timer3) when tmr3cs = 1: 1 = do not synchronize external clock input 0 = synchronize external clock input when tmr3cs = 0: this bit is ignored. timer3 uses the internal clock when tmr3cs = 0. bit 1 tmr3cs: timer3 clock source select bit 1 = external clock input from timer1 oscillator or t1cki (on the rising edge after the first falling edge) 0 = internal clock (fosc/4) bit 0 tmr3on: timer3 on bit 1 = enables timer3 0 = stops timer3 legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 106 preliminary ? 7/99 microchip technology inc. 12.1 timer3 operation timer3 can operate in one of these modes: ?as a timer ? as a synchronous counter ? as an asynchronous counter the operating mode is determined by the clock select bit, tmr3cs (t3con<1>). when tmr3cs = 0, timer3 increments every instruc- tion cycle. when tmr3cs = 1, timer3 increments on every rising edge of the timer1 external clock input or the timer1 oscillator, if enabled. when the timer1 oscillator is enabled (t1oscen is set), the rc1/t1osi and rc0/t1oso/t1cki pins become inputs. that is, the trisc<1:0> value is ignored. timer3 also has an internal reset input. this reset can be generated by the ccp module (section 12.0). figure 12-1: timer3 block diagram figure 12-2: timer3 block diagram configured in 16-bit mode tmr3h tmr3l t1osc t3sync tmr3cs t3ckps1:t3ckps0 sleep input t1oscen enable oscillator (1) tmr3if overflow interrupt fosc/4 internal clock tmr3on on/off prescaler 1, 2, 4, 8 synchronize det 1 0 0 1 synchronized clock input 2 t1oso/ t1osi flag bit (3) note 1: when enable bit t1oscen is cleared, the inverter and feedback resistor are turned off. this eliminates power drain. t13cki timer3 tmr3l t1osc t3sync tmr3cs t3ckps1:t3ckps0 sleep input t1oscen enable oscillator (1) f osc /4 internal clock tmr3on on/off prescaler 1, 2, 4, 8 synchronize det 1 0 0 1 synchronized clock input 2 t1oso/ t1osi tmr3 t13cki clr ccp special trigger t3ccpx to timer1 clock input note 1: when the t1oscen bit is cleared, the inverter and feedback resistor are turned off. this eliminates power drain. high byte data bus<7:0> 8 tmr3h 8 8 8 read tmr3l write tmr3l set tmr3if flag bit on overflow
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 107 12.2 timer1 o scillato r the timer1 oscillator may be used as the clock source for timer3. the timer1 oscillator is enabled by setting the t1oscen (t1con<3>) bit. the oscillator is a low power oscillator rated up to 200 khz. see section 10.0 for further details. 12.3 t imer3 interrupt the tmr3 register pair (tmr3h:tmr3l) increments from 0000h to ffffh and rolls over to 0000h. the tmr3 interrupt, if enabled, is generated on overflow which is latched in interrupt flag bit tmr3if (pir2<1>). this interrupt can be enabled/disabled by setting/clear- ing tmr3 interrupt enable bit tmr3ie (pie2<1>). 12.4 resetting timer3 using a ccp trigger output if the ccp module is configured in compare mode to generate a special event trigger" (ccp1m3:ccp1m0 = 1011), this signal will reset timer3. timer3 must be configured for either timer or synchro- nized counter mode to take advantage of this feature. if timer3 is running in asynchronous counter mode, this reset operation may not work. in the event that a write to timer3 coincides with a special event trigger from ccp1, the write will take precedence. in this mode of operation, the ccpr1h:ccpr1l registers pair effec- tively becomes the period register for timer3. table 12-1: registers associated with timer3 as a timer/counter note: the special event triggers from the ccp module will not set interrupt flag bit tmr3if (pir1<0>). name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir2 bclif lv d i f tmr3if ccp2if 0000 0000 0000 0000 pie2 bclie lv d i e tmr3ie ccp2ie 0000 0000 0000 0000 ipr2 bclip lv d i p tmr3ip ccp2ip 0000 0000 0000 0000 tmr3l holding register for the least significant byte of the 16-bit tmr3 register xxxx xxxx uuuu uuuu tmr3h holding register for the most significant byte of the 16-bit tmr3 register xxxx xxxx uuuu uuuu t1con t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on --00 0000 --uu uuuu t3con t3ckps2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on -000 0000 -uuu uuuu legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by the timer1 module.
pic18cxx2 ds39026b-page 108 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 109 13.0 capture/compare/pwm (ccp) modules each ccp (capture/compare/pwm) module contains a 16-bit register which can operate as a 16-bit capture register, as a 16-bit compare register or as a pwm master/slave duty cycle register. table 13-1 shows the timer resources of the ccp module modes. the operation of ccp1 is identical to that of ccp2, with the exception of the special event trigger. therefore, operation of a ccp module in the following sections is described with respect to ccp1. table 13-2 shows the interaction of the ccp modules. register 13-1: ccp1con register/ccp2con register u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 dcxb1 dcxb0 ccpxm3 ccpxm2 ccpxm1 ccpxm0 bit 7 bit 0 bit 7:6 unimplemented: read as '0' bit 5:4 dcxb1:dcxb0 : pwm duty cycle bit1 and bit0 capture mode: unused compare mode: unused pwm mode: these bits are the two lsbs (bit1 and bit0) of the 10-bit pwm duty cycle. the upper eight bits (dcx9:dcx2) of the duty cycle are found in ccprxl. bit 3:0 ccpxm3:ccpxm0 : ccpx mode select bits 0000 = capture/compare/pwm off (resets ccpx module) 0001 = reserved 0010 = compare mode, toggle output on match (ccpxif bit is set) 0011 = reserved 0100 = capture mode, every falling edge 0101 = capture mode, every rising edge 0110 = capture mode, every 4th rising edge 0111 = capture mode, every 16th rising edge 1000 = compare mode, initialize ccp pin low, on compare match force ccp pin high (ccpif bit is set) 1001 = compare mode, initialize ccp pin high, on compare match force ccp pin low (ccpif bit is set) 1010 = compare mode, generate software interrupt on compare match (ccpif bit is set, ccp pin is unaffected) 1011 = compare mode, trigger special event (ccpif bit is set) 11xx =pwm mode legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 110 preliminary ? 7/99 microchip technology inc. 13.1 ccp1 module capture/compare/pwm register1 (ccpr1) is com- prised of two 8-bit registers: ccpr1l (low byte) and ccpr1h (high byte). the ccp1con register controls the operation of ccp1. all are readable and writable. 13.2 ccp2 module capture/compare/pwm register2 (ccpr2) is com- prised of two 8-bit registers: ccpr2l (low byte) and ccpr2h (high byte). the ccp2con register controls the operation of ccp2. all are readable and writable. table 13-1: ccp mode - timer resource table 13-2: interaction of two ccp modules ccp mode timer resource capture compare pwm timer1 or timer3 timer1 or timer3 timer2 ccpx mode ccpy mode interaction capture capture tmr1 or tmr3 time-base. time base can be different for each ccp. capture compare the compare could be configured for the special event trigger, which clears either tmr1 or tmr3 depending upon which time base is used. compare compare the compare(s) could be configured for the special event trigger, which clears tmr1 or tmr3 depending upon which time base is used. pwm pwm the pwms will have the same frequency and update rate (tmr2 interrupt). pwm capture none pwm compare none
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 111 13.3 capture mode in capture mode, ccpr1h:ccpr1l captures the 16- bit value of the tmr1 or tmr3 registers when an event occurs on pin rc2/ccp1. an event is defined as: ? every falling edge ? every rising edge ? every 4th rising edge ? every 16th rising edge an event is selected by control bits ccp1m3:ccp1m0 (ccp1con<3:0>). when a capture is made, the inter- rupt request flag bit ccp1if (pir1<2>) is set. it must be cleared in software. if another capture occurs before the value in register ccpr1 is read, the old captured value will be lost. 13.3.1 ccp pin configuration in capture mode, the rc2/ccp1 pin should be config- ured as an input by setting the trisc<2> bit. 13.3.2 timer1/timer3 mode selection the timers that are to be used with the capture feature (either timer1 and/or timer3) must be running in timer mode or synchronized counter mode. in asynchronous counter mode, the capture operation may not work. the timer to be used with each ccp module is selected in the t3con register. 13.3.3 software interrupt when the capture mode is changed, a false capture interrupt may be generated. the user should keep bit ccp1ie (pie1<2>) clear to avoid false interrupts and should clear the flag bit ccp1if following any such change in operating mode. 13.3.4 ccp prescaler there are four prescaler settings, specified by bits ccp1m3:ccp1m0. whenever the ccp module is turned off or the ccp module is not in capture mode, the prescaler counter is cleared. this means that any reset will clear the prescaler counter. switching from one capture prescaler to another may generate an interrupt. also, the prescaler counter will not be cleared, therefore the first capture may be from a non-zero prescaler. example 13-1 shows the recom- mended method for switching between capture pres- calers. this example also clears the prescaler counter and will not generate the false interrupt. example 13-1: changing between capture prescalers figure 13-1: capture mode operation block diagram note: if the rc2/ccp1 is configured as an out- put, a write to the port can cause a capture condition. clrf ccp1con, f ; turn ccp module off movlw new_capt_ps ; load wreg with the ; new prescaler mode ; value and ccp on movwf ccp1con ; load ccp1con with ; this value ccpr1h ccpr1l tmr1h tmr1l set flag bit ccp1if tmr3 enable qs ccp1con<3:0> ccp1 pin prescaler ? 1, 4, 16 and edge detect tmr3h tmr3l tmr1 enable t3ccp2 t3ccp2 ccpr2h ccpr2l tmr1h tmr1l set flag bit ccp2if tmr3 enable qs ccp2con<3:0> ccp2 pin prescaler ? 1, 4, 1 6 and edge detect tmr3h tmr3l tmr1 enable t3ccp2 t3ccp1 t3ccp2 t3ccp1
pic18cxx2 ds39026b-page 112 preliminary ? 7/99 microchip technology inc. 13.4 c ompare mode in compare mode, the 16-bit ccpr1 (ccpr2) register value is constantly compared against either the tmr1 register pair value or the tmr3 register pair value. when a match occurs, the rc2/ccp1 (rc1/ccp2) pin is: ? driven high ? driven low ? toggle output (high to low or low to high) ? remains unchanged the action on the pin is based on the value of control bits ccp1m3:ccp1m0 (ccp2m3:ccp2m0). at the same time, interrupt flag bit ccp1if (ccp2if) is set. 13.4.1 ccp pin configuration the user must configure the ccpx pin as an output by clearing the appropriate trisc bit. 13.4.2 timer1/timer3 mode selection timer1 and/or timer3 must be running in timer mode or synchronized counter mode if the ccp module is using the compare feature. in asynchronous counter mode, the compare operation may not work. 13.4.3 software interrupt mode when generate software interrupt is chosen, the ccp1 pin is not affected. only a ccp interrupt is generated (if enabled). 13.4.4 special event trigger in this mode, an internal hardware trigger is generated, which may be used to initiate an action. the special event trigger output of ccp1 resets the tmr1 register pair. this allows the ccpr1 register to effectively be a 16-bit programmable period register for timer1. the special trigger output of ccpx resets either the tmr1 or tmr3 register pair. additionally, the ccp2 special event trigger will start an a/d conversion if the a/d module is enabled. figure 13-2: compare mode operation block diagram note: clearing the ccp1con register will force the rc2/ccp1 compare output latch to the default low level. this is not the data latch. note: the special event trigger from the ccp2 module will not set the timer1 or timer3 interrupt flag bits. ccpr1h ccpr1l tmr1h tmr1l comparator qs r output logic special event trigger set flag bit ccp1if match rc2/ccp1 trisc<2> ccp1con<3:0> mode select output enable pin special event trigger will: reset timer1or timer3, but not set timer1 or timer3 interrupt flag bit, and set bit go/done (adcon0<2>) which starts an a/d conversion (ccp2 only) tmr3h tmr3l t3ccp2 ccpr2h ccpr2l comparator 1 0 t3ccp2 t3ccp1 qs r output logic special event trigger set flag bit ccp2if match rc1/ccp2 trisc<1> ccp2con<3:0> mode select output enable pin 01
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 113 table 13-3: registers associated with capture, compare, timer1 and timer3 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif ( 1 ) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie ( 1 ) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip ( 1 ) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 trisc portc data direction register 1111 1111 1111 1111 tmr1l holding register for the least significant byte of the 16-bit tmr1 register xxxx xxxx uuuu uuuu tmr1h holding register for the most significant byte of the 16-bit tmr1register xxxx xxxx uuuu uuuu t1con t1ckps1 t1ckps0 t1oscen t1sync tmr1cs tmr1on --00 0000 --uu uuuu ccpr1l capture/compare/pwm register1 (lsb) xxxx xxxx uuuu uuuu ccpr1h capture/compare/pwm register1 (msb) xxxx xxxx uuuu uuuu ccp1con dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 --00 0000 --00 0000 ccpr2l capture/compare/pwm register2 (lsb) xxxx xxxx uuuu uuuu ccpr2h capture/compare/pwm register2 (msb) xxxx xxxx uuuu uuuu ccp2con dc2b1 dc2b0 ccp2m3 ccp2m2 ccp2m1 ccp2m0 --00 0000 --00 0000 pir2 bclif lv d i f tmr3if ccp2if 0000 0000 0000 0000 pie2 bclie lv d i e tmr3ie ccp2ie 0000 0000 0000 0000 ipr2 bclip lv d i p tmr3ip ccp2ip 0000 0000 0000 0000 tmr3l holding register for the least significant byte of the 16-bit tmr3 register xxxx xxxx uuuu uuuu tmr3h holding register for the most significant byte of the 16-bit tmr3 register xxxx xxxx uuuu uuuu t3con t3ckps2 t3ckps1 t3ckps0 t3ccp1 t3sync tmr3cs tmr3on -000 0000 -uuu uuuu legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by capture and timer1. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ds39026b-page 114 preliminary ? 7/99 microchip technology inc. 13.5 pwm mode in pulse width modulation (pwm) mode, the ccp1 pin produces up to a 10-bit resolution pwm output. since the ccp1 pin is multiplexed with the portc data latch, the trisc<2> bit must be cleared to make the ccp1 pin an output. figure 13-3 shows a simplified block diagram of the ccp module in pwm mode. for a step by step procedure on how to set up the ccp module for pwm operation, see section 13.5.3. figure 13-3: simplified pwm block diagram a pwm output (figure 13-4) has a time base (period) and a time that the output stays high (duty cycle). the frequency of the pwm is the inverse of the period (1/period). figure 13-4: pwm output note: clearing the ccp1con register will force the ccp1 pwm output latch to the default low level. this is not the portc i/o data latch. ccpr1l ccpr1h (slave) comparator tmr2 comparator pr2 (note 1) r q s duty cycle registers ccp1con<5:4> clear timer, ccp1 pin and latch d.c. trisc<2> rc2/ccp1 note: 8-bit timer is concatenated with 2-bit internal q clock or 2 bits of the prescaler to create 10-bit time-base. period duty cycle tmr2 = pr2 tmr2 = duty cycle tmr2 = pr2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 115 13.5.1 pwm period the pwm period is specified by writing to the pr2 reg- ister. the pwm period can be calculated using the fol- lowing formula: pwm period = (pr2) + 1] ? 4 ? t osc ? (tmr2 prescale value) pwm frequency is defined as 1 / [pwm period]. when tmr2 is equal to pr2, the following three events occur on the next increment cycle: ? tmr2 is cleared ? the ccp1 pin is set (exception: if pwm duty cycle = 0%, the ccp1 pin will not be set) ? the pwm duty cycle is latched from ccpr1l into ccpr1h 13.5.2 pwm duty cycle the pwm duty cycle is specified by writing to the ccpr1l register and to the ccp1con<5:4> bits. up to 10-bit resolution is available. the ccpr1l contains the eight msbs and the ccp1con<5:4> contains the two lsbs. this 10-bit value is represented by ccpr1l:ccp1con<5:4>. the following equation is used to calculate the pwm duty cycle in time: pwm duty cycle = (ccpr1l:ccp1con<5:4>) ? t osc ? (tmr2 prescale value) ccpr1l and ccp1con<5:4> can be written to at any time, but the duty cycle value is not latched into ccpr1h until after a match between pr2 and tmr2 occurs (i.e., the period is complete). in pwm mode, ccpr1h is a read-only register. the ccpr1h register and a 2-bit internal latch are used to double buffer the pwm duty cycle. this double buffering is essential for glitchless pwm operation. when the ccpr1h and 2-bit latch match tmr2 con- catenated with an internal 2-bit q clock or 2 bits of the tmr2 prescaler, the ccp1 pin is cleared. maximum pwm resolution (bits) for a given pwm fre- quency: note: the timer2 postscaler (see section 10.0) is not used in the determination of the pwm frequency. the postscaler could be used to have a servo update rate at a dif- ferent frequency than the pwm output. note: if the pwm duty cycle value is longer than the pwm period, the ccp1 pin will not be cleared. f osc f pwm --------------- ? ?? log 2 () log ----------------------------- bits =
pic18cxx2 ds39026b-page 116 preliminary ? 7/99 microchip technology inc. 13.5.3 set-up for pwm operation the following steps should be taken when configuring the ccp module for pwm operation: 1. set the pwm period by writing to the pr2 regis- ter. 2. set the pwm duty cycle by writing to the ccpr1l register and ccp1con<5:4> bits. 3. make the ccp1 pin an output by clearing the trisc<2> bit. 4. set the tmr2 prescale value and enable timer2 by writing to t2con. 5. configure the ccp1 module for pwm operation. table 13-4: example pwm frequencies and resolutions at 40 mhz table 13-5: registers associated with pwm and timer2 pwm frequency 2.44 khz 9.76 khz 19.53 khz 39.06 khz 78.12 khz 208.3 khz timer prescaler (1, 4, 16) 16 4 1 1 1 1 pr2 value 0xff 0xff 0xff 0x3f 0x1f 0x17 maximum resolution (bits) 10 10 10 8 7 5.5 name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif ( 1 ) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie ( 1 ) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip ( 1 ) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 trisc portc data direction register 1111 1111 1111 1111 tmr2 timer2 modules register 0000 0000 0000 0000 pr2 timer2 modules period register 1111 1111 1111 1111 t2con toutps3 toutps2 toutps1 toutps0 tmr2on t2ckps1 t2ckps0 -000 0000 -000 0000 ccpr1l capture/compare/pwm register1 (lsb) xxxx xxxx uuuu uuuu ccpr1h capture/compare/pwm register1 (msb) xxxx xxxx uuuu uuuu ccp1con dc1b1 dc1b0 ccp1m3 ccp1m2 ccp1m1 ccp1m0 --00 0000 --00 0000 ccpr2l capture/compare/pwm register2 (lsb) xxxx xxxx uuuu uuuu ccpr2h capture/compare/pwm register2 (msb) xxxx xxxx uuuu uuuu ccp2con dc2b1 dc2b0 ccp2m3 ccp2m2 ccp2m1 ccp2m0 --00 0000 --00 0000 legend: x = unknown, u = unchanged, = unimplemented read as '0'. shaded cells are not used by pwm and timer2. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 117 14.0 master synchronous serial port (mssp) module 14.1 master ssp (mssp) module overview the master synchronous serial port (mssp) module is a serial interface useful for communicating with other peripheral or microcontroller devices. these peripheral devices may be serial eeproms, shift registers, dis- play drivers, a/d converters, etc. the mssp module can operate in one of two modes: ? serial peripheral interface (spi) ? inter-integrated circuit (i 2 c) - full master mode - slave mode (with general address call) the i 2 c interface supports the following modes in hard- ware: ?master mode ? multi-master mode ?slave mode
pic18cxx2 ds39026b-page 118 preliminary ? 7/99 microchip technology inc. 14.2 control registers the mssp module has three associated registers. these include a status register and two control regis- ters. register 14-1: sspstat: mssp status register r/w-0 r/w-0 r-0 r-0 r-0 r-0 r-0 r-0 smp cke d/a psr/w ua bf bit 7 bit 0 bit 7 smp: sample bit spi master mode 1 = input data sampled at end of data output time 0 = input data sampled at middle of data output time spi slave mode smp must be cleared when spi is used in slave mode in i 2 c master or slave mode: 1 = slew rate control disabled for standard speed mode (100 khz and 1 mhz) 0 = slew rate control enabled for high speed mode (400 khz) bit 6 cke: spi clock edge select ckp = 0 1 = data transmitted on rising edge of sck 0 = data transmitted on falling edge of sck ckp = 1 1 = data transmitted on falling edge of sck 0 = data transmitted on rising edge of sck bit 5 d/a : data/address bit (i 2 c mode only) 1 = indicates that the last byte received or transmitted was data 0 = indicates that the last byte received or transmitted was address bit 4 p: stop bit (i 2 c mode only. this bit is cleared when the mssp module is disabled, sspen is cleared) 1 = indicates that a stop bit has been detected last (this bit is '0' on reset) 0 = stop bit was not detected last bit 3 s: start bit (i 2 c mode only. this bit is cleared when the mssp module is disabled, sspen is cleared) 1 = indicates that a start bit has been detected last (this bit is '0' on reset) 0 = start bit was not detected last bit 2 r/w : read/write bit information (i 2 c mode only) this bit holds the r/w bit information following the last address match. this bit is only valid from the address match to the next start bit, stop bit, or not ack bit. in i 2 c slave mode: 1 = read 0 = write in i 2 c master mode: 1 = transmit is in progress 0 = transmit is not in progress. or-ing this bit with sen, rsen, pen, rcen, or acken will indicate if the mssp is in idle mode. bit 1 ua: update address (10-bit i 2 c mode only) 1 = indicates that the user needs to update the address in the sspadd register 0 = address does not need to be updated bit 0 bf: buffer full status bit receive (spi and i 2 c modes) 1 = receive complete, sspbuf is full 0 = receive not complete, sspbuf is empty transmit (i 2 c mode only) 1 = data transmit in progress (does not include the ack and stop bits), sspbuf is full 0 = data transmit complete (does not include the ack and stop bits), sspbuf is empty legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 119 register 14-2: sspcon1: mssp control register1 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 bit 7 bit 0 bit 7 wcol: write collision detect bit master mode: 1 = a write to the sspbuf register was attempted while the i 2 c conditions were not valid for a transmission to be started 0 = no collision slave mode: 1 = the sspbuf register is written while it is still transmitting the previous word must be cleared in software) 0 = no collision bit 6 sspov: receive overflow indicator bit in spi mode: 1 = a new byte is received while the sspbuf register is still holding the previous data. in case of overflow, the data in sspsr is lost. overflow can only occur in slave mode. in slave mode the user must read the sspbuf, even if only transmitting data, to avoid setting overflow. in master mode the overflow bit is not set since each new reception (and transmission) is initiated by writing to the sspbuf register. (must be cleared in software) 0 = no overflow in i 2 c mode: 1 = a byte is received while the sspbuf register is still holding the previous byte. sspov is a "dont care" in transmit mode. (must be cleared in software) 0 = no overflow bit 5 sspen: synchronous serial port enable bit in both modes, when enabled, these pins must be properly configured as input or output. in spi mode: 1 = enables serial port and configures sck, sdo, sdi, and ss as the source of the serial port pins 0 = disables serial port and configures these pins as i/o port pins in i 2 c mode: 1 = enables the serial port and configures the sda and scl pins as the source of the serial port pins 0 = disables serial port and configures these pins as i/o port pins bit 4 ckp: clock polarity select bit in spi mode: 1 = idle state for clock is a high level 0 = idle state for clock is a low level in i 2 c slave mode: sck release control 1 = enable clock 0 = holds clock low (clock stretch) (used to ensure data setup time) in i 2 c master mode unused in this mode bit 3 - 0 sspm3:sspm0: synchronous serial port mode select bits 0000 = spi master mode, clock = f osc /4 0001 = spi master mode, clock = f osc /16 0010 = spi master mode, clock = f osc /64 0011 = spi master mode, clock = tmr2 output/2 0100 = spi slave mode, clock = sck pin. ss pin control enabled. 0101 = spi slave mode, clock = sck pin. ss pin control disabled. ss can be used as i/o pin 0110 = i 2 c slave mode, 7-bit address 0111 = i 2 c slave mode, 10-bit address 1000 = i 2 c master mode, clock = f osc / (4 * (sspadd+1) ) 1001 = reserved 1010 = reserved 1011 = i 2 c firmware controlled master mode (slave idle) 1100 = reserved 1101 = reserved 1110 = i 2 c slave mode, 7-bit address with start and stop bit interrupts enabled 1111 = i 2 c slave mode, 10-bit address with start and stop bit interrupts enabled legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 120 preliminary ? 7/99 microchip technology inc. register 14-3: sspcon2: mssp control register2 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 gcen ackstat ackdt acken rcen pen rsen sen bit 7 bit 0 bit 7 gcen: general call enable bit (in i 2 c slave mode only) 1 = enable interrupt when a general call address (0000h) is received in the sspsr 0 = general call address disabled bit 6 ackstat: acknowledge status bit (in i 2 c master mode only) in master transmit mode: 1 = acknowledge was not received from slave 0 = acknowledge was received from slave bit 5 ackdt: acknowledge data bit (in i 2 c master mode only) in master receive mode: value that will be transmitted when the user initiates an acknowledge sequence at the end of a receive. 1 = not acknowledge 0 = acknowledge bit 4 acken: acknowledge sequence enable bit (in i 2 c master mode only) in master receive mode: 1 = initiate acknowledge sequence on sda and scl pins, and transmit ackdt data bit. automatically cleared by hardware. 0 = acknowledge sequence idle bit 3 rcen: receive enable bit (in i 2 c master mode only) 1 = enables receive mode for i 2 c 0 = receive idle bit 2 pen: stop condition enable bit (in i 2 c master mode only) sck release control 1 = initiate stop condition on sda and scl pins. automatically cleared by hardware. 0 = stop condition idle bit 1 rsen: repeated start condition enabled bit (in i 2 c master mode only) 1 = initiate repeated start condition on sda and scl pins. automatically cleared by hardware. 0 = repeated start condition idle. bit 0 sen: start condition enabled bit (in i 2 c master mode only) 1 = initiate start condition on sda and scl pins. automatically cleared by hardware. 0 = start condition idle note: for bits acken, rcen, pen, rsen, sen: if the i 2 c module is not in the idle mode, this bit may not be set (no spooling) and the sspbuf may not be written (or writes to the sspbuf are disabled). legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 121 14.2.1 spi mode the spi mode allows 8-bits of data to be synchro- nously transmitted and received simultaneously. all four modes of spi are supported. to accomplish com- munication, typically three pins are used: ? serial data out (sdo) - rc5/sdo ? serial data in (sdi) - rc4/sdi/sda ? serial clock (sck) - rc3/sck/scl/lvoin additionally a fourth pin may be used when in a slave mode of operation: ?slave select (ss ) - ra5/ss /an4 14.2.1.1 operation when initializing the spi, several options need to be specified. this is done by programming the appropriate control bits (sspcon1<5:0>) and sspstat<7:6>. these control bits allow the following to be specified: ? master mode (sck is the clock output) ? slave mode (sck is the clock input) ? clock polarity (idle state of sck) ? data input sample phase (middle or end of data output time) ? clock edge (output data on rising/falling edge of sck) ? clock rate (master mode only) ? slave select mode (slave mode only) figure 14-1 shows the block diagram of the mssp module, when in spi mode. figure 14-1: mssp block diagram (spi mode) the mssp consists of a transmit/receive shift register (sspsr) and a buffer register (sspbuf). the sspsr shifts the data in and out of the device, msb first. the sspbuf holds the data that was written to the sspsr, until the received data is ready. once the 8 bits of data have been received, that byte is moved to the sspbuf register. then the buffer full detect bit, bf (sspstat<0>), and the interrupt flag bit, sspif, are set. this double buffering of the received data (ssp- buf) allows the next byte to start reception before reading the data that was just received. any write to the sspbuf register during transmission/reception of data will be ignored, and the write collision detect bit, wcol (sspcon1<7>), will be set. user software must clear the wcol bit so that it can be determined if the follow- ing write(s) to the sspbuf register completed suc- cessfully. read write internal data bus sspsr reg sspbuf reg sspm3:sspm0 bit0 shift clock ss control enable edge select clock select tmr2 output t osc prescaler 4, 16, 64 2 edge select 2 4 data to tx/rx in sspsr tris bit 2 smp:cke sdi sdo ss sck ( )
pic18cxx2 ds39026b-page 122 preliminary ? 7/99 microchip technology inc. when the application software is expecting to receive valid data, the sspbuf should be read before the next byte of data to transfer is written to the sspbuf. buffer full bit, bf (sspstat<0>), indicates when sspbuf has been loaded with the received data (transmission is complete). when the sspbuf is read, the bf bit is cleared. this data may be irrelevant if the spi is only a transmitter. generally the mssp interrupt is used to determine when the transmission/reception has completed. the sspbuf must be read and/or written. if the interrupt method is not going to be used, then software polling can be done to ensure that a write collision does not occur. example 14-1 shows the loading of the sspbuf (sspsr) for data transmission. example 14-1: loading the sspbuf (sspsr) register the sspsr is not directly readable or writable, and can only be accessed by addressing the sspbuf register. additionally, the mssp status register (sspstat) indi- cates the various status conditions. 14.2.1.2 enabling spi i/o to enable the serial port, ssp enable bit, sspen (sspcon1<5>), must be set. to reset or reconfigure spi mode, clear the sspen bit, re-initialize the ssp- con registers, and then set the sspen bit. this con- figures the sdi, sdo, sck, and ss pins as serial port pins. for the pins to behave as the serial port function, some must have their data direction bits (in the tris register) appropriately programmed. that is: ? sdi is automatically controlled by the spi module ? sdo must have trisc<5> bit cleared ? sck (master mode) must have trisc<3> bit cleared ? sck (slave mode) must have trisc<3> bit set ?ss must have trisc<4> bit set any serial port function that is not desired may be over- ridden by programming the corresponding data direc- tion (tris) register to the opposite value. 14.2.1.3 typical connection figure 14-2 shows a typical connection between two microcontrollers. the master controller (processor 1) initiates the data transfer by sending the sck signal. data is shifted out of both shift registers on their pro- grammed clock edge, and latched on the opposite edge of the clock. both processors should be programmed to same clock polarity (ckp), then both controllers would send and receive data at the same time. whether the data is meaningful (or dummy data) depends on the application software. this leads to three scenarios for data transmission: ? master sends data slave sends dummy data ? master sends data slave sends data ? master sends dummy data slave sends data loop btfss sspstat, bf ;has data been received (transmit complete)? goto loop ;no movf sspbuf, w ;wreg reg = contents of sspbuf movwf rxdata ;save in user ram, if data is meaningful movf txdata, w ;w reg = contents of txdata movwf sspbuf ;new data to xmit
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 123 figure 14-2: spi master/slave connection serial input buffer (sspbuf) shift register (sspsr) msb lsb sdo sdi processor 1 sck spi master sspm3:sspm0 = 00xxb serial input buffer (sspbuf) shift register (sspsr) lsb msb sdi sdo processor 2 sck spi slave sspm3:sspm0 = 010xb serial clock
pic18cxx2 ds39026b-page 124 preliminary ? 7/99 microchip technology inc. 14.2.1.4 master mode the master can initiate the data transfer at any time because it controls the sck. the master determines when the slave (processor 2, figure 14-2) is to broad- cast data by the software protocol. in master mode the data is transmitted/received as soon as the sspbuf register is written to. if the spi is only going to receive, the sdo output could be disabled (programmed as an input). the sspsr register will continue to shift in the signal present on the sdi pin at the programmed clock rate. as each byte is received, it will be loaded into the sspbuf register as if a normal received byte (interrupts and status bits appropriately set). this could be useful in receiver applications as a line activity monitor mode. the clock polarity is selected by appropriately program- ming the ckp bit (sspcon1<4>). this then would give waveforms for spi communication as shown in figure 14-3, figure 14-5, and figure 14-6 where the msb is transmitted first. in master mode, the spi clock rate (bit rate) is user programmable to be one of the fol- lowing: ?f osc /4 (or t cy ) ?f osc /16 (or 4 ? t cy ) ?f osc /64 (or 16 ? t cy ) ? timer2 output/2 this allows a maximum data rate (at 40 mhz) of 10.00 mbps. figure 14-3 shows the waveforms for master mode. when the cke bit is set, the sdo data is valid before there is a clock edge on sck. the change of the input sample is shown based on the state of the smp bit. the time when the sspbuf is loaded with the received data is shown. figure 14-3: spi mode waveform (master mode) sck (ckp = 0 sck (ckp = 1 sck (ckp = 0 sck (ckp = 1 4 clock modes input sample input sample sdi bit7 bit0 sdo bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit7 bit0 sdi sspif (smp = 1) (smp = 0) (smp = 1) cke = 1) cke = 0) cke = 1) cke = 0) (smp = 0) write to sspbuf sspsr to sspbuf sdo bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 (cke = 0) (cke = 1) next q4 cycle after q2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 125 14.2.1.5 slave mode in slave mode, the data is transmitted and received as the external clock pulses appear on sck. when the last bit is latched, the sspif interrupt flag bit is set. while in slave mode the external clock is supplied by the external clock source on the sck pin. this external clock must meet the minimum high and low times as specified in the electrical specifications. while in sleep mode, the slave can transmit/receive data. when a byte is receive the device will wake-up from sleep. 14.2.1.6 slave select synchronization the ss pin allows a synchronous slave mode. the spi must be in slave mode with ss pin control enabled (sspcon1<3:0> = 04h). the pin must not be driven low for the ss pin to function as an input. the data latch must be high. when the ss pin is low, transmission and reception are enabled and the sdo pin is driven. when the ss pin goes high, the sdo pin is no longer driven, even if in the mid- dle of a transmitted byte, and becomes a floating output. external pull-up/ pull-down resistors may be desirable, depending on the application. when the spi module resets, the bit counter is forced to 0. this can be done by either by forcing the ss pin to a high level or clearing the sspen bit. to emulate two-wire communication, the sdo pin can be connected to the sdi pin. when the spi needs to operate as a receiver the sdo pin can be configured as an input. this disables transmissions from the sdo. the sdi can always be left as an input (sdi function) since it cannot create a bus conflict. figure 14-4: slave synchronization waveform note 1: when the spi is in slave mode with ss pin control enabled, (sspcon<3:0> = 0100 ) the spi module will reset if the ss pin is set to v dd . note 2: if the spi is used in slave mode with cke set, then the ss pin control must be enabled. sck (ckp = 1 sck (ckp = 0 input sample sdi bit7 sdo bit7 bit6 bit7 sspif interrupt (smp = 0) cke = 0) cke = 0) (smp = 0) write to sspbuf sspsr to sspbuf ss flag bit0 bit7 bit0 next q4 cycle after q2
pic18cxx2 ds39026b-page 126 preliminary ? 7/99 microchip technology inc. figure 14-5: spi mode waveform (slave mode with cke = 0) figure 14-6: spi mode waveform (slave mode with cke = 1) sck (ckp = 1 sck (ckp = 0 input sample sdi bit7 bit0 sdo bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sspif interrupt (smp = 0) cke = 0) cke = 0) (smp = 0) write to sspbuf sspsr to sspbuf ss flag optional next q4 cycle after q2 sck (ckp = 1 sck (ckp = 0 input sample sdi bit7 bit0 sdo bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 sspif interrupt (smp = 0) cke = 1) cke = 1) (smp = 0) write to sspbuf sspsr to sspbuf ss flag not optional next q4 cycle after q2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 127 14.2.1.7 sleep operation in master mode all module clocks are halted, and the transmission/reception will remain in that state until the device wakes from sleep. after the device returns to normal mode, the module will continue to transmit/ receive data. in slave mode, the spi transmit/receive shift register operates asynchronously to the device. this allows the device to be placed in sleep mode, and data to be shifted into the spi transmit/receive shift register. when all 8-bits have been received, the mssp interrupt flag bit will be set and if enabled will wake the device from sleep. 14.2.1.8 effects of a reset a reset disables the mssp module and terminates the current transfer. 14.2.1.9 bus mode compatibility table 14-1 shows the compatibility between the stan- dard spi modes and the states the the ckp and cke control bits. table 14-1: spi bus modes there is also a smp bit which controls when the data is sampled. standard spi mode terminology control bits state ckp cke 0, 0 0 1 0, 1 0 0 1, 0 1 1 1, 1 1 0
pic18cxx2 ds39026b-page 128 preliminary ? 7/99 microchip technology inc. table 14-2: registers associated with spi operation 14.3 mssp i 2 c operation the mssp module in i 2 c mode fully implements all master and slave functions (including general call sup- port) and provides interrupts on start and stop bits in hardware to determine a free bus (multi-master func- tion). the mssp module implements the standard mode specifications, as well as 7-bit and 10-bit addressing. two pins are used for data transfer. these are the rc3/ sck/scl pin, which is the clock (scl), and the rc4/ sdi/sda pin, which is the data (sda). the user must configure these pins as inputs or outputs through the trisc<4:3> bits. the mssp module functions are enabled by setting mssp enable bit sspen (sspcon<5>). figure 14-7: mssp block diagram (i 2 c mode) the mssp module has six registers for i 2 c operation. these are the: ? mssp control register1 (sspcon1) ? mssp control register2 (sspcon2) ? mssp status register (sspstat) ? serial receive/transmit buffer (sspbuf) ? mssp shift register (sspsr) - not directly accessible ? mssp address register (sspadd) name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif ( 1 ) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie ( 1 ) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip ( 1 ) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 trisc portc data direction register 1111 1111 1111 1111 sspbuf synchronous serial port receive buffer/transmit register xxxx xxxx uuuu uuuu sspcon wcol sspov sspen ckp sspm3 sspm2 sspm1 sspm0 0000 0000 0000 0000 trisa porta data direction register --11 1111 --11 1111 sspstat smp cke d/a p s r/w ua bf 0000 0000 0000 0000 legend: x = unknown, u = unchanged, - = unimplemented read as '0'. shaded cells are not used by the mssp in spi mode. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear. read write sspsr reg match detect sspadd reg start and stop bit detect sspbuf reg internal data bus addr match set, reset s, p bits (sspstat reg) rc3/sck/scl rc4/ shift clock msb sdi/ lsb sda
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 129 the sspcon1 register allows control of the i 2 c oper- ation. four mode selection bits (sspcon<3:0>) allow one of the following i 2 c modes to be selected: ?i 2 c master mode, clock = osc/4 (sspadd +1) ?i 2 c slave mode (7-bit address) ?i 2 c slave mode (10-bit address) ?i 2 c slave mode (7-bit address), with start and stop bit interrupts enabled ?i 2 c slave mode (10-bit address), with start and stop bit interrupts enabled ?i 2 c firmware controlled master operation, slave is idle selection of any i 2 c mode, with the sspen bit set, forces the scl and sda pins to be open drain, pro- vided these pins are programmed to inputs by setting the appropriate trisc bits. 14.3.1 slave mode in slave mode, the scl and sda pins must be config- ured as inputs (trisc<4:3> set). the mssp module will override the input state with the output data when required (slave-transmitter). when an address is matched or the data transfer after an address match is received, the hardware automati- cally will generate the acknowledge (ack ) pulse and load the sspbuf register with the received value cur- rently in the sspsr register. there are certain conditions that will cause the mssp module not to give this ack pulse. these are if either (or both): a) the buffer full bit bf (sspstat<0>) was set before the transfer was received. b) the overflow bit sspov (sspcon<6>) was set before the transfer was received. in this case, the sspsr register value is not loaded into the sspbuf, but bit sspif (pir1<3>) is set. the bf bit is cleared by reading the sspbuf register, while bit sspov is cleared through software. the scl clock input must have a minimum high and low for proper operation. the high and low times of the i 2 c specification, as well as the requirement of the mssp module, is shown in timing parameter #100 and parameter #101. 14.3.1.1 addressing once the mssp module has been enabled, it waits for a start condition to occur. following the start con- dition, the 8-bits are shifted into the sspsr register. all incoming bits are sampled with the rising edge of the clock (scl) line. the value of register sspsr<7:1> is compared to the value of the sspadd register. the address is compared on the falling edge of the eighth clock (scl) pulse. if the addresses match, and the bf and sspov bits are clear, the following events occur: a) the sspsr register value is loaded into the sspbuf register. b) the buffer full bit bf is set. c) an ack pulse is generated. d) mssp interrupt flag bit sspif (pir1<3>) is set (interrupt is generated if enabled) on the falling edge of the ninth scl pulse. in 10-bit address mode, two address bytes need to be received by the slave. the five most significant bits (msbs) of the first address byte specify if this is a 10-bit address. bit r/w (sspstat<2>) must specify a write so the slave device will receive the second address byte. for a 10-bit address, the first byte would equal 1111 0 a9 a8 0, where a9 and a8 are the two msbs of the address. the sequence of events for 10-bit address is as follows with steps 7- 9 for slave-transmit- ter: 1. receive first (high) byte of address (bits sspif, bf and bit ua (sspstat<1>) are set). 2. update the sspadd register with second (low) byte of address (clears bit ua and releases the scl line). 3. read the sspbuf register (clears bit bf) and clear flag bit sspif. 4. receive second (low) byte of address (bits sspif, bf, and ua are set). 5. update the sspadd register with the first (high) byte of address. if match releases scl line, this will clear bit ua. 6. read the sspbuf register (clears bit bf) and clear flag bit sspif. 7. receive repeated start condition. 8. receive first (high) byte of address (bits sspif and bf are set). 9. read the sspbuf register (clears bit bf) and clear flag bit sspif.
pic18cxx2 ds39026b-page 130 preliminary ? 7/99 microchip technology inc. 14.3.1.2 reception when the r/w bit of the address byte is clear and an address match occurs, the r/w bit of the sspstat register is cleared. the received address is loaded into the sspbuf register. when the address byte overflow condition exists, then no acknowledge (ack ) pulse is given. an overflow con- dition is defined as either bit bf (sspstat<0>) is set or bit sspov (sspcon<6>) is set. an mssp interrupt is generated for each data transfer byte. flag bit sspif (pir1<3>) must be cleared in soft- ware. the sspstat register is used to determine the status of the byte. 14.3.1.3 transmission when the r/w bit of the incoming address byte is set and an address match occurs, the r/w bit of the sspstat register is set. the received address is loaded into the sspbuf register. the ack pulse will be sent on the ninth bit and pin rc3/sck/scl is held low. the transmit data must be loaded into the ssp- buf register, which also loads the sspsr register. then pin rc3/sck/scl should be enabled by setting bit ckp (sspcon<4>). the master must monitor the scl pin prior to asserting another clock pulse. the slave devices may be holding off the master by stretch- ing the clock. the eight data bits are shifted out on the falling edge of the scl input. this ensures that the sda signal is valid during the scl high time (figure 14-9). an mssp interrupt is generated for each data transfer byte. the sspif bit must be cleared in software and the sspstat register is used to determine the status of the byte. the sspif bit is set on the falling edge of the ninth clock pulse. as a slave-transmitter, the ack pulse from the mas- ter-receiver is latched on the rising edge of the ninth scl input pulse. if the sda line is high (not ack ), then the data transfer is complete. when the ack is latched by the slave, the slave logic is reset (resets sspstat register) and the slave monitors for another occurrence of the start bit. if the sda line was low (ack ), the transmit data must be loaded into the sspbuf register, which also loads the sspsr register. pin rc3/sck/scl should be enabled by setting bit ckp. figure 14-8: i 2 c slave mode waveforms for reception (7-bit address) figure 14-9: i 2 c slave mode waveforms for transmission (7-bit address) p 9 8 7 6 5 d0 d1 d2 d3 d4 d5 d6 d7 s a7 a6 a5 a4 a3 a2 a1 sda scl 123456 789 1234 56 7 89 1234 bus master terminates transfer bit sspov is set because the sspbuf register is still full. cleared in software sspbuf register is read ack receiving data receiving data d0 d1 d2 d3 d4 d5 d6 d7 ack r/w =0 receiving address sspif bf (sspstat<0>) sspov (sspcon1<6>) not ack ack is not sent. sda scl sspif bf (sspstat<0>) ckp (sspcon1<4>) a7 a6 a5 a4 a3 a2 a1 ack d7 d6 d5 d4 d3 d2 d1 d0 not ack transmitting data r/w = 1 receiving address 123456789 123456789 p cleared in software sspbuf is written in software from ssp interrupt service routine set bit after writing to sspbuf s data in sampled scl held low while cpu responds to sspif (the sspbuf must be written-to before the ckp bit can be set) r/w = 0
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 131 figure 14-10: i 2 c slave mode waveform (transmission 10-bit address) sda scl sspif bf (sspstat<0>) s 1 234 56 7 89 1 2345 67 89 1 2345 7 89 p 1 111 0a9a8 a7 a6a5a4a3a2a1a0 11110 a8 r/w =1 ack ack r/w = 0 ack receive first byte of address cleared in software master sends nack a9 6 (pir1<3>) receive second byte of address cleared by hardware when sspadd is updated. ua (sspstat<1>) clock is held low until update of sspadd has taken place ua is set indicating that the sspadd needs to be updated ua is set indicating that sspadd needs to be updated cleared by hardware when sspadd is updated. sspbuf is written with contents of sspsr dummy read of sspbuf to clear bf flag receive first byte of address 12345 789 d7 d6 d5 d4 d3 d1 ack d2 6 transmitting data byte d0 dummy read of sspbuf to clear bf flag sr cleared in software write of sspbuf initiates transmit cleared in software transmit is complete ckp has to be set for clock to be released bus master terminates transfer
pic18cxx2 ds39026b-page 132 preliminary ? 7/99 microchip technology inc. figure 14-11: i 2 c slave mode waveform (reception 10-bit address) sda scl sspif bf (sspstat<0>) s 1 234 56 7 89 1 2345 67 89 1 2345 7 89 p 1 1 1 1 0 a9a8 a7 a6a5a4a3a2a1 a0 d7d6d5d4d3 d1d0 receive data byte ack r/w = 0 ack receive first byte of address cleared in software bus master terminates transfer d2 6 (pir1<3>) receive second byte of address cleared by hardware when sspadd is updated with ua (sspstat<1>) clock is held low until update of sspadd has taken place ua is set indicating that the sspadd needs to be updated ua is set indicating that sspadd needs to be updated sspbuf is written with contents of sspsr dummy read of sspbuf to clear bf flag ack r/w = 1 cleared in software dummy read of sspbuf to clear bf flag read of sspbuf clears bf flag cleared by hardware when sspadd is updated with low byte of address. high byte of address.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 133 14.3.2 general call address support the addressing procedure for the i 2 c bus is such that the first byte after the start condition usually deter- mines which device will be the slave addressed by the master. the exception is the general call address which can address all devices. when this address is used, all devices should, in theory, respond with an acknowl- edge. the general call address is one of eight addresses reserved for specific purposes by the i 2 c protocol. it consists of all 0s with r/w = 0. the general call address is recognized when the gen- eral call enable bit (gcen) is enabled (sspcon2<7> set). following a start-bit detect, 8-bits are shifted into the sspsr and the address is compared against the sspadd. it is also compared to the general call address and fixed in hardware. if the general call address matches, the sspsr is transferred to the sspbuf, the bf flag bit is set (eight bit), and on the falling edge of the ninth bit (ack bit), the sspif interrupt flag bit is set. when the interrupt is serviced, the source for the inter- rupt can be checked by reading the contents of the sspbuf. the value can be used to determine if the address was device specific or a general call address. in 10-bit mode, the sspadd is required to be updated for the second half of the address to match, and the ua bit is set (sspstat<1>). if the general call address is sampled when the gcen bit is set, while the slave is configured in 10-bit address mode, then the second half of the address is not necessary, the ua bit will not be set, and the slave will begin receiving data after the acknowledge (figure 14-12). figure 14-12: slave mode general call address sequence (7 or 10-bit address mode) sda scl s sspif bf (sspstat<0>) sspov (sspcon1<6>) cleared in software sspbuf is read r/w = 0 ack general call address address is compared to general call address gcen (sspcon2<7>) receiving data ack 123456789123456789 d7 d6 d5 d4 d3 d2 d1 d0 after ack, set interrupt '0' '1'
pic18cxx2 ds39026b-page 134 preliminary ? 7/99 microchip technology inc. 14.3.3 master mode master mode of operation is supported by interrupt generation on the detection of the start and stop conditions. the stop (p) and start (s) bits are cleared from a reset or when the mssp module is dis- abled. control of the i 2 c bus may be taken when the p bit is set or the bus is idle with both the s and p bits clear. in master mode, the scl and sda lines are manipu- lated by the mssp hardware. the following events will cause ssp interrupt flag bit, sspif, to be set (ssp interrupt if enabled): ? start condition ? stop condition ? data transfer byte transmitted/received ? acknowledge transmit ? repeated start 14.3.4 i 2 c master mode support master mode is enabled by setting and clearing the appropriate sspm bits in sspcon1 and by setting the sspen bit. once master mode is enabled, the user has six options. 1. assert a start condition on sda and scl. 2. assert a repeated start condition on sda and scl. 3. write to the sspbuf register initiating transmis- sion of data/address. 4. generate a stop condition on sda and scl. 5. configure the i 2 c port to receive data. 6. generate an acknowledge condition at the end of a received byte of data. figure 14-13: mssp block diagram (i 2 c master mode) note: the mssp module, when configured in i 2 c master mode, does not allow queueing of events. for instance, the user is not allowed to initiate a start condition and immediately write the sspbuf register to imitate transmission before the start condition is complete. in this case, the sspbuf will not be written to and the wcol bit will be set, indicating that a write to the sspbuf did not occur. read write sspsr start bit, stop bit, start bit detect sspbuf internal data bus set/reset, s, p, wcol (sspstat) shift clock msb lsb sda acknowledge generate stop bit detect write collision detect clock arbitration state counter for end of xmit/rcv scl scl in bus collision sda in receive enable clock cntl clock arbitrate/wcol detect (hold off clock source) sspadd<6:0> baud set sspif, bclif reset ackstat, pen (sspcon2) rate generator sspm3:sspm0
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 135 14.3.4.1 i 2 c master mode operation the master device generates all of the serial clock pulses and the start and stop conditions. a trans- fer is ended with a stop condition or with a repeated start condition. since the repeated start condition is also the beginning of the next serial transfer, the i 2 c bus will not be released. in master transmitter mode serial data is output through sda, while scl outputs the serial clock. the first byte transmitted contains the slave address of the receiving device (7 bits) and the read/write (r/w ) bit. in this case, the r/w bit will be logic '0'. serial data is trans- mitted 8 bits at a time. after each byte is transmitted, an acknowledge bit is received. start and stop condi- tions are output to indicate the beginning and the end of a serial transfer. in master receive mode, the first byte transmitted con- tains the slave address of the transmitting device (7 bits) and the r/w bit. in this case, the r/w bit will be logic '1'. thus, the first byte transmitted is a 7-bit slave address followed by a '1' to indicate receive bit. serial data is received via sda, while scl outputs the serial clock. serial data is received 8 bits at a time. after each byte is received, an acknowledge bit is transmitted. start and stop conditions indicate the beginning and end of transmission. the baud rate generator used for the spi mode opera- tion is now used to set the scl clock frequency for either 100 khz, 400 khz or 1 mhz i 2 c operation. the baud rate generator reload value is contained in the lower 7 bits of the sspadd register. the baud rate gen- erator will automatically begin counting on a write to the sspbuf. once the given operation is complete, (i.e. transmission of the last data bit is followed by ack), the internal clock will automatically stop counting and the scl pin will remain in its last state. a typical transmit sequence would go as follows: a) the user generates a start condition by setting the start enable bit sen (sspcon2<0>). b) sspif is set. the mssp module will wait the required start time before any other operation takes place. c) the user loads the sspbuf with the address to transmit. d) address is shifted out the sda pin until all 8 bits are transmitted. e) the mssp module shifts in the ack bit from the slave device and writes its value into the sspcon2 register (sspcon2<6>). f) the mssp module generates an interrupt at the end of the ninth clock cycle by setting the sspif bit. g) the user loads the sspbuf with eight bits of data. h) data is shifted out the sda pin until all 8 bits are transmitted. i) the mssp module shifts in the ack bit from the slave device and writes its value into the sspcon2 register (sspcon2<6>). j) the mssp module generates an interrupt at the end of the ninth clock cycle by setting the sspif bit. k) the user generates a stop condition by setting the stop enable bit pen (sspcon2<2>). l) interrupt is generated once the stop condition is complete.
pic18cxx2 ds39026b-page 136 preliminary ? 7/99 microchip technology inc. 14.3.5 baud rate generator in i 2 c master mode, the reload value for the brg is located in the lower 7 bits of the sspadd register (figure 14-14). when the brg is loaded with this value, the brg counts down to 0 and stops until another reload has taken place. the brg count is dec- remented twice per instruction cycle (t cy ) on the q2 and q4 clocks. in i 2 c master mode, the brg is reloaded automatically. if clock arbitration is taking place for instance, the brg will be reloaded when the scl pin is sampled high (figure 14-15). figure 14-14: baud rate generator block diagram figure 14-15: baud rate generator timing with clock arbitration sspm3:sspm0 brg down counter clkout fosc/4 sspadd<6:0> sspm3:sspm0 scl reload control reload sda scl scl de-asserted but slave holds dx-1 dx brg scl is sampled high, reload takes place and brg starts its count. 03h 02h 01h 00h (hold off) 03h 02h reload brg value scl low (clock arbitration) scl allowed to transition high brg decrements on q2 and q4 cycles
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 137 14.3.6 i 2 c master mode start condition timing to initiate a start condition, the user sets the start condition enable bit sen (sspcon2<0>). if the sda and scl pins are sampled high, the baud rate genera- tor is re-loaded with the contents of sspadd<6:0> and starts its count. if scl and sda are both sampled high when the baud rate generator times out (t brg ), the sda pin is driven low. the action of the sda being driven low, while scl is high, is the start condition, and causes the s bit (sspstat<3>) to be set. follow- ing this, the baud rate generator is reloaded with the contents of sspadd<6:0> and resumes its count. when the baud rate generator times out (t brg ), the sen bit (sspcon2<0>) will be automatically cleared by hardware, the baud rate generator is suspended leaving the sda line held low and the start condition is complete. 14.3.6.1 wcol status flag if the user writes the sspbuf when an start sequence is in progress, the wcol is set and the con- tents of the buffer are unchanged (the write doesnt occur). figure 14-16: first start bit timing note: if at the beginning of the start condition, the sda and scl pins are already sam- pled low, or if during the start condition the scl line is sampled low before the sda line is driven low, a bus collision occurs, the bus collision interrupt flag bclif is set, the start condition is aborted, and the i 2 c module is reset into its idle state. note: because queueing of events is not allowed, writing to the lower 5 bits of sspcon2 is disabled until the start condition is complete. sda scl s t brg 1st bit 2nd bit t brg sda = 1, at completion of start bit, scl = 1 write to sspbuf occurs here t brg hardware clears sen bit t brg write to sen bit occurs here. set s bit (sspstat<3>) and sets sspif bit
pic18cxx2 ds39026b-page 138 preliminary ? 7/99 microchip technology inc. 14.3.7 i 2 c master mode repeated start condition timing a repeated start condition occurs when the rsen bit (sspcon2<1>) is programmed high and the i 2 c logic module is in the idle state. when the rsen bit is set, the scl pin is asserted low. when the scl pin is sam- pled low, the baud rate generator is loaded with the contents of sspadd<5:0> and begins counting. the sda pin is released (brought high) for one baud rate generator count (t brg ). when the baud rate generator times out, if sda is sampled high, the scl pin will be de-asserted (brought high). when scl is sampled high, the baud rate generator is re-loaded with the con- tents of sspadd<6:0> and begins counting. sda and scl must be sampled high for one t brg . this action is then followed by assertion of the sda pin (sda = 0) for one t brg, while scl is high. following this, the rsen bit (sspcon2<1>) will be automatically cleared and the baud rate generator will not be reloaded, leaving the sda pin held low. as soon as a start condition is detected on the sda and scl pins, the s bit (ssp- stat<3>) will be set. the sspif bit will not be set until the baud rate generator has timed-out. immediately following the sspif bit getting set, the user may write the sspbuf with the 7-bit address in 7-bit mode, or the default first address in 10-bit mode. after the first eight bits are transmitted and an ack is received, the user may then transmit an additional eight bits of address (10-bit mode) or eight bits of data (7-bit mode). 14.3.7.1 wcol status flag if the user writes the sspbuf when a repeated start sequence is in progress, the wcol is set and the con- tents of the buffer are unchanged (the write doesnt occur). figure 14-17: repeat start condition waveform note 1: if rsen is programmed while any other event is in progress, it will not take effect. note 2: a bus collision during the repeated start condition occurs if: ? sda is sampled low when scl goes from low to high. ? scl goes low before sda is asserted low. this may indicate that another master is attempting to transmit a data "1". note: because queueing of events is not allowed, writing of the lower 5 bits of sspcon2 is disabled until the repeated start condition is complete. sda scl sr = repeated start write to sspcon2 write to sspbuf occurs here. falling edge of ninth clock end of xmit at completion of start bit, hardware clear rsen bit 1st bit set s (sspstat<3>) t brg t brg sda = 1, sda = 1, scl(no change) scl = 1 occurs here. t brg t brg t brg and set sspif
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 139 14.3.8 i 2 c master mode transmission transmission of a data byte, a 7-bit address or the other half of a 10-bit address is accomplished by simply writ- ing a value to the sspbuf register. this action will set the buffer full flag bit, bf, and allow the baud rate gen- erator to begin counting and start the next transmis- sion. each bit of address/data will be shifted out onto the sda pin after the falling edge of scl is asserted (see data hold time specification parameter 106 ). scl is held low for one baud rate generator roll over count (t brg ). data should be valid before scl is released high (see data setup time specification parameter 107 ). when the scl pin is released high, it is held that way for t brg . the data on the sda pin must remain stable for that duration and some hold time after the next falling edge of scl. after the eighth bit is shifted out (the falling edge of the eighth clock), the bf flag is cleared and the master releases sda. allowing the slave device being addressed to respond with an ack bit during the ninth bit time, if an address match occurs or if data was received properly. the status of ack is written into the ackdt bit on the falling edge of the ninth clock. if the master receives an acknowledge, the acknowledge status bit, ackstat, is cleared. if not, the bit is set. after the ninth clock, the sspif bit is set and the master clock (baud rate generator) is suspended until the next data byte is loaded into the sspbuf, leav- ing scl low and sda unchanged (figure 14-18). after the write to the sspbuf, each bit of address will be shifted out on the falling edge of scl until all seven address bits and the r/w bit are completed. on the fall- ing edge of the eighth clock, the master will de-assert the sda pin allowing the slave to respond with an acknowledge. on the falling edge of the ninth clock, the master will sample the sda pin to see if the address was recognized by a slave. the status of the ack bit is loaded into the ackstat status bit (sspcon2<6>). following the falling edge of the ninth clock transmis- sion of the address, the sspif is set, the bf flag is cleared and the baud rate generator is turned off until another write to the sspbuf takes place, holding scl low and allowing sda to float. 14.3.8.1 bf status flag in transmit mode, the bf bit (sspstat<0>) is set when the cpu writes to sspbuf and is cleared when all 8 bits are shifted out. 14.3.8.2 wcol status flag if the user writes the sspbuf when a transmit is already in progress, (i.e. sspsr is still shifting out a data byte), the wcol is set and the contents of the buffer are unchanged (the write doesnt occur). wcol must be cleared in software. 14.3.8.3 ackstat status flag in transmit mode, the ackstat bit (sspcon2<6>) is cleared when the slave has sent an acknowledge (ack = 0), and is set when the slave does not acknowl- edge (ack = 1). a slave sends an acknowledge when it has recognized its address (including a general call) or when the slave has properly received its data. 14.3.9 i 2 c master mode reception master mode reception is enabled by programming the receive enable bit, rcen (sspcon2<3>). the baud rate generator begins counting, and on each rollover, the state of the scl pin changes (high to low/ low to high) and data is shifted into the sspsr. after the falling edge of the eighth clock, the receive enable flag is automatically cleared, the contents of the sspsr are loaded into the sspbuf, the bf flag bit is set, the sspif flag bit is set and the baud rate genera- tor is suspended from counting, holding scl low. the mssp is now in idle state, awaiting the next com- mand. when the buffer is read by the cpu, the bf flag bit is automatically cleared. the user can then send an acknowledge bit at the end of reception, by setting the acknowledge sequence enable bit acken (sspcon2<4>). 14.3.9.1 bf status flag in receive operation, the bf bit is set when an address or data byte is loaded into sspbuf from sspsr. it is cleared when the sspbuf register is read. 14.3.9.2 sspov status flag in receive operation, the sspov bit is set when 8 bits are received into the sspsr and the bf flag bit is already set from a previous reception. 14.3.9.3 wcol status flag if the user writes the sspbuf when a receive is already in progress (i.e. sspsr is still shifting in a data byte), the the wcol bit is set and the contents of the buffer are unchanged (the write doesnt occur). note: the mssp module must be in an idle state before the rcen bit is set, or the rcen bit will be disregarded.
pic18cxx2 ds39026b-page 140 preliminary ? 7/99 microchip technology inc. figure 14-18: i 2 c master mode waveform (transmission, 7 or 10-bit address) sda scl sspif bf (sspstat<0>) sen a7 a6 a5 a4 a3 a2 a1 ack = 0 d7d6d5d4d3d2d1d0 ack transmitting data or second half r/w = 0 transmit address to slave 123456789 123456789 p cleared in software service routine sspbuf is written in software from ssp interrupt after start condition sen cleared by hardware. s sspbuf written with 7 bit address and r/w start transmit scl held low while cpu responds to sspif sen = 0 of 10-bit address write sspcon2<0> sen = 1 start condition begins from slave clear ackstat bit sspcon2<6> ackstat in sspcon2 = 1 cleared in software sspbuf written pen cleared in software r/w
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 141 figure 14-19: i 2 c master mode waveform (reception, 7-bit address) p 9 8 7 6 5 d0 d1 d2 d3 d4 d5 d6 d7 s a7 a6 a5 a4 a3 a2 a1 sda scl 12 3 4 5 6 7 8 9 12 3 4 5 678 9 1234 bus master terminates transfer ack receiving data from slave receiving data from slave d0 d1 d2 d3 d4 d5 d6 d7 ack r/w = 1 transmit address to slave sspif bf ack is not sent write to sspcon2<0> (sen = 1) write to sspbuf occurs here ack from slave master configured as a receiver by programming sspcon2<3>, (rcen = 1) pen bit = 1 written here data shifted in on falling edge of clk cleared in software start xmit sen = 0 sspov sda = 0, scl = 1 while cpu (sspstat<0>) ack last bit is shifted into sspsr and contents are unloaded into sspbuf cleared in software cleared in software set sspif interrupt at end of receive set p bit (sspstat<4>) and sspif cleared in software ack from master set sspif at end set sspif interrupt at end of acknowledge sequence set sspif interrupt at end of acknow- ledge sequence of receive set acken start acknowledge sequence sspov is set because sspbuf is still full sda = ackdt = 1 rcen cleared automatically rcen = 1 start next receive write to sspcon2<4> to start acknowledge sequence sda = ackdt (sspcon2<5>) = 0 rcen cleared automatically responds to sspif acken begin start condition cleared in software sda = ackdt = 0
pic18cxx2 ds39026b-page 142 preliminary ? 7/99 microchip technology inc. 14.3.10 acknowledge sequence timing an acknowledge sequence is enabled by setting the acknowledge sequence enable bit acken (sspcon2<4>). when this bit is set, the scl pin is pulled low and the contents of the acknowledge data bit is presented on the sda pin. if the user wishes to gen- erate an acknowledge, then the ackdt bit should be cleared. if not, the user should set the ackdt bit before starting an acknowledge sequence. the baud rate generator then counts for one rollover period (t brg ) and the scl pin is de-asserted (pulled high). when the scl pin is sampled high (clock arbitration), the baud rate generator counts for t brg . the scl pin is then pulled low. following this, the acken bit is auto- matically cleared, the baud rate generator is turned off and the mssp module then goes into idle mode (figure 14-20). 14.3.10.1 wcol status flag if the user writes the sspbuf when an acknowledge sequence is in progress, then wcol is set and the contents of the buffer are unchanged (the write doesnt occur). 14.3.11 stop condition timing a stop bit is asserted on the sda pin at the end of a receive/transmit by setting the stop sequence enable bit, pen (sspcon2<2>). at the end of a receive/trans- mit the scl line is held low after the falling edge of the ninth clock. when the pen bit is set, the master will assert the sda line low. when the sda line is sampled low, the baud rate generator is reloaded and counts down to 0. when the baud rate generator times out, the scl pin will be brought high, and one t brg (baud rate generator rollover count) later, the sda pin will be de- asserted. when the sda pin is sampled high while scl is high, the p bit (sspstat<4>) is set. a t brg later, the pen bit is cleared and the sspif bit is set (figure 14- 21). 14.3.11.1 wcol status flag if the user writes the sspbuf when a stop sequence is in progress, then the wcol bit is set and the con- tents of the buffer are unchanged (the write doesnt occur). figure 14-20: acknowledge sequence waveform note: t brg = one baud rate generator period. sda scl set sspif at the end acknowledge sequence starts here, write to sspcon2 acken automatically cleared cleared in t brg t brg of receive ack 8 acken = 1, ackdt = 0 d0 9 sspif software set sspif at the end of acknowledge sequence cleared in software
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 143 figure 14-21: stop condition receive or transmit mode scl sda sda asserted low before rising edge of clock write to sspcon2 set pen falling edge of scl = 1 for tbrg, followed by sda = 1 for tbrg 9th clock scl brought high after t brg note: t brg = one baud rate generator period. t brg t brg after sda sampled high. p bit (sspstat<4>) is set t brg to setup stop condition . ack p t brg pen bit (sspcon2<2>) is cleared by hardware and the sspif bit is set
pic18cxx2 ds39026b-page 144 preliminary ? 7/99 microchip technology inc. 14.3.12 clock arbitration clock arbitration occurs when the master, during any receive, transmit or repeated start/stop condition, de- asserts the scl pin (scl allowed to float high). when the scl pin is allowed to float high, the baud rate gen- erator (brg) is suspended from counting until the scl pin is actually sampled high. when the scl pin is sam- pled high, the baud rate generator is reloaded with the contents of sspadd<6:0> and begins counting. this ensures that the scl high time will always be at least one brg rollover count in the event that the clock is held low by an external device (figure 14-22). 14.3.13 sleep operation while in sleep mode, the i 2 c module can receive addresses or data, and when an address match or complete byte transfer occurs, wake the processor from sleep (if the mssp interrupt is enabled). 14.3.14 effect of a reset a reset disables the mssp module and terminates the current transfer. figure 14-22: clock arbitration timing in master transmit mode scl sda brg overflow, release scl, if scl = 1 load brg with sspadd<6:0>, and start count brg overflow occurs, release scl, slave device holds scl low. scl = 1 brg starts counting clock high interval. scl line sampled once every machine cycle (t osc 2 4). hold off brg until scl is sampled high. t brg t brg t brg to measure high time interval
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 145 14.3.15 multi-master mode in multi-master mode, the interrupt generation on the detection of the start and stop conditions allows the determination of when the bus is free. the stop (p) and start (s) bits are cleared from a reset or when the mssp module is disabled. control of the i 2 c bus may be taken when the p bit (sspstat<4>) is set, or the bus is idle with both the s and p bits clear. when the bus is busy, enabling the ssp interrupt will gener- ate the interrupt when the stop condition occurs. in multi-master operation, the sda line must be moni- tored, for arbitration, to see if the signal level is the expected output level. this check is performed in hard- ware, with the result placed in the bclif bit. the states where arbitration can be lost are: ? address transfer ? data transfer ? a start condition ? a repeated start condition ? an acknowledge condition 14.3.16 multi -master communication, bus collision, and bus arbitration multi-master mode support is achieved by bus arbitra- tion. when the master outputs address/data bits onto the sda pin, arbitration takes place when the master outputs a '1' on sda by letting sda float high and another master asserts a '0'. when the scl pin floats high, data should be stable. if the expected data on sda is a '1' and the data sampled on the sda pin = '0', then a bus collision has taken place. the master will set the bus collision interrupt flag bclif and reset the i 2 c port to its idle state. (figure 14-23). if a transmit was in progress when the bus collision occurred, the transmission is halted, the bf flag is cleared, the sda and scl lines are de-asserted, and the sspbuf can be written to. when the user services the bus collision interrupt service routine, and if the i 2 c bus is free, the user can resume communication by asserting a start condition. if a start, repeated start, stop, or acknowledge condition was in progress when the bus collision occurred, the condition is aborted, the sda and scl lines are de-asserted, and the respective control bits in the sspcon2 register are cleared. when the user ser- vices the bus collision interrupt service routine, and if the i 2 c bus is free, the user can resume communication by asserting a start condition. the master will continue to monitor the sda and scl pins. if a stop condition occurs, the sspif bit will be set. a write to the sspbuf will start the transmission of data at the first data bit, regardless of where the trans- mitter left off when the bus collision occurred. in multi-master mode, the interrupt generation on the detection of start and stop conditions allows the deter- mination of when the bus is free. control of the i 2 c bus can be taken when the p bit is set in the sspstat reg- ister, or the bus is idle and the s and p bits are cleared. figure 14-23: bus collision timing for transmit and acknowledge sda scl bclif sda released sda line pulled low by another source sample sda. while scl is high data doesnt match what is driven bus collision has occurred. set bus collision interrupt (bclif). by the master. by master data changes while scl = 0
pic18cxx2 ds39026b-page 146 preliminary ? 7/99 microchip technology inc. 14.3.16.1 bus collision during a start condition during a start condition, a bus collision occurs if: a) sda or scl are sampled low at the beginning of the start condition (figure 14-24). b) scl is sampled low before sda is asserted low (figure 14-25). during a start condition, both the sda and the scl pins are monitored. if: the sda pin is already low or the scl pin is already low, then: the start condition is aborted, and the bclif flag is set, and the mssp module is reset to its idle state (figure 14-24). the start condition begins with the sda and scl pins de-asserted. when the sda pin is sampled high, the baud rate generator is loaded from sspadd<6:0> and counts down to 0. if the scl pin is sampled low while sda is high, a bus collision occurs, because it is assumed that another master is attempting to drive a data '1' during the start condition. if the sda pin is sampled low during this count, the brg is reset and the sda line is asserted early (figure 14-26). if however a '1' is sampled on the sda pin, the sda pin is asserted low at the end of the brg count. the baud rate generator is then reloaded and counts down to 0, and during this time, if the scl pins is sampled as '0', a bus collision does not occur. at the end of the brg count, the scl pin is asserted low. figure 14-24: bus collision during start condition (sda only) note: the reason that bus collision is not a factor during a start condition is that no two bus masters can assert a start condition at the exact same time. therefore, one master will always assert sda before the other. this condition does not cause a bus collision, because the two masters must be allowed to arbitrate the first address follow- ing the start condition. if the address is the same, arbitration must be allowed to continue into the data portion, repeated start or stop conditions. sda scl sen sda sampled low before sda goes low before the sen bit is set. s bit and sspif set because ssp module reset into idle state. sen cleared automatically because of bus collision. s bit and sspif set because set sen, enable start condition if sda = 1, scl=1 sda = 0, scl = 1 bclif s sspif sda = 0, scl = 1 sspif and bclif are cleared in software. sspif and bclif are cleared in software. . set bclif, set bclif. start condition.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 147 figure 14-25: bus collision during start condition (scl = 0) figure 14-26: brg reset due to sda arbitration during start condition sda scl sen bus collision occurs, set bclif. scl = 0 before sda = 0, set sen, enable start sequence if sda = 1, scl = 1 t brg t brg sda = 0, scl = 1 bclif s sspif interrupt cleared in software. bus collision occurs, set bclif. scl = 0 before brg time out, '0' '0' '0' '0' sda scl sen set s set sen, enable start sequence if sda = 1, scl = 1 less than t brg t brg sda = 0, scl = 1 bclif s sspif s interrupts cleared in software. set sspif sda = 0, scl = 1 sda pulled low by other master. reset brg and assert sda scl pulled low after brg timeout set sspif '0'
pic18cxx2 ds39026b-page 148 preliminary ? 7/99 microchip technology inc. 14.3.16.2 bus collision during a repeated start condition during a repeated start condition, a bus collision occurs if: a) a low level is sampled on sda when scl goes from low level to high level. b) scl goes low before sda is asserted low, indi- cating that another master is attempting to trans- mit a data 1. when the user de-asserts sda and the pin is allowed to float high, the brg is loaded with sspadd<6:0> and counts down to 0. the scl pin is then de-asserted, and when sampled high, the sda pin is sampled. if sda is low, a bus collision has occurred (i.e. another master, figure 14-27, is attempting to transmit a data 0). if sda is sampled high, the brg is reloaded and begins counting. if sda goes from high to low before the brg times out, no bus collision occurs because no two masters can assert sda at exactly the same time. if scl goes from high to low before the brg times out and sda has not already been asserted, a bus collision occurs. in this case, another master is attempting to transmit a data 1 during the repeated start condition, figure 14-28. if at the end of the brg time out both scl and sda are still high, the sda pin is driven low and the brg is reloaded and begins counting. at the end of the count, regardless of the status of the scl pin, the scl pin is driven low and the repeated start condition is com- plete. figure 14-27: bus collision during a repeated start condition (case 1) figure 14-28: bus collision during repeated start condition (case 2) sda scl rsen bclif s sspif sample sda when scl goes high. if sda = 0, set bclif and release sda and scl cleared in software '0' '0' sda scl bclif rsen s sspif interrupt cleared in software scl goes low before sda, set bclif. release sda and scl t brg t brg '0'
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 149 14.3.16.3 bus collision during a stop condition bus collision occurs during a stop condition if: a) after the sda pin has been de-asserted and allowed to float high, sda is sampled low after the brg has timed out. b) after the scl pin is de-asserted, scl is sam- pled low before sda goes high. the stop condition begins with sda asserted low. when sda is sampled low, the scl pin is allowed to float. when the pin is sampled high (clock arbitration), the baud rate generator is loaded with sspadd<6:0> and counts down to 0. after the brg times out sda is sampled. if sda is sampled low, a bus collision has occurred. this is due to another master attempting to drive a data '0' (figure 14-29). if the scl pin is sampled low before sda is allowed to float high, a bus collision occurs. this is another case of another master attempt- ing to drive a data '0' (figure 14-30). figure 14-29: bus collision during a stop condition (case 1) figure 14-30: bus collision during a stop condition (case 2) sda scl bclif pen p sspif t brg t brg t brg sda asserted low sda sampled low after t brg , set bclif '0' '0' sda scl bclif pen p sspif t brg t brg t brg assert sda scl goes low before sda goes high set bclif '0' '0'
pic18cxx2 ds39026b-page 150 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 151 15.0 addressable universal synchronous asynchronous receiver transmitter (usart) the universal synchronous asynchronous receiver transmitter (usart) module is one of the two serial i/o modules. (usart is also known as a serial com- munications interface or sci). the usart can be con- figured as a full duplex asynchronous system that can communicate with peripheral devices, such as crt ter- minals and personal computers, or it can be configured as a half duplex synchronous system that can commu- nicate with peripheral devices, such as a/d or d/a inte- grated circuits, serial eeproms, etc. the usart can be configured in the following modes: ? asynchronous (full duplex) ? synchronous - master (half duplex) ? synchronous - slave (half duplex) bit spen (rcsta<7>) and bits trisc<7:6> have to be set in order to configure pins rc6/tx/ck and rc7/rx/dt as the universal synchronous asynchro- nous receiver transmitter. register 15-1: txsta: transmit status and control register r/w-0 r/w-0 r/w-0 r/w-0 u-0 r/w-0 r-1 r/w-0 csrc tx9 txen sync brgh trmt tx9d bit 7 bit 0 bit 7 csrc: clock source select bit asynchronous mode dont care synchronous mode 1 = master mode (clock generated internally from brg) 0 = slave mode (clock from external source) bit 6 tx9 : 9-bit transmit enable bit 1 = selects 9-bit transmission 0 = selects 8-bit transmission bit 5 txen : transmit enable bit 1 = transmit enabled 0 = transmit disabled note: sren/cren overrides txen in sync mode. bit 4 sync : usart mode select bit 1 = synchronous mode 0 = asynchronous mode bit 3 unimplemented: read as '0' bit 2 brgh : high baud rate select bit asynchronous mode 1 = high speed 0 = low speed synchronous mode unused in this mode bit 1 trmt : transmit shift register status bit 1 = tsr empty 0 = tsr full bit 0 tx9d: 9th bit of transmit data. can be address/data bit or a parity bit. legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 152 preliminary ? 7/99 microchip technology inc. register 15-2: rcsta: receive status and control register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r-0 r-0 r-x spen rx9 sren cren adden ferr oerr rx9d bit 7 bit 0 bit 7 spen: serial port enable bit 1 = serial port enabled (configures rx/dt and tx/ck pins as serial port pins) 0 = serial port disabled bit 6 rx9 : 9-bit receive enable bit 1 = selects 9-bit reception 0 = selects 8-bit reception bit 5 sren : single receive enable bit asynchronous mode dont care synchronous mode - master 1 = enables single receive 0 = disables single receive this bit is cleared after reception is complete. synchronous mode - slave unused in this mode bit 4 cren : continuous receive enable bit asynchronous mode 1 = enables continuous receive 0 = disables continuous receive synchronous mode 1 = enables continuous receive until enable bit cren is cleared (cren overrides sren) 0 = disables continuous receive bit 3 adden : address detect enable bit asynchronous mode 9-bit (rx9 = 1) 1 = enables address detection, enable interrupt and load of the receive buffer when rsr<8> is set 0 = disables address detection, all bytes are received, and ninth bit can be used as parity bit bit 2 ferr : framing error bit 1 = framing error (can be updated by reading rcreg register and receive next valid byte) 0 = no framing error bit 1 oerr : overrun error bit 1 = overrun error (can be cleared by clearing bit cren) 0 = no overrun error bit 0 rx9d: 9th bit of received data, can be address/data bit or a parity bit. legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 153 15.1 usart baud rate generator (brg) the brg supports both the asynchronous and syn- chronous modes of the usart. it is a dedicated 8-bit baud rate generator. the spbrg register controls the period of a free running 8-bit timer. in asynchronous mode, bit brgh (txsta<2>) also controls the baud rate. in synchronous mode, bit brgh is ignored. table 15-1 shows the formula for computation of the baud rate for different usart modes, which only apply in master mode (internal clock). given the desired baud rate and fosc, the nearest inte- ger value for the spbrg register can be calculated using the formula in table 15-1. from this, the error in baud rate can be determined. example 15-1 shows the calculation of the baud rate error for the following conditions: f osc = 16 mhz desired baud rate = 9600 brgh = 0 sync = 0 it may be advantageous to use the high baud rate (brgh = 1) even for slower baud clocks. this is because the f osc /(16(x + 1)) equation can reduce the baud rate error in some cases. writing a new value to the spbrg register causes the brg timer to be reset (or cleared). this ensures the brg does not wait for a timer overflow before output- ting the new baud rate. 15.1.1 sampling the data on the rc7/rx/dt pin is sampled three times by a majority detect circuit to determine if a high or a low level is present at the rx pin. example 15-1: calculating baud rate error table 15-1: baud rate formula table 15-2: registers associated with baud rate generator sync brgh = 0 (low speed) brgh = 1 (high speed) 0 1 (asynchronous) baud rate = f osc /(64(x+1)) (synchronous) baud rate = f osc /(4(x+1)) baud rate= f osc /(16(x+1)) na x = value in spbrg (0 to 255) name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, - = unimplemented read as '0'. shaded cells are not used by the brg. desired baud rate = fosc / (64 (x + 1)) solving for x: x = ( (fosc / desired baud rate) / 64 ) - 1 x = ((16000000 / 9600) / 64) - 1 x = [25.042] = 25 calculated baud rate = 16000000 / (64 (25 + 1)) = 9615 error = (calculated baud rate - desired baud rate) desired baud rate = (9615 - 9600) / 9600 = 0.16%
pic18cxx2 ds39026b-page 154 preliminary ? 7/99 microchip technology inc. table 15-3: baud rates for synchronous mode baud rate (k) f osc = 20 mhz spbrg value (decimal) 16 mhz spbrg value (decimal) 10 mhz spbrg value (decimal) 7.15909 mhz spbrg value (decimal) %% %% 0.3na- - na- - na- - na- - 1.2na- - na- - na- - na- - 2.4na- - na- - na- - na- - 9.6 na - - na - - 9.766 +1.73 255 9.622 +0.23 185 19.2 19.53 +1.73 255 19.23 +0.16 207 19.23 +0.16 129 19.24 +0.23 92 76.8 76.92 +0.16 64 76.92 +0.16 51 75.76 -1.36 32 77.82 +1.32 22 96 96.15 +0.16 51 95.24 -0.79 41 96.15 +0.16 25 94.20 -1.88 18 300 294.1 -1.96 16 307.69 +2.56 12 312.5 +4.17 7 298.3 -0.57 5 500 500 0 9 500 0 7 500 0 4 na - - high 5000 - 0 4000 - 0 2500 - 0 1789.8 - 0 low 19.53 - 255 15.625 - 255 9.766 - 255 6.991 - 255 baud rate (k) f osc = 5.0688 mhz 4 mhz spbrg value (decimal) 3.579545 mhz spbrg value (decimal) 1 mhz spbrg value (decimal) 32.768 khz spbrg value (decimal) % spbrg % % % % 0.3 na - - na - - na - - na - - 0.303 +1.14 26 1.2 na - - na - - na - - 1.202 +0.16 207 1.170 -2.48 6 2.4 na - - na - - na - - 2.404 +0.16 103 na - - 9.6 9.6 0 131 9.615 +0.16 103 9.622 +0.23 92 9.615 +0.16 25 na - - 19.2 19.2 0 65 19.231 +0.16 51 19.04 -0.83 46 19.24 +0.16 12 na - - 76.8 79.2 +3.13 15 76.923 +0.16 12 74.57 -2.90 11 83.34 +8.51 2 na - - 96 97.48 +1.54 12 1000 +4.17 9 99.43 +3.57 8 na - - na - - 300 316.8 +5.60 3 na - - 298.3 -0.57 2 na - - na - - 500 na - - na - - na - - na - - na - - high 1267 - 0 100 - 0 894.9 - 0 250 - 0 8.192 - 0 low 4.950 - 255 3.906 - 255 3.496 - 255 0.9766 - 255 0.032 - 255
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 155 table 15-4: baud rates for asynchronous mode (brgh = 0) baud rate (k) f osc = 20 mhz spbrg value (decimal) 16 mhz spbrg value (decimal) 10 mhz spbrg value (decimal) 7.15909 mhz spbrg value (decimal) %% %% 0.3 na - - na - - na - - na - - 1.2 1.221 +1.73 255 1.202 +0.16 207 1.202 +0.16 129 1.203 +0.23 92 2.4 2.404 +0.16 129 2.404 +0.16 103 2.404 +0.16 64 2.380 -0.83 46 9.6 9.469 -1.36 32 9.615 +0.16 25 9.766 +1.73 15 9.322 -2.90 11 19.2 19.53 +1.73 15 19.23 +0.16 12 19.53 +1.73 7 18.64 -2.90 5 76.8 78.13 +1.73 3 83.33 +8.51 2 78.13 +1.73 1 na - - 96 104.2 +8.51 2 na - - na - - na - - 300 312.5 +4.17 0 na - - na - - na - - 500 na - - na - - na - - na - - high 312.5 - 0 250 - 0 156.3 - 0 111.9 - 0 low 1.221 - 255 0.977 - 255 0.6104 - 255 0.437 - 255 baud rate (k) f osc = 5.0688 mhz 4 mhz spbrg value (decimal) 3.579545 mhz spbrg value (decimal) 1 mhz spbrg value (decimal) 32.768 khz spbrg value (decimal) % spbrg % % % % 0.3 0.31 +3.13 255 0.3005 -0.17 207 0.301 +0.23 185 0.300 +0.16 51 0.256 -14.67 1 1.2 1.2 0 65 1.202 +1.67 51 1.190 -0.83 46 1.202 +0.16 12 na - - 2.4 2.4 0 32 2.404 +1.67 25 2.432 +1.32 22 2.232 -6.99 6 na - - 9.6 9.9 +3.13 7 na - - 9.322 -2.90 5 na - - na - - 19.2 19.8 +3.13 3 na - - 18.64 -2.90 2 na - - na - - 76.8 79.2 +3.13 0 na - - na - - na - - na - - 96 na - - na - - na - - na - - na - - 300 na - - na - - na - - na - - na - - 500 na - - na - - na - - na - - na - - high 79.2 - 0 62.500 - 0 55.93 - 0 15.63 - 0 0.512 - 0 low 0.3094 - 255 3.906 - 255 0.2185 - 255 0.0610 - 255 0.0020 - 255
pic18cxx2 ds39026b-page 156 preliminary ? 7/99 microchip technology inc. table 15-5: baud rates for asynchronous mode (brgh = 1) baud rate (k) f osc = 20 mhz spbrg value (decimal) 16 mhz spbrg value (decimal) 10 mhz spbrg value (decimal) 7.16 mhz spbrg value (decimal) %%%% 9.6 9.615 +0.16 129 9.615 +0.16 103 9.615 +0.16 64 9.520 -0.83 46 19.2 19.230 +0.16 64 19.230 +0.16 51 18.939 -1.36 32 19.454 +1.32 22 38.4 37.878 -1.36 32 38.461 +0.16 25 39.062 +1.7 15 37.286 -2.90 11 57.6 56.818 -1.36 21 58.823 +2.12 16 56.818 -1.36 10 55.930 -2.90 7 115.2 113.636 -1.36 10 111.111 -3.55 8 125 +8.51 4 111.860 -2.90 3 250 250 0 4 250 0 3 na - - na - - 625 625 0 1 na - - 625 0 0 na - - 1250 1250 0 0 na - - na - - na - - baud rate (k) f osc = 5.068 spbrg value (decimal) 4 mhz spbrg value (decimal) 3.579 mhz spbrg value (decimal) 1 mhz spbrg value (decimal) 32.768 khz spbrg value (decimal) %%%%% 9.6 9.6 0 32 na - - 9.727 +1.32 22 8.928 -6.99 6 na - - 19.2 18.645 -2.94 16 1.202 +0.17 207 18.643 -2.90 11 20.833 +8.51 2 na - - 38.4 39.6 +3.12 7 2.403 +0.13 103 37.286 -2.90 5 31.25 -18.61 1 na - - 57.6 52.8 -8.33 5 9.615 +0.16 25 55.930 -2.90 3 62.5 +8.51 0 na - - 115.2 105.6 -8.33 2 19.231 +0.16 12 111.86 -2.90 1 na - - na - - 250 na - - na - - 223.72 -10.51 0 na - - na - - 625 na - - na - - na - - na - - na - - 1250 na - - na - - na - - na - - na - -
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 157 15.2 usart asynchronous mode in this mode, the usart uses standard non-return-to- zero (nrz) format (one start bit, eight or nine data bits and one stop bit). the most common data format is 8-bits. an on-chip dedicated 8-bit baud rate generator can be used to derive standard baud rate frequencies from the oscillator. the usart transmits and receives the lsb first. the usarts transmitter and receiver are functionally independent, but use the same data format and baud rate. the baud rate generator produces a clock, either x16 or x64 of the bit shift rate, depending on bit brgh (txsta<2>). parity is not supported by the hardware, but can be implemented in software (and stored as the ninth data bit). asynchronous mode is stopped during sleep. asynchronous mode is selected by clearing bit sync (txsta<4>). the usart asynchronous module consists of the fol- lowing important elements: ? baud rate generator ? sampling circuit ? asynchronous transmitter ? asynchronous receiver 15.2.1 usart asynchronous transmitter the usart transmitter block diagram is shown in figure 15-1. the heart of the transmitter is the transmit (serial) shift register (tsr). the shift register obtains its data from the read/write transmit buffer, txreg. the txreg register is loaded with data in software. the tsr register is not loaded until the stop bit has been transmitted from the previous load. as soon as the stop bit is transmitted, the tsr is loaded with new data from the txreg register (if available). once the txreg register transfers the data to the tsr register (occurs in one t cy ), the txreg register is empty and flag bit txif (pir1<4>) is set. this interrupt can be enabled/disabled by setting/clearing enable bit txie ( pie1<4>). flag bit txif will be set regardless of the state of enable bit txie and cannot be cleared in soft- ware. it will reset only when new data is loaded into the txreg register. while flag bit txif indicated the sta- tus of the txreg register, another bit trmt (txsta<1>) shows the status of the tsr register. sta- tus bit trmt is a read only bit, which is set when the tsr register is empty. no interrupt logic is tied to this bit, so the user has to poll this bit in order to determine if the tsr register is empty. steps to follow when setting up an asynchronous trans- mission: 1. initialize the spbrg register for the appropriate baud rate. if a high speed baud rate is desired, set bit brgh. (section 15.1) 2. enable the asynchronous serial port by clearing bit sync and setting bit spen. 3. if interrupts are desired, set enable bit txie. 4. if 9-bit transmission is desired, set transmit bit tx9. can be used as address/data bit. 5. enable the transmission by setting bit txen, which will also set bit txif. 6. if 9-bit transmission is selected, the ninth bit should be loaded in bit tx9d. 7. load data to the txreg register (starts trans- mission). figure 15-1: usart transmit block diagram note 1: the tsr register is not mapped in data memory, so it is not available to the user. note 2: flag bit txif is set when enable bit txen is set. txif txie interrupt txen baud rate clk spbrg baud rate generator tx9d msb lsb data bus txreg register tsr register (8) 0 tx9 trmt spen rc6/tx/ck pin pin buffer and control 8
pic18cxx2 ds39026b-page 158 preliminary ? 7/99 microchip technology inc. figure 15-2: asynchronous transmission figure 15-3: asynchronous transmission (back to back) table 15-6: registers associated with asynchronous transmission name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x txreg usart transmit register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, - = unimplemented locations read as '0'. shaded cells are not used for asynchronous transmission. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear. word 1 stop bit word 1 transmit shift reg start bit bit 0 bit 1 bit 7/8 write to txreg word 1 brg output (shift clock) rc6/tx/ck (pin) txif bit (transmit buffer reg. empty flag) trmt bit (transmit shift reg. empty flag) transmit shift reg. write to txreg brg output (shift clock) rc6/tx/ck (pin) txif bit (interrupt reg. flag) trmt bit (transmit shift reg. empty flag) word 1 word 2 word 1 word 2 start bit stop bit start bit transmit shift reg. word 1 word 2 bit 0 bit 1 bit 7/8 bit 0 note: this timing diagram shows two consecutive transmissions.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 159 15.2.2 usart asynchronous receiver the receiver block diagram is shown in figure 15-4. the data is received on the rc7/rx/dt pin and drives the data recovery block. the data recovery block is actually a high speed shifter operating at x16 times the baud rate, whereas the main receive serial shifter oper- ates at the bit rate or at f osc . this mode would typi- cally be used in rs-232 systems. steps to follow when setting up an asynchronous reception: 1. initialize the spbrg register for the appropriate baud rate. if a high speed baud rate is desired, set bit brgh. (section 15.1). 2. enable the asynchronous serial port by clearing bit sync and setting bit spen. 3. if interrupts are desired, set enable bit rcie. 4. if 9-bit reception is desired, set bit rx9. 5. enable the reception by setting bit cren. 6. flag bit rcif will be set when reception is com- plete and an interrupt will be generated if enable bit rcie was set. 7. read the rcsta register to get the ninth bit (if enabled) and determine if any error occurred during reception. 8. read the 8-bit received data by reading the rcreg register. 9. if any error occurred, clear the error by clearing enable bit cren. 15.2.3 setting up 9-bit mode with address detect this mode would typically be used in rs-485 systems. steps to follow when setting up an asynchronous reception with address detect enable: 1. initialize the spbrg register for the appropriate baud rate. if a high speed baud rate is required, set the brgh bit. 2. enable the asynchronous serial port by clearing the sync bit and setting the spen bit. 3. if interrupts are required, set the rcen bit and select the desired priority level with the rcip bit. 4. set the rx9 bit to enable 9-bit reception. 5. set the adden bit to enable address detect. 6. enable reception by setting the cren bit. 7. the rcif bit will be set when reception is com- plete. the interrupt will be acknowledged if the rcie and gie bits are set. 8. read the rcsta register to determine if any error occurred during reception, as well as read bit 9 of data (if applicable). 9. read rcreg to determine if the device is being addressed. 10. if any error occurred, clear the cren bit. 11. if the device has been addressed, clear the adden bit to allow all received data into the receive buffer and interrupt the cpu. figure 15-4: usart receive block diagram x64 baud rate clk spbrg baud rate generator rc7/rx/dt pin buffer and control spen data recovery cren oerr ferr rsr register msb lsb rx9d rcreg register fifo interrupt rcif rcie data bus 8 ? 64 ? 16 or stop start (8) 7 1 0 rx9
pic18cxx2 ds39026b-page 160 preliminary ? 7/99 microchip technology inc. figure 15-5: asynchronous reception table 15-7: registers associated with asynchronous reception name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x rcreg usart receive register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, - = unimplemented locations read as '0'. shaded cells are not used for asynchronous reception. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear. start bit bit7/8 bit1 bit0 bit7/8 bit0 stop bit start bit start bit bit7/8 stop bit rx (pin) reg rcv buffer reg rcv shift read rcv buffer reg rcreg rcif (interrupt flag) oerr bit cren word 1 rcreg word 2 rcreg stop bit note: this timing diagram shows three words appearing on the rx input. the rcreg (receive buffer) is read after the third word, causing the oerr (overrun) bit to be set.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 161 15.3 usart synchronous master mode in synchronous master mode, the data is transmitted in a half-duplex manner, (i.e. transmission and reception do not occur at the same time). when transmitting data, the reception is inhibited and vice versa. synchronous mode is entered by setting bit sync (txsta<4>). in addition, enable bit spen (rcsta<7>) is set in order to configure the rc6/tx/ck and rc7/rx/dt i/o pins to ck (clock) and dt (data) lines respectively. the master mode indicates that the processor transmits the master clock on the ck line. the master mode is entered by setting bit csrc (txsta<7>). 15.3.1 usart synchronous master transmission the usart transmitter block diagram is shown in figure 15-1. the heart of the transmitter is the transmit (serial) shift register (tsr). the shift register obtains its data from the read/write transmit buffer register txreg. the txreg register is loaded with data in software. the tsr register is not loaded until the last bit has been transmitted from the previous load. as soon as the last bit is transmitted, the tsr is loaded with new data from the txreg (if available). once the txreg register transfers the data to the tsr register (occurs in one tcycle), the txreg is empty and inter- rupt bit txif (pir1<4>) is set. the interrupt can be enabled/disabled by setting/clearing enable bit txie (pie1<4>). flag bit txif will be set, regardless of the state of enable bit txie, and cannot be cleared in soft- ware. it will reset only when new data is loaded into the txreg register. while flag bit txif indicates the status of the txreg register, another bit trmt (txsta<1>) shows the status of the tsr register. trmt is a read only bit, which is set when the tsr is empty. no inter- rupt logic is tied to this bit, so the user has to poll this bit in order to determine if the tsr register is empty. the tsr is not mapped in data memory, so it is not available to the user. steps to follow when setting up a synchronous master transmission: 1. initialize the spbrg register for the appropriate baud rate (section 15.1). 2. enable the synchronous master serial port by setting bits sync, spen, and csrc. 3. if interrupts are desired, set enable bit txie. 4. if 9-bit transmission is desired, set bit tx9. 5. enable the transmission by setting bit txen. 6. if 9-bit transmission is selected, the ninth bit should be loaded in bit tx9d. 7. start transmission by loading data to the txreg register. table 15-8: registers associated with synchronous master transmission name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x txreg usart transmit register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, = unimplemented, read as '0'. shaded cells are not used for synchronous master transmission. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ds39026b-page 162 preliminary ? 7/99 microchip technology inc. figure 15-6: synchronous transmission figure 15-7: synchronous transmission (through txen) bit 0 bit 1 bit 7 word 1 q1 q2 q3q4 q1 q2 q3 q4 q1 q2q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q3q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 bit 2 bit 0 bit 1 bit 7 rc7/rx/dt pin rc6/tx/ck pin write to txreg reg txif bit (interrupt flag) trmt txen bit '1' '1' note: sync master mode; spbrg = '0'. continuous transmission of two 8-bit words word 2 trmt bit write word1 write word2 rc7/rx/dt pin rc6/tx/ck pin write to txreg reg txif bit trmt bit bit0 bit1 bit2 bit6 bit7 txen bit
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 163 15.3.2 usart synchronous master reception once synchronous mode is selected, reception is enabled by setting either enable bit sren (rcsta<5>) or enable bit cren (rcsta<4>). data is sampled on the rc7/rx/dt pin on the falling edge of the clock. if enable bit sren is set, only a single word is received. if enable bit cren is set, the reception is continuous until cren is cleared. if both bits are set, then cren takes precedence. steps to follow when setting up a synchronous master reception: 1. initialize the spbrg register for the appropriate baud rate. (section 15.1) 2. enable the synchronous master serial port by setting bits sync, spen and csrc. 3. ensure bits cren and sren are clear. 4. if interrupts are desired, set enable bit rcie. 5. if 9-bit reception is desired, set bit rx9. 6. if a single reception is required, set bit sren. for continuous reception, set bit cren. 7. interrupt flag bit rcif will be set when reception is complete and an interrupt will be generated if the enable bit rcie was set. 8. read the rcsta register to get the ninth bit (if enabled) and determine if any error occurred during reception. 9. read the 8-bit received data by reading the rcreg register. 10. if any error occurred, clear the error by clearing bit cren. table 15-9: registers associated with synchronous master reception name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x rcreg usart receive register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, = unimplemented read as '0'. shaded cells are not used for synchronous master reception. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ds39026b-page 164 preliminary ? 7/99 microchip technology inc. figure 15-8: synchronous reception (master mode, sren) cren bit rc7/rx/dt pin rc6/tx/ck pin write to bit sren sren bit rcif bit (interrupt) read rxreg note: timing diagram demonstrates sync master mode with bit sren = '1' and bit brgh = '0'. q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q2 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4q1 q2 q3 q4 q1 q2 q3 q4 '0' bit0 bit1 bit2 bit3 bit4 bit5 bit6 bit7 '0' q1 q2 q3 q4
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 165 15.4 usart synchronous slave mode synchronous slave mode differs from the master mode in the fact that the shift clock is supplied externally at the rc6/tx/ck pin (instead of being supplied internally in master mode). this allows the device to transfer or receive data while in sleep mode. slave mode is entered by clearing bit csrc (txsta<7>). 15.4.1 usart synchronous slave transmit the operation of the synchronous master and slave modes are identical, except in the case of the sleep mode. if two words are written to the txreg and then the sleep instruction is executed, the following will occur: a) the first word will immediately transfer to the tsr register and transmit. b) the second word will remain in txreg register. c) flag bit txif will not be set. d) when the first word has been shifted out of tsr, the txreg register will transfer the second word to the tsr and flag bit txif will now be set. e) if enable bit txie is set, the interrupt will wake the chip from sleep. if the global interrupt is enabled, the program will branch to the interrupt vector. steps to follow when setting up a synchronous slave transmission: 1. enable the synchronous slave serial port by set- ting bits sync and spen and clearing bit csrc. 2. clear bits cren and sren. 3. if interrupts are desired, set enable bit txie. 4. if 9-bit transmission is desired, set bit tx9. 5. enable the transmission by setting enable bit txen. 6. if 9-bit transmission is selected, the ninth bit should be loaded in bit tx9d. 7. start transmission by loading data to the txreg register. 15.4.2 usart synchronous slave reception the operation of the synchronous master and slave modes is identical, except in the case of the sleep mode and bit sren, which is a "don't care" in slave mode. if receive is enabled by setting bit cren prior to the sleep instruction, then a word may be received during sleep. on completely receiving the word, the rsr register will transfer the data to the rcreg register, and if enable bit rcie bit is set, the interrupt generated will wake the chip from sleep. if the global interrupt is enabled, the program will branch to the interrupt vector. steps to follow when setting up a synchronous slave reception: 1. enable the synchronous master serial port by setting bits sync and spen and clearing bit csrc. 2. if interrupts are desired, set enable bit rcie. 3. if 9-bit reception is desired, set bit rx9. 4. to enable reception, set enable bit cren. 5. flag bit rcif will be set when reception is com- plete. an interrupt will be generated if enable bit rcie was set. 6. read the rcsta register to get the ninth bit (if enabled) and determine if any error occurred during reception. 7. read the 8-bit received data by reading the rcreg register. 8. if any error occurred, clear the error by clearing bit cren.
pic18cxx2 ds39026b-page 166 preliminary ? 7/99 microchip technology inc. table 15-10: registers associated with synchronous slave transmission table 15-11: registers associated with synchronous slave reception name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x txreg usart transmit register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, = unimplemented read as '0'. shaded cells are not used for synchronous slave transmission. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear. name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 rcsta spen rx9 sren cren ferr oerr rx9d 0000 -00x 0000 -00x rcreg usart receive register 0000 0000 0000 0000 txsta csrc tx9 txen sync brgh trmt tx9d 0000 -010 0000 -010 spbrg baud rate generator register 0000 0000 0000 0000 legend: x = unknown, = unimplemented read as '0'. shaded cells are not used for synchronous slave reception. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 167 16.0 10-bit analog-to-digital converter (a/d) module the analog-to-digital (a/d) converter module has five inputs for the pic18c2x2 devices and eight for the pic18c4x2 devices. this module has the adcon0 and adcon1 register definitions that are compatible with the mid-range a/d module. the a/d allows conversion of an analog input signal to a corresponding 10-bit digital number. the a/d module has four registers. these registers are: ? a/d result high register (adresh) ? a/d result low register (adresl) ? a/d control register 0 (adcon0) ? a/d control register 1 (adcon1) the adcon0 register, shown in register 16-1, con- trols the operation of the a/d module. the adcon1 register, shown in register 16-2, configures the func- tions of the port pins. register 16-1: adcon0 register r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 r/w-0 u-0 r/w-0 adcs1 adcs0 chs2 chs1 chs0 go/done adon bit 7 bit 0 bit 7:6 adcs1:adcs0: a/d conversion clock select bits (shown in bold) 0 00 = f osc /2 0 01 = f osc /8 0 10 = f osc /32 0 11 = f rc (clock derived from the internal a/d rc oscillator) 1 00 = f osc /4 1 01 = f osc /16 1 10 = f osc /64 1 11 = f rc (clock derived from the internal a/d rc oscillator) note: the adcs2 bit is located in the adcon1 register bit 5:3 chs2:chs0: analog channel select bits 000 = channel 0, (an0) 001 = channel 1, (an1) 010 = channel 2, (an2) 011 = channel 3, (an3) 100 = channel 4, (an4) 101 = channel 5, (an5) 110 = channel 6, (an6) 111 = channel 7, (an7) note: the pic18c2x2 devices do not implement the full 8 a/d channels, the unimple- mented selections are reserved. do not select any unimplemented channel. bit 2 go/done : a/d conversion status bit when adon = 1 1 = a/d conversion in progress (setting this bit starts the a/d conversion which is automatically cleared by hardware when the a/d conversion is complete) 0 = a/d conversion not in progress bit 1 unimplemented: read as '0' bit 0 adon: a/d on bit 1 = a/d converter module is powered up 0 = a/d converter module is shut off and consumes no operating current legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown
pic18cxx2 ds39026b-page 168 preliminary ? 7/99 microchip technology inc. register 16-2: adcon1 register r/w-0 r/w-0 u-0 u-0 r/w-0 r/w-0 r/w-0 r/w-0 adfm adcs2 pcfg3 pcfg2 pcfg1 pcfg0 bit 7 bit 0 bit 7:6 unimplemented: read as '0' bit 7 adfm: a/d result format select. 1 = right justified. 6 m ost significant bits of adresh are read as 0. 0 = left justified. 6 least significant bits of adresl are read as 0. bit 6 adcs2: a/d conversion clock select bit (shown in bold) 0 00 = f osc /2 0 01 = f osc /8 0 10 = f osc /32 0 11 = f rc (clock derived from the internal a/d rc oscillator) 1 00 = f osc /4 1 01 = f osc /16 1 10 = f osc /64 1 11 = f rc (clock derived from the internal a/d rc oscillator) note: the adcs1:adcs0 bits are located in the adcon0 register bit 5:4 unimplemented: read as '0' bit 3:0 pcfg3:pcfg0: a/d port configuration control bits legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset 1 = bit is set 0 = bit is cleared x = bit is unknown note: on any device reset, the port pins that are multiplexed with analog functions (anx) are forced to be an analog input. a = analog input d = digital i/o c/r = # of analog input channels / # of a/d voltage references pcfg an7 an6 an5 an4 an3 an2 an1 an0 v ref +v ref - c / r 0000 aaaaa a aav dd v ss 8 / 0 0001 aaaav ref +a a a an3 v ss 7 / 1 0010 dddaa a aav dd v ss 5 / 0 0011 dddav ref +a a a an3 v ss 4 / 1 0100 dddda d aav dd v ss 3 / 0 0101 ddddv ref +d a a an3 v ss 2 / 1 011x ddddd d dd 0 / 0 1000 aaaav ref +v ref -a aan3an26 / 2 1001 ddaaa a aav dd v ss 6 / 0 1010 ddaav ref +a a a an3 v ss 5 / 1 1011 ddaav ref +v ref -a aan3an24 / 2 1100 dddav ref +v ref -a aan3an23 / 2 1101 ddddv ref +v ref -a aan3an22 / 2 1110 ddddd d dav dd v ss 1 / 0 1111 ddddv ref +v ref -d aan3an21 / 2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 169 the analog reference voltage is software selectable to either the devices positive and negative supply voltage (v dd and v ss ) or the voltage level on the ra3/an3/ v ref + pin and ra2/an2/v ref -. the a/d converter has a unique feature of being able to operate while the device is in sleep mode. to operate in sleep, the a/d conversion clock must be derived from the a/ds internal rc oscillator. the output of the sample and hold is the input into the converter, which generates the result via successive approximation. a device reset forces all registers to their reset state. this forces the a/d module to be turned off and any conversion is aborted. each port pin associated with the a/d converter can be configured as an analog input (ra3 can also be a voltage reference) or as a digital i/o. the adresh and adresl registers contain the result of the a/d conversion. when the a/d conversion is complete, the result is loaded into the adresh/ adresl registers, the go/done bit (adcon0<2>) is cleared, and a/d interrupt flag bit adif is set. the block diagram of the a/d module is shown in figure 16-1. figure 16-1: a/d block diagram (input voltage) v ain v ref + reference voltage v dd pcfg0 chs2:chs0 an7 an6 an5 an4 an3 an2 an1 an0 111 110 101 100 011 010 001 000 10-bit converter v ref - v ss a/d
pic18cxx2 ds39026b-page 170 preliminary ? 7/99 microchip technology inc. the value that is in the adresh/adresl registers is not modified for a power-on reset. the adresh/ adresl registers will contain unknown data after a power-on reset. after the a/d module has been configured as desired, the selected channel must be acquired before the con- version is started. the analog input channels must have their corresponding tris bits selected as an input. to determine acquisition time, see section 16.1. after this acquisition time has elapsed, the a/d conver- sion can be started. the following steps should be fol- lowed for doing an a/d conversion: 1. configure the a/d module: ? configure analog pins, voltage reference and digital i/o (adcon1) ? select a/d input channel (adcon0) ? select a/d conversion clock (adcon0) ? turn on a/d module (adcon0) 2. configure a/d interrupt (if desired): ? clear adif bit ? set adie bit ? set gie bit 3. wait the required acquisition time. 4. start conversion: ? set go/done bit (adcon0) 5. wait for a/d conversion to complete, by either: ? polling for the go/done bit to be cleared or ? waiting for the a/d interrupt 6. read a/d result registers (adresh/adresl); clear bit adif if required. 7. for next conversion, go to step 1 or step 2 as required. the a/d conversion time per bit is defined as t ad . a minimum wait of 2t ad is required before next acquisition starts. 16.1 a /d acquisition requirements for the a/d converter to meet its specified accuracy, the charge holding capacitor (c hold ) must be allowed to fully charge to the input channel voltage level. the analog input model is shown in figure 16-2. the source impedance (r s ) and the internal sampling switch (r ss ) impedance directly affect the time required to charge the capacitor c hold . the sampling switch (r ss ) impedance varies over the device voltage (v dd ). the source impedance affects the offset voltage at the analog input (due to pin leakage current). the maximum recommended impedance for analog sources is 2.5k w . after the analog input channel is selected (changed), this acquisition must be done before the conversion can be started. figure 16-2: analog input model note: when the conversion is started, the hold- ing capacitor is disconnected from the input pin. v ain c pin rs anx 5 pf v dd v t = 0.6v v t = 0.6v i leakage r ic 1k sampling switch ss r ss c hold = 120 pf v ss 6v sampling switch 5v 4v 3v 2v 567891011 ( k w ) v dd 500 na legend: c pin v t i leakage r ic ss c hold = input capacitance = threshold voltage = leakage current at the pin due to = interconnect resistance = sampling switch = sample/hold capacitance (from dac) various junctions
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 171 to calculate the minimum acquisition time, equation 16-1 may be used. this equation assumes that 1/2 lsb error is used (1024 steps for the a/d). the 1/2 lsb error is the maximum error allowed for the a/d to meet its specified resolution. equation 16-1: a cquisition time equation 16-2: a/d minimum charging time example 16-3 shows the calculation of the minimum required acquisition time t acq . this calculation is based on the following application system assump- tions: c hold = 120 pf rs = 2.5 k w conversion error 1/2 lsb v dd = 5v ? rss = 7 k w temperature = 50 c (system max.) v hold =0v @ time = 0 example 16-3: calculating the minimum required acquisition time t acq = amplifier settling time + holding capacitor charging time + temperature coefficient =t amp + t c + t coff v hold = (v ref - (v ref /2048)) ? (1 - e (-tc/c hold (r ic + r ss + r s )) ) or tc = -(120 pf)(1 k w + r ss + r s ) ln(1/2047) t acq =t amp + t c + t coff temperature coefficient is only required for temperatures > 25 c. t acq =2 m s + tc + [(temp - 25 c)(0.05 m s/ c)] t c =-c hold (r ic + r ss + r s ) ln(1/2047) -120 pf (1 k w + 7 k w + 2.5 k w ) ln(0.0004885) -120 pf (10.5 k w ) ln(0.0004885) -1.26 m s (-7.6241) 9.61 m s t acq =2 m s + 9.61 m s + [(50 c - 25 c)(0.05 m s/ c)] 11.61 m s + 1.25 m s 12.86 m s
pic18cxx2 ds39026b-page 172 preliminary ? 7/99 microchip technology inc. 16.2 s electing the a/d conversion clock the a/d conversion time per bit is defined as t ad . the a/d conversion requires 12 t ad per 10-bit conversion. the source of the a/d conversion clock is software selectable. the seven possible options for t ad are: ?2t osc ?4t osc ?8t osc ?16t osc ?32t osc ?64t osc ? internal rc oscillator for correct a/d conversions, the a/d conversion clock (t ad ) must be selected to ensure a minimum t ad time of 1.6 m s. table 16-1 shows the resultant t ad times derived from the device operating frequencies and the a/d clock source selected. 16.3 configuring analog port pins the adcon1, trisa and trise registers control the operation of the a/d port pins. the port pins that are desired as analog inputs must have their corresponding tris bits set (input). if the tris bit is cleared (output), the digital output level (v oh or v ol ) will be converted. the a/d operation is independent of the state of the chs2:chs0 bits and the tris bits. table 16-1: t ad vs. device operating frequencies table 16-2: t ad vs. device operating frequencies (for extended, lc, devices) note 1: when reading the port register, all pins configured as analog input channels will read as cleared (a low level). pins config- ured as digital inputs will convert an ana- log input. analog levels on a digitally configured input will not affect the conver- sion accuracy. note 2: analog levels on any pin that is defined as a digital input (including the an4:an0 pins) may cause the input buffer to con- sume current that is out of the devices specification. ad clock source (t ad ) device frequency operation adcs2:adcs0 20 mhz 5 mhz 1.25 mhz 333.33 khz 2t osc 000 100 ns (2) 400 ns (2) 1.6 m s6 m s 4t osc 100 200 ns (2) 800 ns (2) 3.2 m s 12 m s 8t osc 001 400 ns (2) 1.6 m s6.4 m s 24 m s (3) 16t osc 101 800 ns (2) 3.2 m s 12.8 m s 48 m s (3) 32t osc 010 1.6 m s6.4 m s 25.6 m s (3) 96 m s (3) 64t osc 110 3.2 m s 12.8 m s 51.2 m s (3) 192 m s (3) rc 011 2 - 6 m s (1,4) 2 - 6 m s (1,4) 2 - 6 m s (1,4) 2 - 6 m s (1) legend: shaded cells are outside of recommended range. note 1: the rc source has a typical t ad time of 4 m s. 2: these values violate the minimum required t ad time. 3: for faster conversion times, the selection of another clock source is recommended. 4: for device frequencies above 1 mhz, the device must be in sleep for the entire conversion or the a/d accuracy may be out of specification. ad clock source (t ad ) device frequency operation adcs2:adcs0 4 mhz 2 mhz 1.25 mhz 333.33 khz 2t osc 000 500 ns (2) 1.0 m s (2) 1.6 m s (2) 6 m s 4t osc 100 1.0 m s (2) 2.0 m s (2) 3.2 m s (2) 12 m s 8t osc 001 2.0 m s (2) 4.0 m s6.4 m s 24 m s (3) 16t osc 101 4.0 m s (2) 8.0 m s 12.8 m s 48 m s (3) 32t osc 010 8.0 m s 16.0 m s 25.6 m s (3) 96 m s (3) 64t osc 110 16.0 m s 32.0 m s 51.2 m s (3) 192 m s (3) rc 011 3 - 9 m s (1,4) 3 - 9 m s (1,4) 3 - 9 m s (1,4) 3 - 9 m s (1,4) legend: shaded cells are outside of recommended range. note 1: the rc source has a typical t ad time of 6 m s. 2: these values violate the minimum required t ad time. 3: for faster conversion times, the selection of another clock source is recommended. 4: for device frequencies above 1 mhz, the device must be in sleep for the entire conversion or the a/d accuracy may be out of specification.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 173 16.4 a/d conversions figure 16-3 shows the operation of the a/d converter after the go bit has been set. clearing the go/done bit during a conversion will abort the current conver- sion. the a/d result register pair will not be updated with the partially completed a/d conversion sample. that is, the adresh:adresl registers will continue to contain the value of the last completed conversion (or the last value written to the adresh:adresl reg- isters). after the a/d conversion is aborted, a 2t ad wait is required before the next acquisition is started. after this 2t ad wait, acquisition on the selected channel is automatically started. 16.5 use of the ccp 2 trigger an a/d conversion can be started by the special event trigger of the ccp2 module. this requires that the ccp2m3:ccp2m0 bits (ccp2con<3:0>) be pro- grammed as 1011 and that the a/d module is enabled (adon bit is set). when the trigger occurs, the go/ done bit will be set, starting the a/d conversion, and the timer1 (or timer3) counter will be reset to zero. timer1 (or timer3) is reset to automatically repeat the a/d acquisition period with minimal software overhead (moving adresh/adresl to the desired location). the appropriate analog input channel must be selected and the minimum acquisition done before the special event trigger sets the go/done bit (starts a conver- sion). if the a/d module is not enabled (adon is cleared), the special event trigger will be ignored by the a/d mod- ule, but will still reset the timer1 (or timer3) counter. figure 16-3: a/d conversion t ad cycles note: the go/done bit should not be set in the same instruction that turns on the a/d. t ad 1 t ad 2 t ad 3 t ad 4 t ad 5 t ad 6 t ad 7 t ad 8 t ad 11 set go bit holding capacitor is disconnected from analog input (typically 100 ns) b9 b8 b7 b6 b5 b4 b3 b2 t ad 9 t ad 10 b1 b0 tcy - t ad next q4: adresh/adresl is loaded, go bit is cleared, adif bit is set, holding capacitor is connected to analog input. conversion starts b0
pic18cxx2 ds39026b-page 174 preliminary ? 7/99 microchip technology inc. table 16-3: summary of a/d registers name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 value on por, bor value on all other resets intcon gie/ gieh peie/ giel tmr0ie int0ie rbie tmr0if int0if rbif 0000 000x 0000 000u pir1 pspif (1) adif rcif txif sspif ccp1if tmr2if tmr1if 0000 0000 0000 0000 pie1 pspie (1) adie rcie txie sspie ccp1ie tmr2ie tmr1ie 0000 0000 0000 0000 ipr1 pspip (1) adip rcip txip sspip ccp1ip tmr2ip tmr1ip 0000 0000 0000 0000 pir2 bclif lv d if tmr3if ccp2if ---- 0000 ---- 0000 pie2 bclie lv d ie tmr3ie ccp2ie ---- 0000 ---- 0000 ipr2 bclip lv d ip tmr3ip ccp2ip ---- 0000 ---- 0000 adresh a/d result register xxxx xxxx uuuu uuuu adresl a/d result register xxxx xxxx uuuu uuuu adcon0 adcs1 adcs0 chs2 chs1 chs0 go/ done adon 0000 00-0 0000 00-0 adcon1 adfm adcs2 pcfg3 pcfg2 pcfg1 pcfg0 ---- -000 ---- -000 porta ra6 ra5 ra4 ra3 ra2 ra1 ra0 --0x 0000 --0u 0000 trisa porta data direction register --11 1111 --11 1111 porte re2re1re0 ---- -000 ---- -000 late l at e 2 l at e 1 l at e0 ---- -xxx ---- -uuu trise ibf obf ibov pspmode porte data direction bits 0000 -111 0000 -111 legend: x = unknown, u = unchanged, = unimplemented read as '0'. shaded cells are not used for a/d conversion. note 1: the pspif, pspie and pspip bits are reserved on the pic18c2x2 devices. always maintain these bits clear.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 175 17.0 low voltage detect in many applications, the ability to determine if the device voltage (v dd ) is below a specified voltage level is a desirable feature. a window of operation for the application can be created, where the application soft- ware can do "housekeeping tasks" before the device voltage exits the valid operating range. this can be done using the low voltage detect module. this module is a software programmable circuitry, where a device voltage trip point can be specified. when the voltage of the device becomes lower then the specified point, an interrupt flag is set. if the interrupt is enabled, the program execution will branch to the inter- rupt vector address and the software can then respond to that interrupt source. the low voltage detect circuitry is completely under software control. this allows the circuitry to be "turned off" by the software, which minimizes the current con- sumption for the device. figure 17-1 shows a possible application voltage curve (typically for batteries). over time, the device voltage decreases. when the device voltage equals voltage v a , the lvd logic generates an interrupt. this occurs at time t a . the application software then has the time until the device voltage is no longer in valid operating range to shut down the system. voltage point v b is the mini- mum valid operating voltage specification. this occurs at time t b . t b - t a is the total time for shutdown. figure 17-1: typical low voltage detect application time voltage v a v b t a t b v a = lvd trip point v b = minimum valid device operating voltage legend:
pic18cxx2 ds39026b-page 176 preliminary ? 7/99 microchip technology inc. figure 17-2 shows the block diagram for the lvd mod- ule. a comparator uses an internally generated refer- ence voltage as the set point. when the selected tap output of the device voltage crosses the set point (is lower than), the lvdif bit is set. each node in the resist er divider represents a trip point voltage. the trip point voltage is the minimum supply voltage level at which the device can operate before the lvd module asserts an interrupt. when the supply voltage is equal to the trip point, the voltage tapped off of the resistor array is equal to the voltage generated by the internal voltage reference module. the comparator then generates an interrupt signal set- ting the lvdif bit. this voltage is software programma- ble to any one of 16 values (see figure 17-2). the trip point is selected by programming the lvdl3:lvdl0 bits (lvdcon<3:0>). figure 17-2: low voltage detect (lvd) block diagram lv d if v dd 16 to 1 mux lv d e n lvd control register internally generated reference voltage lv d i n
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 177 17.1 control register the low voltage detect control register controls the operation of the low voltage detect circuitry. register 17-1: lvdcon register u-0 u-0 r-0 r/w-0 r/w-0 r/w-1 r/w-0 r/w-1 irvst lvden lvdl3 lvdl2 lvdl1 lvdl0 bit 7 bit 0 bit 7:6 unimplemented: read as '0' bit 5 irvst: internal reference voltage stable flag bit 1 = indicates that the low voltage detect logic will generate the interrupt flag at the specified voltage range. 0 = indicates that the low voltage detect logic will not generate the interrupt flag at the specified voltage range and the lvd interrupt should not be enabled bit 4 lvden: low-voltage detect power enable bit 1 = enables lvd, powers up lvd circuit 0 = disables lvd, powers down lvd circuit bit 3:0 lvd l 3 : lvd l 0: low voltage detection limit bits 1111 = external analog input is used (input comes from the lvdin pin) 1110 = 4.5v min - 4.77v max. 1101 = 4.2v min - 4.45v max. 1100 = 4.0v min - 4.24v max. 1011 = 3.8v min - 4.03v max. 1010 = 3.6v min - 3.82v max. 1001 = 3.5v min - 3.71v max. 1000 = 3.3v min - 3.50v max. 0111 = 3.0v min - 3.18v max. 0110 = 2.8v min - 2.97v max. 0101 = 2.7v min - 2.86v max. 0100 = 2.5v min - 2.65v max. 0011 = 2.4v min - 2.54v max. 0010 = 2.2v min - 2.33v max. 0001 = 2.0v min - 2.12v max. 0000 = 1.8v min - 1.91v max. note: lvdl3:lvdl0 modes which result in a trip point below the valid operating voltage of the device are not tested. legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset
pic18cxx2 ds39026b-page 178 preliminary ? 7/99 microchip technology inc. 17.2 operatio n depending on the power source for the device voltage, the voltage normally decreases relatively slowly. this means that the lvd module does not need to be con- stantly operating. to decrease the current require- ments, the lvd circuitry only needs to be enabled for short periods, where the voltage is checked. after doing the check, the lvd module may be disabled. each time that the lvd module is enabled, the circuitry requires some time to stabilize. after the circuitry has stabilized, all status flags may be cleared. the module will then indicate the proper state of the system. the following steps are needed to setup the lvd module: 1. write the value to the lvdl3:lvdl0 bits (lvd- con register), which selects the desired lvd trip point. 2. ensure that lvd interrupts are disabled (the lvdie bit is cleared or the gie bit is cleared). 3. enable the lvd module (set the lvden bit in the lvdcon register). 4. wait for the lvd module to stabilize (the irvst bit to become set). 5. clear the lvd interrupt flag, which may have falsely become set until the lvd module has sta- bilized (clear the lvdif bit). 6. enable the lvd interrupt (set the lvdie and the gie bits). figure 17-3 shows typical waveforms that the lvd module may be used to detect. figure 17-3: low voltage detect waveforms . v lvd v dd lv d i f v lvd v dd enable lvd internally generated 50 ms lvdif may not be set enable lvd 50 ms lv d i f lvdif cleared in software lvdif cleared in software lvdif cleared in software, case 1: case 2: lvdif remains set since lvd condition still exists reference stable internally generated reference stable
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 179 17.2.1 reference voltage set point the internal reference voltage of the lvd module may be used by other internal circuitry (the programmable brown-out reset). if these circuits are disabled (lower current consumption), the reference voltage circuit requires a time to become stable before a low voltage condition can be reliably detected. this time is invariant of system clock speed. this start-up time is specified in electrical specification parameter #36. the low-voltage interrupt flag will not be enabled until a stable reference voltage is reached. refer to the waveform in figure 17- 3. 17.2.2 current consumption when the module is enabled, the lvd comparator and voltage divider are enabled and will consume static cur- rent. the voltage divider can be tapped from multiple places in the resistor array. total current consumption, when enabled, is specified in electrical specification parameter #d022b. 17.3 operation during sleep when enabled, the lvd circuitry continues to operate during sleep. if the device voltage crosses the trip point, the lvdif bit will be set and the device will wake-up from sleep. device execution will continue from the interrupt vector address if interrupts have been globally enabled. 17.4 effects of a reset a device reset forces all registers to their reset state. this forces the lvd module to be turned off.
pic18cxx2 ds39026b-page 180 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 181 18.0 special features of the cpu there are several features intended to maximize sys- tem reliability, minimize cost through elimination of external components, provide power saving operating modes and offer code protection. these are: ? osc selection ? reset - power-on reset (por) - power-up timer (pwrt) - oscillator start-up timer (ost) - brown-out reset (bor) ? interrupts ? watchdog timer (wdt) ? sleep ? code protection ? id locations ? in-circuit serial programming these devices have a watchdog timer, which is per- manently enabled via the configuration bits or software- controlled. it runs off its own rc oscillator for added reliability. there are two timers that offer necessary delays on power-up. one is the oscillator start-up timer (ost), intended to keep the chip in reset until the crystal oscillator is stable. the other is the power-up timer (pwrt), which provides a fixed delay on power- up only, designed to keep the part in reset while the power supply stabilizes. with these two timers on-chip, most applications need no external reset circuitry. sleep mode is designed to offer a very low current power-down mode. the user can wake-up from sleep through external reset, watchdog timer wake-up or through an interrupt. several oscillator options are also made available to allow the part to fit the application. the rc oscillator option saves system cost, while the lp crystal option saves power. a set of configuration bits are used to select various options. 18.1 c onfiguration bits the configuration bits can be programmed (read as '0') or left unprogrammed (read as '1') to select various device configurations. these bits are mapped starting at program memory location 300000h. the user will note that address 300000h is beyond the user program memory space. in fact, it belongs to the configuration memory space (300000h - 3fffffh), which can only be accessed using table reads and table writes. table 18-1: configuration bits and device ids filename bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 default/ unprogrammed value 300000h config1l cp cp cp cp cp cp cp cp 1111 1111 300001h config1h oscsen fosc2 fosc1 fosc0 111- -111 300002h config2l borv1 borv0 boden pwrten ---- 1111 300003h config2h wdtps2 wdtps1 wdtps0 wdten ---- 1111 300005h config3h ccp2mx ---- ---1 300006h config4l lvenstvren ---- --11 3ffffeh devid1 dev2 dev1 dev0 rev4 rev3 rev2 rev1 rev0 0000 0000 3fffffh devid2 dev10 dev9 dev8 dev7 dev6 dev5 dev4 dev3 0000 0010 legend: x = unknown, u = unchanged, - = unimplemented, q = value depends on condition, grayed cells are unimplemented read as 0
pic18cxx2 ds39026b-page 182 preliminary ? 7/99 microchip technology inc. register 18-1: configuration register 1 high (config1h: byte address 300001h) register 18-2: configuration register 1 low (config1l: byte address 300000h) r/p-1 r/p-1 r/p-1 u-0 u-0 r/p-1 r/p-1 r/p-1 reserved reserved osc se n fosc2 fosc1 fosc0 bit 7 bit 0 bit 7-6 reserved: read as 1 bit 5 osc se n : oscillator system clock switch enable bit 1 = oscillator system clock switch option is disabled (main oscillator is source) 0 = oscillator system clock switch option is enabled ( oscillator switching is enabled) bit 4-3 reserved: read as 0 bit 2-0 fosc2:fosc0 : oscillator selection bits 111 = rc oscillator w/ osc2 configured as ra6 110 = hs oscillator with pll enabled/clock frequency = (4 x fosc) 101 = ec oscillator w/ osc2 configured as ra6 100 = ec oscillator w/ osc2 configured as divide by 4 clock output 011 = rc oscillator 010 = hs oscillator 001 = xt oscillator 000 = lp oscillator legend: r = readable bit p = programmable bit u = unimplemented bit, read as 0 - n = value when device is unprogrammed u = unchanged from programmed state r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 r/p-1 cp cp cp cp cp cp cp cp bit 7 bit 0 cp: code protection bits (apply when in code protected microcontroller mode) 1 = program memory code protection off 0 = all of program memory code protected legend: r = readable bit p = programmable bit u = unimplemented bit, read as 0 - n = value when device is unprogrammed u = unchanged from programmed state
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 183 register 18-3: configuration register 2 high (config2h: byte address 300003h) register 18-4: configuration register 2 low (config2l: byte address 300002h) u-0 u-0 u-0 u-0 r/p-1 r/p-1 r/p-1 r/p-1 wdtps2 wdtps1 wdtps0 wdten bit 7 bit 0 bit 7-4 reserved: read as 0 bit 3-1 wdtps2:wdtps0: watchdog timer postscale select bits 000 = 1:128 001 = 1:64 010 = 1:32 011 = 1:16 100 = 1:8 101 = 1:4 110 = 1:2 111 = 1:1 bit 0 wdten: watchdog timer enable bit 1 = wdt enabled 0 = wdt disabled (control is placed on the swdten bit) legend: r = readable bit p = programmable bit u = unimplemented bit, read as 0 - n = value when device is unprogrammed u = unchanged from programmed state u-0 u-0 u-0 u-0 r/p-1 r/p-1 r/p-1 r/p-1 borv1 borv0 boren pwrte n bit 7 bit 0 bit 7-4 reserved: read as 0 bit 3-2 borv1:borv0: brown-out reset voltage bits 11 = v bor set to 2.5v 10 = v bor set to 2.7v 01 = v bor set to 4.2v 00 = v bor set to 4.5v bit 1 boren: brown-out reset enable bit (1) 1 = brown-out reset enabled 0 = brown-out reset disabled note: enabling brown-out reset automatically enables the power-up timer (pwrt), regardless of the value of bit pwrte n . ensure the power-up timer is enabled any- time brown-out reset is enabled. bit 0 pwrte n : power-up timer enable bit (1) 1 = pwrt disabled 0 = pwrt enabled note: enabling brown-out reset automatically enables the power-up timer (pwrt), regardless of the value of bit pwrte . ensure the power-up timer is enabled any- time brown-out reset is enabled. legend: r = readable bit p = programmable bit u = unimplemented bit, read as 0 - n = value when device is unprogrammed u = unchanged from programmed state
pic18cxx2 ds39026b-page 184 preliminary ? 7/99 microchip technology inc. register 18-5: configuration register 3 high (config3h: byte address 300005h) register 18-6: configuration register 4 low (config3h: byte address 300006h) u-0 u-0 u-0 u-0 u-0 u-0 u-0 r/p-1 ccp2mx bit 7 bit 0 bit 7-1 reserved: read as 0 bit 0 ccp2mx: ccp2 mux bit 1 = ccp2 input/output is multiplexed with rc1 0 = ccp2 input/output is multiplexed with rb3 legend: r = readable bit p = programmable bit u = unimplemented bit, read as 0 - n = value when device is unprogrammed u = unchanged from programmed state u-0 u-0 u-0 u-0 u-0 u-0 r/p-1 r/p-1 reserved stvren bit 7 bit 0 bit 7-2 reserved: read as 0 bit 1 reserved: maintain this bit set. bit 0 stvren: stack full/underflow reset enable bit 1 = stack full/underflow will cause reset 0 = stack full/underflow will not cause reset legend: r = readable bit p = programmable bit u = unimplemented bit, read as 0 - n = value when device is unprogrammed u = unchanged from programmed state
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 185 18.2 watchdog timer (wdt) the watchdog timer is a free running on-chip rc oscil- lator, which does not require any external components. this rc oscillator is separate from the rc oscillator of the osc1/clki pin. that means that the wdt will run, even if the clock on the osc1/clki and osc2/clko/ ra6 pins of the device has been stopped, for example, by execution of a sleep instruction. during normal operation, a wdt time-out generates a device reset (watchdog timer reset). if the device is in sleep mode, a wdt time-out causes the device to wake-up and continue with normal operation (watch- dog timer wake-up). the to bit in the rcon register will be cleared upon a wdt time-out. the watchdog timer is enabled/disabled by a device configuration bit. if the wdt is enabled, software exe- cution may not disable this function. when the wdten configuration bit is cleared, the swdten bit enables/ disables the operation of the wdt. the wdt time-out period values may be found in the electrical specifications section under parameter #31. values for the wdt postscaler may be assigned using the configuration bits. 18.2.1 control register register 18-7 shows the wdtcon register. this is a readable and writable register, which contains a control bit that allows software to override the wdt enable configuration bit, only when the configuration bit has disabled the wdt. register 18-7 wdtcon register note: the clrwdt and sleep instructions clear the wdt and the postscaler if assigned to the wdt, and prevent it from timing out and generating a device reset condition. note: when a clrwdt instruction is executed and the prescaler is assigned to the wdt, the prescaler count will be cleared, but the prescaler assignment is not changed. u-0 u-0 u-0 u-0 u-0 u-0 u-0 r/w-0 swdten bit 7 bit 0 bit 7:1 unimplemented : read as 0 bit 0 swdten: software controlled watchdog timer enable bit 1 = watchdog timer is on 0 = watchdog timer is turned off if the wdten configuration bit in the configuration register = 0 legend: r = readable bit w = writable bit u = unimplemented bit, read as 0 - n = value at por reset
pic18cxx2 ds39026b-page 186 preliminary ? 7/99 microchip technology inc. 18.2.2 wdt postscaler the wdt has a postscaler that can extend the wdt reset period. the postscaler is selected at the time of the device programming, by the value written to the config2h configuration register. figure 18-1: watchdog timer block diagram figure 18-2: summary of watchdog timer registers name bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 config2h wdtps2 wdtps2 wdtps0 wdten rcon ipen lwrt ri to pd por bor wdtcon swdten legend: shaded cells are not used by the watchdog timer. postscaler wdt timer wdten 8 - to - 1 mux wdtps2:wdtps0 wdt time-out 8 swdten bit note: wdps2:wdps0 are bits in a configuration register. configuration bit
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 187 18.3 power-down mode (sleep) power-down mode is entered by executing a sleep instruction. if enabled, the watchdog timer will be cleared, but keeps running, the pd bit (rcon<3>) is cleared, the to (rcon<4>) bit is set, and the oscillator driver is turned off. the i/o ports maintain the status they had before the sleep instruction was executed (driving high, low or hi-impedance). for lowest current consumption in this mode, place all i/o pins at either v dd or v ss , ensure no external cir- cuitry is drawing current from the i/o pin, power-down the a/d and disable external clocks. pull all i/o pins that are hi-impedance inputs, high or low externally, to avoid switching currents caused by floating inputs. the t0cki input should also be at v dd or v ss for lowest current consumption. the contribution from on-chip pull-ups on portb should be considered. the mclr pin must be at a logic high level (v ihmc ). 18.3.1 wake-up from sleep the device can wake up from sleep through one of the following events: 1. external reset input on mclr pin. 2. watchdog timer wake-up (if wdt was enabled). 3. interrupt from int pin, rb port change or a peripheral interrupt. the following peripheral interrupts can wake the device from sleep: 1. psp read or write. 2. tmr1 interrupt. timer1 must be operating as an asynchronous counter. 3. tmr3 interrupt. timer3 must be operating as an asynchronous counter. 4. ccp capture mode interrupt. 5. special event trigger (timer1 in asynchronous mode using an external clock). 6. mssp (start/stop) bit detect interrupt. 7. mssp transmit or receive in slave mode (spi/ i 2 c). 8. usart rx or tx (synchronous slave mode). 9. a/d conversion (when a/d clock source is rc). other peripherals cannot generate interrupts, since during sleep, no on-chip clocks are present. external mclr reset will cause a device reset. all other events are considered a continuation of program execution and will cause a "wake-up". the to and pd bits in the rcon register can be used to determine the cause of the device reset. the pd bit, which is set on power-up, is cleared when sleep is invoked. the to bit is cleared, if a wdt time-out occurred (and caused wake-up). when the sleep instruction is being executed, the next instruction (pc + 2) is pre-fetched. for the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be set (enabled). wake-up is regardless of the state of the gie bit. if the gie bit is clear (disabled), the device continues execution at the instruction after the sleep instruction. if the gie bit is set (enabled), the device executes the instruction after the sleep instruction and then branches to the inter- rupt address. in cases where the execution of the instruction following sleep is not desirable, the user should have a nop after the sleep instruction.
pic18cxx2 ds39026b-page 188 preliminary ? 7/99 microchip technology inc. 18.3.2 wake-up using interrupts when global interrupts are disabled (gie cleared) and any interrupt source has both its interrupt enable bit and interrupt flag bit set, one of the following will occur: ? if an interrupt condition (interrupt flag bit and inter- rupt enable bits are set) occurs before the execu- tion of a sleep instruction, the sleep instruction will complete as a nop. therefore, the wdt and wdt postscaler will not be cleared, the to bit will not be set and pd bits will not be cleared. ? if the interrupt condition occurs during or after the execution of a sleep instruction, the device will immediately wake up from sleep. the sleep instruction will be completely executed before the wake-up. therefore, the wdt and wdt postscaler will be cleared, the to bit will be set and the pd bit will be cleared. even if the flag bits were checked before executing a sleep instruction, it may be possible for flag bits to become set before the sleep instruction completes. to determine whether a sleep instruction executed, test the pd bit. if the pd bit is set, the sleep instruction was executed as a nop. to ensure that the wdt is cleared, a clrwdt instruc- tion should be executed before a sleep instruction. figure 18-3: wake-up from sleep through interrupt (1,2) q1 q2 q3 q4 q1 q2 q3 q4 q1 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 q1 q2 q3 q4 osc1 clkout ( 4 ) int pin intf flag (intcon<1>) gieh bit (intcon<7>) instruction flow pc instruction fetched instruction executed pc pc+2 pc+4 inst(pc) = sleep inst(pc - 1) inst(pc + 2) sleep processor in sleep interrupt latency ( 3 ) inst(pc + 4) inst(pc + 2) inst(0008h) inst(000ah) inst(0008h) dummy cycle pc + 4 0008h 000ah dummy cycle t ost ( 2 ) pc+4 note 1: xt, hs or lp oscillator mode assumed. 2: gie = '1' assumed. in this case, after wake- up, the processor jumps to the interrupt routine. if gie = '0', execution will continue in-line. 3: t ost = 1024t osc (drawing not to scale) this delay will not occur for rc and ec osc modes. 4: clkout is not available in these osc modes, but shown here for timing reference.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 189 18.4 program verification/code protection if the code protection bit(s) have not been pro- grammed, the on-chip program memory can be read out for verification purposes. 18.5 id locations five memory locations (200000h - 200004h) are desig- nated as id locations, where the user can store check- sum or other code-identification numbers. these locations are accessible during normal execution through the tblrd instruction or during program/ver- ify. the id locations can be read when the device is code protected. 18.6 in-circuit serial programming pic18cxxx microcontrollers can be serially pro- grammed while in the end application circuit. this is simply done with two lines for clock and data, and three other lines for power, ground and the programming volt- age. this allows customers to manufacture boards with unprogrammed devices, and then program the micro- controller just before shipping the product. this also allows the most recent firmware or a custom firmware to be programmed. note: microchip technology does not recom- mend code protecting windowed devices.
pic18cxx2 ds39026b-page 190 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 191 19.0 instruction set summary the pic18cxxx instruction set adds many enhance- ments to the previous picmicro instruction sets, while maintaining an easy migration from these picmicro instruction sets. most instructions are a single program memory word (16-bits), but there are three instructions that require two program memory locations. each single word instruction is a 16-bit word divided into an opcode, which specifies the instruction type and one or more operands, which further specify the operation of the instruction. the instruction set is highly orthogonal and is grouped into four basic categories: ? byte-oriented operations ? bit-oriented operations ? literal operations ? control operations the pic18cxxx instruction set summary in table 19-2 lists byte-oriented , bit-oriented , literal and control operations. table 19-1 shows the opcode field descriptions. most byte-oriented instructions have three operands: 1. the file register (specified by the value of f) 2. the destination of the result (specified by the value of d) 3. the accessed memory (specified by the value of a) 'f' represents a file register designator and 'd' repre- sents a destination designator. the file register desig- nator specifies which file register is to be used by the instruction. the destination designator specifies where the result of the operation is to be placed. if 'd' is zero, the result is placed in the wreg register. if 'd' is one, the result is placed in the file register specified in the instruction. all bit-oriented instructions have three operands: 1. the file register (specified by the value of f) 2. the bit in the file register (specified by the value of b) 3. the accessed memory (specified by the value of a) 'b' represents a bit field designator which selects the number of the bit affected by the operation, while 'f' rep- resents the number of the file in which the bit is located. the literal instructions may use some of the following operands: ? a literal value to be loaded into a file register (specified by the value of k) ? the desired fsr register to load the literal value into (specified by the value of f) ? no operand required (specified by the value of ) the control instructions may use some of the following operands: ? a program memory address (specified by the value of n) ? the mode of the call or return instructions (spec- ified by the value of s) ? the mode of the table read and table write instructions (specified by the value of m) ? no operand required (specified by the value of ) all instructions are a single word, except for three dou- ble word instructions. these three instructions were made double word instructions so that all the required information is available in these 32-bits. in the second word, the 4-msbs are 1s. if this second word is exe- cuted as an instruction (by itself), it will execute as a nop . all single word instructions are executed in a single instruction cycle, unless a conditional test is true or the program counter is changed as a result of the instruc- tion. in these cases, the execution takes two instruction cycles with the additional instruction cycle(s) executed as a nop . the double word instructions execute in two instruction cycles. one instruction cycle consists of four oscillator periods. thus, for an oscillator frequency of 4 mhz, the normal instruction execution time is 1 m s. if a conditional test is true or the program counter is changed as a result of an instruction, the instruction execution time is 2 m s. two word branch instructions (if true) would take 3 m s. figure 19-1 shows the general formats that the instruc- tions can have. all examples use the following format to represent a hexadecimal number: 0xhh where h signifies a hexadecimal digit. the instruction set summary, shown in table 19-2, lists the instructions recognized by the microchip assembler (mpasm). section 19.1 provides a description of each instruction.
pic18cxx2 ds39026b-page 192 preliminary ? 7/99 microchip technology inc. table 19-1: opcode field descriptions field description a ram access bit a = 0: ram location in access ram (bsr register is ignored) a = 1: ram bank is specified by bsr register bbb bit address within an 8-bit file register (0 to 7) bsr bank select register. used to select the current ram bank. d destination select bit; d = 0: store result in wreg, d = 1: store result in file register f. dest destination either the wreg register or the specified register file location f 8-bit register file address (0x00 to 0xff) fs 12-bit register file address (0x000 to 0xfff). this is the source address. fd 12-bit register file address (0x000 to 0xfff). this is the destination address. k literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value) label label name mm the mode of the tblptr register for the table read and table write instructions only used with table read and table write instructions: * no change to register (such as tblptr with table reads and writes) *+ post-increment register (such as tblptr with table reads and writes) *- post-decrement register (such as tblptr with table reads and writes) +* pre-increment register (such as tblptr with table reads and writes) n the relative address (2s complement number) for relative branch instructions, or the direct address for call/branch and return instructions prodh product of multiply high byte prodl product of multiply low byte s fast call / return mode select bit. s = 0: do not update into/from shadow registers s = 1: certain registers loaded into/from shadow registers (fast mode) u unused or unchanged wreg working register (accumulator) x don't care (0 or 1) the assembler will generate code with x = 0. it is the recommended form of use for compatibility with all microchip software tools. tblptr 21-bit table pointer (points to a program memory location) tablat 8-bit table latch tos top of stack pc program counter pcl program counter low byte pch program counter high byte pclath program counter high byte latch pclatu program counter upper byte latch gie global interrupt enable bit wdt watchdog timer to time-out bit pd power-down bit c, dc, z, ov, n alu status bits carry, digit carry, zero, overflow, negative [ ] optional ( ) contents ? assigned to < > register bit field ? in the set of italics user defined term (font is courier)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 193 figure 19-1: general format for instructions byte-oriented file register operations 15 10 9 8 7 0 d = 0 for result destination to be wreg register opcode d a f (file #) d = 1 for result destination to be file register (f) a = 0 to force access bank bit-oriented file register operations 15 12 11 9 8 7 0 opcode b (bit #) a f (file #) b = 3-bit position of bit in file register (f) literal operations 15 8 7 0 opcode k (literal) k = 8-bit immediate value byte to byte move operations (2-word) 15 12 11 0 opcode f (source file #) call, goto and branch operations 15 8 7 0 opcode n<7:0> (literal) n = 20-bit immediate value a = 1 for bsr to select bank f = 8-bit file register address a = 0 to force access bank a = 1 for bsr to select bank f = 8-bit file register address 15 12 11 0 1111 n<19:8> (literal) 15 12 11 0 1111 f (destination file #) f = 12-bit file register address control operations example instruction addwf myreg, w, b movff myreg1, myreg2 bsf myreg, bit, b movlw 0x7f goto label 15 8 7 0 opcode n<7:0> (literal) 15 12 11 0 n<19:8> (literal) call myfunc 15 11 10 0 opcode n<10:0> (literal) s = fast bit bra myfunc 15 8 7 0 opcode n<7:0> (literal) bc myfunc s
pic18cxx2 ds39026b-page 194 preliminary ? 7/99 microchip technology inc. table 19-2: pic18cxxx instruction set mnemonic, operands description cycles 16-bit instruction word status affected notes msb lsb byte-oriented file register operations addwf addwfc andwf clrf comf cpfseq cpfsgt cpfslt decf decfsz dcfsnz incf incfsz infsnz iorwf movf movff movwf mulwf negf rlcf rlncf rrcf rrncf setf subfwb subwf subwfb swapf tstfsz xorwf f, d, a f, d, a f, d, a f, a f, d, a f, a f, a f, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f, d, a f s , f d f, a f, a f, a f, d, a f, d, a f, d, a f, d, a f, a f, d, a f, d, a f, d, a f, d, a f, a f, d, a add wreg and f add wreg and carry bit to f and wreg with f clear f complement f compare f with wreg, skip = compare f with wreg, skip > compare f with wreg, skip < decrement f decrement f, skip if 0 decrement f, skip if not 0 increment f increment f, skip if 0 increment f, skip if not 0 inclusive or wreg with f move f move f s (source) to 1st word f d (destination)2nd word move wreg to f multiply wreg with f negate f rotate left f through carry rotate left f (no carry) rotate right f through carry rotate right f (no carry) set f subtract f from wreg with borrow subtract wreg from f subtract wreg from f with borrow swap nibbles in f test f, skip if 0 exclusive or wreg with f 1 1 1 1 1 1 (2 or 3) 1 (2 or 3) 1 (2 or 3) 1 1 (2 or 3) 1 (2 or 3) 1 1 (2 or 3) 1 (2 or 3) 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 (2 or 3) 1 0010 0010 0001 0110 0001 0110 0110 0110 0000 0010 0100 0010 0011 0100 0001 0101 1100 1111 0110 0000 0110 0011 0100 0011 0100 0110 0101 0101 0101 0011 0110 0001 01da 00da 01da 101a 11da 001a 010a 000a 01da 11da 11da 10da 11da 10da 00da 00da ffff ffff 111a 001a 110a 01da 01da 00da 00da 100a 01da 11da 10da 10da 011a 10da ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff c, dc, z, ov, n c, dc, z, ov, n z, n z z, n none none none c, dc, z, ov, n none none c, dc, z, ov, n none none z, n z, n none none none c, dc, z, ov, n c, z, n z, n c, z, n z, n none c, dc, z, ov, n c, dc, z, ov, n c, dc, z, ov, n none none z, n 1, 2 1, 2 1,2 2 1, 2 4 4 1, 2 1, 2, 3, 4 1, 2, 3, 4 1, 2 1, 2, 3, 4 4 1, 2 1, 2 1 1, 2 1, 2 1, 2 1, 2 4 1, 2 bit-oriented file register operations bcf bsf btfsc btfss btg f, b, a f, b, a f, b, a f, b, a f, d, a bit clear f bit set f bit test f, skip if clear bit test f, skip if set bit toggle f 1 1 1 (2 or 3) 1 (2 or 3) 1 1001 1000 1011 1010 0111 bbba bbba bbba bbba bbba ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff none none none none none 1, 2 1, 2 3, 4 3, 4 1, 2 note 1: when a port register is modified as a function of itself (e.g., movf portb, 1, 0 ), the value used will be that value present on the pins themselves. for example, if the data latch is '1' for a pin configured as input and is driven low by an external device, the data will be written back with a '0'. 2: if this instruction is executed on the tmr0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned. 3: if program counter (pc) is modified or a conditional test is true, the instruction requires two cycles. the second cycle is executed as a nop . 4: some instructions are 2 word instructions. the second word of these instruction will be executed as a nop , unless the first word of the instruction retrieves the information embedded in these 16-bits. this ensures that all program memory locations have a valid instruction. 5: if the table write starts the write cycle to internal memory, the write will continue until terminated.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 195 control operations bc bn bnc bnn bnov bnz bov bra bz call clrwdt daw goto nop nop pop push rcall reset retfie retlw return sleep n n n n n n n n n n, s n n s k s branch if carry branch if negative branch if not carry branch if not negative branch if not overflow branch if not zero branch if overflow branch unconditionally branch if zero call subroutine1st word 2nd word clear watchdog timer decimal adjust wreg go to address1st word 2nd word no operation no operation (note 4) pop top of return stack (tos) push top of return stack (tos) relative call software device reset return from interrupt enable return with literal in wreg return from subroutine go into standby mode 1 (2) 1 (2) 1 (2) 1 (2) 1 (2) 2 1 (2) 1 (2) 1 (2) 2 1 1 2 1 1 1 1 2 1 2 2 2 1 1110 1110 1110 1110 1110 1110 1110 1101 1110 1110 1111 0000 0000 1110 1111 0000 1111 0000 0000 1101 0000 0000 0000 0000 0000 0010 0110 0011 0111 0101 0001 0100 0nnn 0000 110s kkkk 0000 0000 1111 kkkk 0000 xxxx 0000 0000 1nnn 0000 0000 1100 0000 0000 nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn kkkk kkkk 0000 0000 kkkk kkkk 0000 xxxx 0000 0000 nnnn 1111 0001 kkkk 0001 0000 nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn nnnn kkkk kkkk 0100 0111 kkkk kkkk 0000 xxxx 0110 0101 nnnn 1111 000s kkkk 001s 0011 none none none none none none none none none none to , pd c none none none none none none all gie/gieh, peie/giel none none to , pd table 19-2: pic18cxxx instruction set (c ont.d) mnemonic, operands description cycles 16-bit instruction word status affected notes msb lsb note 1: when a port register is modified as a function of itself (e.g., movf portb, 1, 0 ), the value used will be that value present on the pins themselves. for example, if the data latch is '1' for a pin configured as input and is driven low by an external device, the data will be written back with a '0'. 2: if this instruction is executed on the tmr0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned. 3: if program counter (pc) is modified or a conditional test is true, the instruction requires two cycles. the second cycle is executed as a nop . 4: some instructions are 2 word instructions. the second word of these instruction will be executed as a nop , unless the first word of the instruction retrieves the information embedded in these 16-bits. this ensures that all program memory locations have a valid instruction. 5: if the table write starts the write cycle to internal memory, the write will continue until terminated.
pic18cxx2 ds39026b-page 196 preliminary ? 7/99 microchip technology inc. literal operations addlw andlw iorlw lfsr movlb movlw mullw retlw sublw xorlw k k k f, k k k k k k k add literal and wreg and literal with wreg inclusive or literal with wreg move literal (12-bit)1st word to fsrx2nd word move literal to bsr<3:0> move literal to wreg multiply literal with wreg return with literal in wreg subtract wreg from literal exclusive or literal with wreg 1 1 1 2 1 1 1 2 1 1 0000 0000 0000 1110 1111 0000 0000 0000 0000 0000 0000 1111 1011 1001 1110 0000 0001 1110 1101 1100 1000 1010 kkkk kkkk kkkk 00ff kkkk 0000 kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk c, dc, z, ov, n z, n z, n none none none none none c, dc, z, ov, n z, n data memory ? program memory operations tblrd* tblrd*+ tblrd*- tblrd+* tblwt* tblwt*+ tblwt*- tblwt+* table read table read with post-increment table read with post-decrement table read with pre-increment table write table write with post-increment table write with post-decrement table write with pre-increment 2 2 (5) 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 1000 1001 1010 1011 1100 1101 1110 1111 none none none none none none none none table 19-2: pic18cxxx instruction set (c ont.d) mnemonic, operands description cycles 16-bit instruction word status affected notes msb lsb note 1: when a port register is modified as a function of itself (e.g., movf portb, 1, 0 ), the value used will be that value present on the pins themselves. for example, if the data latch is '1' for a pin configured as input and is driven low by an external device, the data will be written back with a '0'. 2: if this instruction is executed on the tmr0 register (and, where applicable, d = 1), the prescaler will be cleared if assigned. 3: if program counter (pc) is modified or a conditional test is true, the instruction requires two cycles. the second cycle is executed as a nop . 4: some instructions are 2 word instructions. the second word of these instruction will be executed as a nop , unless the first word of the instruction retrieves the information embedded in these 16-bits. this ensures that all program memory locations have a valid instruction. 5: if the table write starts the write cycle to internal memory, the write will continue until terminated.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 197 19.1 i nstruction set addlw add literal to wreg syntax: [ label ] addlw k operands: 0 k 255 operation: (wreg) + k ? wreg status affected: n,ov, c, dc, z encoding: 0000 1111 kkkk kkkk description: the contents of wreg are added to the 8-bit literal 'k' and the result is placed in wreg. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write to wreg example : addlw 0x15 before instruction wreg = 0x10 after instruction wreg = 0x25 addwf add wreg to f syntax: [ label ] addwf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (wreg) + (f) ? dest status affected: n,ov, c, dc, z encoding: 0010 01da ffff ffff description: add wreg to register 'f'. if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored back in reg- ister 'f' (default). if a is 0, the access bank will be selected. if a is 1, the bsr will not be overridden (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : addwf reg, 0, 0 before instruction wreg = 0x17 reg = 0xc2 after instruction wreg = 0xd9 reg = 0xc2
pic18cxx2 ds39026b-page 198 preliminary ? 7/99 microchip technology inc. addwfc add wreg and carry bit to f syntax: [ label ] addwfc f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (wreg) + (f) + (c) ? dest status affected: n,ov, c, dc, z encoding: 0010 00da ffff ffff description: add wreg, the carry flag and data memory location 'f'. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed in data memory location 'f'. if a is 0, the access bank will be selected. if a is 1, the bsr will not be overridden. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : addwfc reg, 0, 1 before instruction carry bit= 1 reg = 0x02 wreg = 0x4d after instruction carry bit= 0 reg = 0x02 wreg = 0x50 andlw and literal with wreg syntax: [ label ] andlw k operands: 0 k 255 operation: (wreg) .and. k ? wreg status affected: n,z encoding: 0000 1011 kkkk kkkk description: the contents of wreg are anded with the 8-bit literal 'k'. the result is placed in wreg. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write to wreg example : andlw 0x5f before instruction wreg = 0xa3 after instruction wreg = 0x03
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 199 andwf and wreg with f syntax: [ label ] andwf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (wreg) .and. (f) ? dest status affected: n,z encoding: 0001 01da ffff ffff description: the contents of wreg are anded with register 'f'. if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored back in register 'f' (default). if a is 0, the access bank will be selected. if a is 1, the bsr will not be overridden (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : andwf reg, 0, 0 before instruction wreg = 0x17 reg = 0xc2 after instruction wreg = 0x02 reg = 0xc2 bc branch if carry syntax: [ label ] bc n operands: -128 n 127 operation: if carry bit is 1 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0010 nnnn nnnn description: if the carry bit is 1, then the pro- gram will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bc 5 before instruction pc = address (here) after instruction if carry = 1; pc = address (here+12) if carry = 0; pc = address (here+2)
pic18cxx2 ds39026b-page 200 preliminary ? 7/99 microchip technology inc. bcf bit clear f syntax: [ label ] bcf f,b,a operands: 0 f 255 0 b 7 a ? [0,1] operation: 0 ? f status affected: none encoding: 1001 bbba ffff ffff description: bit 'b' in register 'f' is cleared. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : bcf flag_reg, 7, 0 before instruction flag_reg = 0xc7 after instruction flag_reg = 0x47 bn branch if negative syntax: [ label ] bn n operands: -128 n 127 operation: if negative bit is 1 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0110 nnnn nnnn description: if the negative bit is 1, then the program will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bn jump before instruction pc = address (here) after instruction if negative = 1; pc = address (jump) if negative = 0; pc = address (here+2)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 201 bnc branch if not carry syntax: [ label ] bnc n operands: -128 n 127 operation: if carry bit is 0 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0011 nnnn nnnn description: if the carry bit is 0, then the pro- gram will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bnc jump before instruction pc = address (here) after instruction if carry = 0; pc = address (jump) if carry = 1; pc = address (here+2) bnn branch if not negative syntax: [ label ] bnn n operands: -128 n 127 operation: if negative bit is 0 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0111 nnnn nnnn description: if the negative bit is 0, then the program will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bnn jump before instruction pc = address (here) after instruction if negative = 0; pc = address (jump) if negative = 1; pc = address (here+2)
pic18cxx2 ds39026b-page 202 preliminary ? 7/99 microchip technology inc. bnov branch if not overflow syntax: [ label ] bnov n operands: -128 n 127 operation: if overflow bit is 0 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0101 nnnn nnnn description: if the overflow bit is 0, then the program will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bnov jump before instruction pc = address (here) after instruction if overflow = 0; pc = address (jump) if overflow = 1; pc = address (here+2) bnz branch if not zero syntax: [ label ] bnz n operands: -128 n 127 operation: if zero bit is 0 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0001 nnnn nnnn description: if the zero bit is 0, then the pro- gram will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bnz jump before instruction pc = address (here) after instruction if zero = 0; pc = address (jump) if zero = 1; pc = address (here+2)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 203 bra unconditional branch syntax: [ label ] bra n operands: -1024 n 1023 operation: (pc) + 2 + 2n ? pc status affected: none encoding: 1101 0nnn nnnn nnnn description: add the 2s complement number 2n to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is a two- cycle instruction. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation example : here bra jump before instruction pc = address (here) after instruction pc = address (jump) bsf bit set f syntax: [ label ] bsf f,b,a operands: 0 f 255 0 b 7 a ? [0,1] operation: 1 ? f status affected: none encoding: 1000 bbba ffff ffff description: bit 'b' in register 'f' is set. if a is 0 access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : bsf flag_reg, 7, 1 before instruction flag_reg= 0x0a after instruction flag_reg= 0x8a
pic18cxx2 ds39026b-page 204 preliminary ? 7/99 microchip technology inc. btfsc bit test file, skip if clear syntax: [ label ] btfsc f,b,a operands: 0 f 255 0 b 7 a ? [0,1] operation: skip if (f) = 0 status affected: none encoding: 1011 bbba ffff ffff description: if bit 'b' in register f' is 0, then the next instruction is skipped. if bit 'b' is 0, then the next instruction fetched during the current instruction execution is discarded, and a nop is executed instead, making this a two- cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here false true btfsc : : flag, 1, 0 before instruction pc = address (here) after instruction if flag<1> = 0; pc = address (true) if flag<1> = 1; pc = address (false) btfss bit test file, skip if set syntax: [ label ] btfss f,b,a operands: 0 f 255 0 b < 7 a ? [0,1] operation: skip if (f) = 1 status affected: none encoding: 1010 bbba ffff ffff description: if bit 'b' in register 'f' is 1 then the next instruction is skipped. if bit 'b' is 1, then the next instruction fetched during the current instruc- tion execution, is discarded and an nop is executed instead, making this a two-cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here false true btfss : : flag, 1, 0 before instruction pc = address (here) after instruction if flag<1> = 0; pc = address (false) if flag<1> = 1; pc = address (true)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 205 btg bit toggle f syntax: [ label ] btg f,b,a operands: 0 f 255 0 b < 7 a ? [0,1] operation: (f ) ? f status affected: none encoding: 0111 bbba ffff ffff description: bit 'b' in data memory location 'f' is inverted. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : btg portc, 4, 0 before instruction: portc = 0111 0101 [0x75] after instruction: portc = 0110 0101 [0x65] bov branch if overflow syntax: [ label ] bov n operands: -128 n 127 operation: if overflow bit is 1 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0100 nnnn nnnn description: if the overflow bit is 1, then the program will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bov jump before instruction pc = address (here) after instruction if overflow = 1; pc = address (jump) if overflow = 0; pc = address (here+2)
pic18cxx2 ds39026b-page 206 preliminary ? 7/99 microchip technology inc. bz branch if zero syntax: [ label ] bz n operands: -128 n 127 operation: if zero bit is 1 (pc) + 2 + 2n ? pc status affected: none encoding: 1110 0000 nnnn nnnn description: if the zero bit is 1, then the pro- gram will branch. the 2s complement number 2n is added to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is then a two-cycle instruction. words: 1 cycles: 1(2) q cycle activity: if jump: q1 q2 q3 q4 decode read literal 'n' process data write to pc no operation no operation no operation no operation if no jump: q1 q2 q3 q4 decode read literal 'n' process data no operation example : here bz jump before instruction pc = address (here) after instruction if zero = 1; pc = address (jump) if zero = 0; pc = address (here+2) call subroutine call syntax: [ label ] call k,s operands: 0 k 1048575 s ? [0,1] operation: (pc) + 4 ? tos, k ? pc<20:1>, if s = 1 (wreg) ? ws, (status) ? statuss, (bsr) ? bsrs status affected: none encoding: 1st word (k<7:0>) 2nd word(k<19:8>) 1110 1111 110s k 19 kkk k 7 kkk kkkk kkkk 0 kkkk 8 description: subroutine call of entire 2m byte memory range. first, return address (pc+ 4) is pushed onto the return stack. if s = 1, the w, sta- tus and bsr registers are also pushed into their respective shadow registers, ws, statuss and bsrs. if 's' = 0, no update occurs (default). then the 20-bit value k is loaded into pc<20:1>. call is a two-cycle instruction. words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal 'k'<7:0>, push pc to stack read literal k<19:8>, write to pc no operation no operation no operation no operation example : here call there,1 before instruction pc = address(here) after instruction pc = address(there) tos = address (here + 4) ws = wreg bsrs= bsr statuss = status
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 207 clrf clear f syntax: [ label ] clrf f,a operands: 0 f 255 a ? [0,1] operation: 000h ? f 1 ? z status affected: z encoding: 0110 101a ffff ffff description: clears the contents of the specified register. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : clrf flag_reg,1 before instruction flag_reg = 0x5a after instruction flag_reg = 0x00 clrwdt clear watchdog timer syntax: [ label ] clrwdt operands: none operation: 000h ? wdt, 000h ? wdt postscaler, 1 ? to, 1 ? pd status affected: to , pd encoding: 0000 0000 0000 0100 description: clrwdt instruction resets the watchdog timer. it also resets the postscaler of the wdt. status bits to and pd are set. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation process data no operation example : clrwdt before instruction wdt counter = ? after instruction wdt counter = 0x00 wdt postscaler = 0 to =1 pd =1
pic18cxx2 ds39026b-page 208 preliminary ? 7/99 microchip technology inc. comf complement f syntax: [ label ] comf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: ? dest status affected: n,z encoding: 0001 11da ffff ffff description: the contents of register 'f' are com- plemented. if 'd' is 0 the result is stored in wreg. if 'd' is 1 the result is stored back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : comf reg, 0, 0 before instruction reg = 0x13 after instruction reg = 0x13 wreg = 0xec (f) cpfseq compare f with wreg, skip if f = wreg syntax: [ label ] cpfseq f,a operands: 0 f 255 a ? [0,1] operation: (f) C (wreg), skip if (f) = (wreg) (unsigned comparison) status affected: none encoding: 0110 001a ffff ffff description: compares the contents of data memory location 'f' to the contents of wreg by performing an unsigned subtraction. if 'f' = wreg , then the fetched instruction is discarded and an nop is executed instead making this a two-cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here cpfseq reg, 0 nequal : equal : before instruction pc address = here wreg = ? reg = ? after instruction if reg = wreg; pc = address (equal) if reg 1 wreg; pc = address (nequal)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 209 cpfsgt compare f with wreg, skip if f > wreg syntax: [ label ] cpfsgt f,a operands: 0 f 255 a ? [0,1] operation: (f) - ( wreg), skip if (f) > (wreg) (unsigned comparison) status affected: none encoding: 0110 010a ffff ffff description: compares the contents of data memory location 'f' to the contents of the wreg by performing an unsigned subtraction. if the contents of 'f' are greater than the contents of , then the fetched instruction is discarded and a nop is executed instead making this a two-cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here cpfsgt reg, 0 ngreater : greater : before instruction pc = address (here) wreg = ? after instruction if reg > wreg; pc = address (greater) if reg wreg; pc = address (ngreater) cpfslt compare f with wreg, skip if f < wreg syntax: [ label ] cpfslt f,a operands: 0 f 255 a ? [0,1] operation: (f) C ( wreg), skip if (f) < (wreg) (unsigned comparison) status affected: none encoding: 0110 000a ffff ffff description: compares the contents of data memory location 'f' to the contents of wreg by performing an unsigned subtraction. if the contents of 'f' are less than the contents of wreg, then the fetched instruction is discarded and a nop is executed instead making this a two-cycle instruction. if a is 0, the access bank will be selected. if a is 1 the bsr will not be overridden (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here cpfslt reg, 1 nless : less : before instruction pc = address (here) w= ? after instruction if reg < wreg; pc = address (less) if reg 3 wreg; pc = address (nless)
pic18cxx2 ds39026b-page 210 preliminary ? 7/99 microchip technology inc. daw decimal adjust wreg register syntax: [ label ] daw operands: none operation: if [wreg<3:0> >9] or [dc = 1] then (wreg<3:0>) + 6 ? wreg<3:0>; else ( wreg<3:0>) ? wreg<3:0>; if [wreg<7:4> >9] or [c = 1] then ( wreg<7:4>) + 6 ? wreg<7:4>; else (wreg<7:4>) ? wreg<7:4>; status affected: c encoding: 0000 0000 0000 0111 description: daw adjusts the eight bit value in wreg resulting from the earlier addition of two variables (each in packed bcd format) and produces a correct packed bcd result. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register wreg process data write wreg example1 : daw before instruction wreg = 0xa5 c=0 dc = 0 after instruction wreg = 0x05 c=1 dc = 0 example 2 : before instruction wreg = 0xce c=0 dc = 0 after instruction wreg = 0x34 c=1 dc = 0 decf decrement f syntax: [ label ] decf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) C 1 ? dest status affected: c,dc,n,ov,z encoding: 0000 01da ffff ffff description: decrement register 'f'. if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : decf cnt, 1, 0 before instruction cnt = 0x01 z=0 after instruction cnt = 0x00 z=1
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 211 decfsz decrement f, skip if 0 syntax: [ label ] decfsz f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) C 1 ? dest, skip if result = 0 status affected: none encoding: 0010 11da ffff ffff description: the contents of register 'f' are dec- remented. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if the result is 0, the next instruc- tion, which is already fetched, is discarded, and a nop is executed instead making it a two-cycle instruction. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here decfsz cnt, 1, 1 goto loop continue before instruction pc = address (here) after instruction cnt = cnt - 1 if cnt = 0; pc = address (continue) if cnt 1 0; pc = address (here+2) dcfsnz decrement f, skip if not 0 syntax: [ label ] dcfsnz f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) C 1 ? dest, skip if result 1 0 status affected: none encoding: 0100 11da ffff ffff description: the contents of register 'f' are dec- remented. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if the result is not 0, the next instruction, which is already fetched, is discarded, and a nop is executed instead making it a two- cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here dcfsnz temp, 1, 0 zero : nzero : before instruction temp = ? after instruction temp = temp - 1, if temp = 0; pc = address (zero) if temp 1 0; pc = address (nzero)
pic18cxx2 ds39026b-page 212 preliminary ? 7/99 microchip technology inc. goto unconditional branch syntax: [ label ] goto k operands: 0 k 1048575 operation: k ? pc<20:1> status affected: none encoding: 1st word (k<7:0>) 2nd word(k<19:8>) 1110 1111 1111 k 19 kkk k 7 kkk kkkk kkkk 0 kkkk 8 description: goto allows an unconditional branch anywhere within entire 2m byte memory range. the 20-bit value k is loaded into pc<20:1>. goto is always a two-cycle instruc- tion. words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal 'k'<7:0>, no operation read literal k<19:8>, write to pc no operation no operation no operation no operation example : goto there after instruction pc = address (there) incf increment f syntax: [ label ] incf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) + 1 ? dest status affected: c,dc,n,ov,z encoding: 0010 10da ffff ffff description: the contents of register 'f' are incremented. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : incf cnt, 1, 0 before instruction cnt = 0xff z=0 c=? dc = ? after instruction cnt = 0x00 z=1 c=1 dc = 1
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 213 incfsz increment f, skip if 0 syntax: [ label ] incfsz f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) + 1 ? dest, skip if result = 0 status affected: none encoding: 0011 11da ffff ffff description: the contents of register 'f' are incremented. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f'. (default) if the result is 0, the next instruc- tion, which is already fetched, is discarded, and a nop is executed instead making it a two-cycle instruction. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here incfsz cnt, 1, 0 nzero : zero : before instruction pc = address (here) after instruction cnt = cnt + 1 if cnt = 0; pc = address(zero) if cnt 1 0; pc = address(nzero) infsnz increment f, skip if not 0 syntax: [ label ] infsnz f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) + 1 ? dest, skip if result 1 0 status affected: none encoding: 0100 10da ffff ffff description: the contents of register 'f' are incremented. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if the result is not 0, the next instruction, which is already fetched, is discarded, and a nop is executed instead making it a two- cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here infsnz reg, 1, 0 zero nzero before instruction pc = address (here) after instruction reg = reg + 1 if reg 1 0; pc = address (nzero) if reg = 0; pc = address (zero)
pic18cxx2 ds39026b-page 214 preliminary ? 7/99 microchip technology inc. iorlw inclusive or literal with wreg syntax: [ label ] iorlw k operands: 0 k 255 operation: (wreg) .or. k ? wreg status affected: n,z encoding: 0000 1001 kkkk kkkk description: the contents of wreg are ored with the eight bit literal 'k'. the result is placed in wreg. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write to wreg example : iorlw 0x35 before instruction wreg = 0x9a after instruction wreg = 0xbf iorwf inclusive or wreg with f syntax: [ label ] iorwf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (wreg) .or. (f) ? dest status affected: n,z encoding: 0001 00da ffff ffff description: inclusive or wreg with register 'f'. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : iorwf result, 0, 1 before instruction result = 0x13 wreg = 0x91 after instruction result = 0x13 wreg = 0x93
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 215 lfsr load fsr syntax: [ label ] lfsr f,k operands: 0 f 2 0 k 4095 operation: k ? fsrf status affected: none encoding: 1110 1111 1110 0000 00ff k 7 kkk k 11 kkk kkkk description: the 12-bit literal 'k' is loaded into the file select register pointed to by 'f' words: 2 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal 'k' msb process data write literal 'k' msb to fsrfh decode read literal 'k' lsb process data write literal 'k' to fsrfl example : lfsr 2, 0x3ab after instruction fsr2h = 0x03 fsr2l = 0xab movf move f syntax: [ label ] movf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: f ? dest status affected: n,z encoding: 0101 00da ffff ffff description: the contents of register 'f' is moved to a destination dependent upon the status of d. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). location 'f' can be any- where in the 256 byte bank. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write wreg example : movf reg, 0, 0 before instruction reg = 0x22 wreg = 0xff after instruction reg = 0x22 wreg = 0x22
pic18cxx2 ds39026b-page 216 preliminary ? 7/99 microchip technology inc. movff move f to f syntax: [ label ] movff f s ,f d operands: 0 f s 4095 0 f d 4095 operation: (f s ) ? f d status affected: none encoding: 1st word (source) 2nd word (destin.) 1100 1111 ffff ffff ffff ffff fff f s fff f d description: the contents of source register 'f s ' are moved to destination register 'f d '. location of source 'f s ' can be anywhere in the 4096 byte data space (000h to fffh), and location of destination 'f d ' can also be any- where from 000h to fffh. either source or destination can be wreg (a useful special situation). movff is particularly useful for transferring a data memory location to a peripheral register (such as the transmit buffer or an i/o port). the movff instruction cannot use the pcl, tosu, tosh or tosl as the destination register words: 2 cycles: 2 (3) q cycle activity: q1 q2 q3 q4 decode read register 'f' (src) process data no operation decode no operation no dummy read no operation write register 'f' (dest) example : movff reg1, reg2 before instruction reg1 = 0x33 reg2 = 0x11 after instruction reg1 = 0x33, reg2 = 0x33 movlb move literal to low nibble in bsr syntax: [ label ] movlb k operands: 0 k 255 operation: k ? bsr status affected: none encoding: 0000 0001 kkkk kkkk description: the 8-bit literal 'k' is loaded into the bank select register (bsr). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write literal 'k' to bsr example : movlb 5 before instruction bsr register= 0x02 after instruction bsr register= 0x05
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 217 movlw move literal to wreg syntax: [ label ] movlw k operands: 0 k 255 operation: k ? wreg status affected: none encoding: 0000 1110 kkkk kkkk description: the eight bit literal 'k' is loaded into wreg. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write to wreg example : movlw 0x5a after instruction wreg = 0x5a movwf move wreg to f syntax: [ label ] movwf f,a operands: 0 f 255 a ? [0,1] operation: (wreg) ? f status affected: none encoding: 0110 111a ffff ffff description: move data from wreg to register 'f'. location 'f' can be anywhere in the 256 byte bank. if a is 0, the access bank will be selected, over- riding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : movwf reg, 0 before instruction wreg = 0x4f reg = 0xff after instruction wreg = 0x4f reg = 0x4f
pic18cxx2 ds39026b-page 218 preliminary ? 7/99 microchip technology inc. mullw multiply literal with wreg syntax: [ label ] mullw k operands: 0 k 255 operation: (wreg) x k ? prodh:prodl status affected: none encoding: 0000 1101 kkkk kkkk description: an unsigned multiplication is car- ried out between the contents of wreg and the 8-bit literal 'k'. the 16-bit result is placed in prodh:prodl register pair. prodh contains the high byte. wreg is unchanged. none of the status flags are affected. note that neither overflow nor carry is possible in this opera- tion. a zero result is possible but not detected. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write registers prodh: prodl example : mullw 0xc4 before instruction wreg = 0xe2 prodh = ? prodl = ? after instruction wreg = 0xe2 prodh = 0xad prodl = 0x08 mulwf multiply wreg with f syntax: [ label ] mulwf f,a operands: 0 f 255 a ? [0,1] operation: (wreg) x (f) ? prodh:prodl status affected: none encoding: 0000 001a ffff ffff description: an unsigned multiplication is car- ried out between the contents of wreg and the register file loca- tion 'f'. the 16-bit result is stored in the prodh:prodl register pair. prodh contains the high byte. both wreg and 'f' are unchanged. none of the status flags are affected. note that neither overflow nor carry is possible in this opera- tion. a zero result is possible but not detected. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write registers prodh: prodl example : mulwf reg, 1 before instruction wreg = 0xc4 reg = 0xb5 prodh = ? prodl = ? after instruction wreg = 0xc4 reg = 0xb5 prodh = 0x8a prodl = 0x94
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 219 negf negate f syntax: [ label ] negf f,a operands: 0 f 255 a ? [0,1] operation: ( f ) + 1 ? f status affected: n,ov, c, dc, z encoding: 0110 110a ffff ffff description: location f is negated using twos complement. the result is placed in the data memory location 'f'. if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : negf reg, 1 before instruction reg = 0011 1010 [0x3a] after instruction reg = 1100 0110 [0xc6] nop no operation syntax: [ label ] nop operands: none operation: no operation status affected: none encoding: 0000 1111 0000 xxxx 0000 xxxx 0000 xxxx description: no operation. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation no operation no operation example : none.
pic18cxx2 ds39026b-page 220 preliminary ? 7/99 microchip technology inc. pop pop top of return stack syntax: [ label ] pop operands: none operation: (tos) ? bit bucket status affected: none encoding: 0000 0000 0000 0110 description: the tos value is pulled off the return stack and is discarded. the tos value then becomes the previ- ous value that was pushed onto the return stack. this instruction is provided to enable the user to properly manage the return stack to incorporate a software stack. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation pop tos value no operation example : pop goto new before instruction tos = 0031a2h stack (1 level down)= 014332h after instruction tos = 014332h pc = new push push top of return stack syntax: [ label ] push operands: none operation: (pc+2) ? tos status affected: none encoding: 0000 0000 0000 0101 description: the pc+2 is pushed onto the top of the return stack. the previous tos value is pushed down on the stack. this instruction allows to implement a software stack by modifying tos, and then push it onto the return stack. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode push pc+2 onto return stack no operation no operation example : push before instruction tos = 00345ah pc = 000124h after instruction pc = 000126h tos = 000126h stack (1 level down)= 00345ah
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 221 rcall relative call syntax: [ label ] rcall n operands: -1024 n 1023 operation: (pc) + 2 ? tos, (pc) + 2 + 2n ? pc status affected: none encoding: 1101 1nnn nnnn nnnn description: subroutine call with a jump up to 1k from the current location. first, return address (pc+2) is pushed onto the stack. then, add the 2s complement number 2n to the pc. since the pc will have incremented to fetch the next instruction, the new address will be pc+2+2n. this instruction is a two-cycle instruction. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal 'n' push pc to stack process data write to pc no operation no operation no operation no operation example : here rcall jump before instruction pc = address(here) after instruction pc = address(jump) tos = address (here+2) reset reset syntax: [ label ] reset operands: none operation: reset all registers and flags that are affected by a mclr reset. status affected: all encoding: 0000 0000 1111 1111 description: this instruction provides a way to execute a mclr reset in software. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode start reset no operation no operation example : reset after instruction registers= reset value flags* = reset value
pic18cxx2 ds39026b-page 222 preliminary ? 7/99 microchip technology inc. retfie return from interrupt syntax: [ label ] retfie s operands: s ? [0,1] operation: (tos) ? pc, 1 ? gie/gieh or peie/giel, if s = 1 (ws) ? wreg, (statuss) ? status, (bsrs) ? bsr, pclatu, pclath are unchanged. status affected: gie/gieh,peie/giel. encoding: 0000 0000 0001 000s description: return from interrupt. stack is popped and top of stack (tos) is loaded into the pc. interrupts are enabled by setting the either the high or low priority global inter- rupt enable bit. if s = 1, the con- tents of the shadow registers ws, statuss and bsrs are loaded into their corresponding registers, wreg, status and bsr. if s = 0, no update of these registers occurs (default). words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation no operation pop pc from stack set gieh or giel no operation no operation no operation no operation example : retfie 1 after interrupt pc = tos w=ws bsr = bsrs status = statuss gie/gieh, peie/giel= 1 retlw return literal to wreg syntax: [ label ] retlw k operands: 0 k 255 operation: k ? wreg, (tos) ? pc, pclatu, pclath are unchanged status affected: none encoding: 0000 1100 kkkk kkkk description: wreg is loaded with the eight bit literal 'k'. the program counter is loaded from the top of the stack (the return address). the high address latch (pclath) remains unchanged. words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data pop pc from stack, write to wreg no operation no operation no operation no operation example : call table ; wreg contains table ; offset value ; wreg now has ; table value : table addwf pcl ; wreg = offset retlw k0 ; begin table retlw k1 ; : : retlw kn ; end of table before instruction wreg = 0x07 after instruction wreg = value of kn
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 223 return return from subroutine syntax: [ label ] return s operands: s ? [0,1] operation: (tos) ? pc, if s = 1 (ws) ? wreg, (statuss) ? status, (bsrs) ? bsr, pclatu, pclath are unchanged status affected: none encoding: 0000 0000 0001 001s description: return from subroutine. the stack is popped and the top of the stack (tos) is loaded into the program counter. if s = 1, the contents of the shadow registers ws, statuss and bsrs are loaded into their corresponding registers, wreg, status and bsr. if s = 0, no update of these registers occurs (default). words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation process data pop pc from stack no operation no operation no operation no operation example : return after interrupt pc = tos rlcf rotate left f through carry syntax: [ label ] rlcf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) ? dest, (f<7>) ? c, (c) ? dest<0> status affected: c,n,z encoding: 0011 01da ffff ffff description: the contents of register 'f' are rotated one bit to the left through the carry flag. if 'd' is 0 the result is placed in wreg. if 'd' is 1 the result is stored back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a = 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : rlcf reg, 0, 0 before instruction reg = 1110 0110 c=0 after instruction reg = 1110 0110 wreg = 1100 1100 c=1 c register f
pic18cxx2 ds39026b-page 224 preliminary ? 7/99 microchip technology inc. rlncf rotate left f (no carry) syntax: [ label ] rlncf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) ? dest, (f<7>) ? dest<0> status affected: n,z encoding: 0100 01da ffff ffff description: the contents of register 'f' are rotated one bit to the left. if 'd' is 0 the result is placed in wreg. if 'd' is 1, the result is stored back in reg- ister 'f' (default). if a is 0, the access bank will be selected, over- riding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : rlncf reg, 1, 0 before instruction reg = 1010 1011 after instruction reg = 0101 0111 register f rrcf rotate right f through carry syntax: [ label ] rrcf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) ? dest, (f<0>) ? c, (c) ? dest<7> status affected: c,n,z encoding: 0011 00da ffff ffff description: the contents of register 'f' are rotated one bit to the right through the carry flag. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : rrcf reg, 0, 0 before instruction reg = 1110 0110 c=0 after instruction reg = 1110 0110 wreg = 0111 0011 c=0 c register f
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 225 rrncf rotate right f (no carry) syntax: [ label ] rrncf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) ? dest, (f<0>) ? dest<7> status affected: n,z encoding: 0100 00da ffff ffff description: the contents of register 'f' are rotated one bit to the right. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed back in register 'f' (default). if a is 0, the access bank will be selected, over- riding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example 1 : rrncf reg, 1, 0 before instruction reg = 1101 0111 after instruction reg = 1110 1011 example 2 : rrncf reg, 0, 0 before instruction wreg = ? reg = 1101 0111 after instruction wreg = 1110 1011 reg = 1101 0111 register f setf set f syntax: [ label ] setf f,a operands: 0 f 255 a ? [0,1] operation: ffh ? f status affected: none encoding: 0110 100a ffff ffff description: the contents of the specified regis- ter are set to ffh. if a is 0, the access bank will be selected, over- riding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write register 'f' example : setf reg,1 before instruction reg = 0x5a after instruction reg = 0xff
pic18cxx2 ds39026b-page 226 preliminary ? 7/99 microchip technology inc. sleep enter sleep mode syntax: [ label ] sleep operands: none operation: 00h ? wdt, 0 ? wdt postscaler, 1 ? to , 0 ? pd status affected: to , pd encoding: 0000 0000 0000 0011 description: the power-down status bit (pd ) is cleared. the time-out status bit (to ) is set. watchdog timer and its postscaler are cleared. the processor is put into sleep mode with the oscillator stopped. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode no operation process data go to sleep example : sleep before instruction to =? pd =? after instruction to = 1 ? pd =0 ? if wdt causes wake-up, this bit is cleared subfwb subtract f from wreg with borrow syntax: [ label ] subfwb f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (wreg) C (f) C (c ) ? dest status affected: n,ov, c, dc, z encoding: 0101 01da ffff ffff description: subtract register 'f' and carry flag (borrow) from wreg (2s comple- ment method). if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored in register 'f' (default) . if a is 0, the access bank will be selected, overriding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 227 subfwb example 1 : subfwb reg, 1, 0 before instruction reg = 3 wreg = 2 c=1 after instruction reg = ff wreg = 2 c=0 z=0 n = 1 ; result is negative example 2 : subfwb reg, 0, 0 before instruction reg = 2 wreg = 5 c=1 after instruction reg = 2 wreg = 3 c=1 z=0 n = 0 ; result is positive example 3 : subfwb reg, 1, 0 before instruction reg = 1 wreg = 2 c=0 after instruction reg = 0 wreg = 2 c=1 z = 1 ; result is zero n=0 sublw subtract wreg from literal syntax: [ label ] sublw k operands: 0 k 255 operation: k C (wreg) ? wreg status affected: n,ov, c, dc, z encoding: 0000 1000 kkkk kkkk description: wreg is subtracted from the eight bit literal 'k'. the result is placed in wreg. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write to wreg example 1: sublw 0x02 before instruction wreg = 1 c=? after instruction wreg = 1 c = 1 ; result is positive z=0 n=0 example 2 : sublw 0x02 before instruction wreg = 2 c=? after instruction wreg = 0 c = 1 ; result is zero z=1 n=0 example 3 : sublw 0x02 before instruction wreg = 3 c=? after instruction wreg = ff ; (2s complement) c = 0 ; result is negative z=0 n=1
pic18cxx2 ds39026b-page 228 preliminary ? 7/99 microchip technology inc. subwf subtract wreg from f syntax: [ label ] subwf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) C (wreg) ? dest status affected: n,ov, c, dc, z encoding: 0101 11da ffff ffff description: subtract wreg from register 'f' (2s complement method). if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored back in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination subwf subtract wreg from f (contd) example 1 : subwf reg, 1, 0 before instruction reg = 3 wreg = 2 c=? after instruction reg = 1 wreg = 2 c = 1 ; result is positive z=0 n=0 example 2 : subwf reg, 0, 0 before instruction reg = 2 wreg = 2 c=? after instruction reg = 2 wreg = 0 c = 1 ; result is zero z=1 n=0 example 3 : subwf reg, 1, 0 before instruction reg = 1 wreg = 2 c=? after instruction reg = ffh ; (2s complement) wreg = 2 c = 0 ; result is negative z=0 n=1
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 229 subwfb subtract wreg from f with borrow syntax: [ label ] subwfb f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f) C (wreg) C (c ) ? dest status affected: n,ov, c, dc, z encoding: 0101 10da ffff ffff description: subtract wreg and the carry flag (borrow) from register 'f' (2s com- plement method). if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored back in reg- ister 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination subwfb subtract wreg from f with borrow (contd) example 1 : subwfb reg, 1, 0 before instruction reg = 0x19 (0001 1001) wreg = 0x0d (0000 1101) c=1 after instruction reg = 0x0c (0000 1011) wreg = 0x0d (0000 1101) c=1 z=0 n = 0 ; result is positive example2 : subwfbreg, 0, 0 before instruction reg = 0x1b (0001 1011) wreg = 0x1a (0001 1010) c=0 after instruction reg = 0x1b (0001 1011) wreg = 0x00 c=1 z = 1 ; result is zero n=0 example3 : subwfbreg, 1, 0 before instruction reg = 0x03 (0000 0011) wreg = 0x0e (0000 1101) c=1 after instruction reg = 0xf5 (1111 0100 ) [2s comp] wreg = 0x0e (0000 1101) c=0 z=0 n = 1 ; result is negative
pic18cxx2 ds39026b-page 230 preliminary ? 7/99 microchip technology inc. swapf swap f syntax: [ label ] swapf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (f<3:0>) ? dest<7:4>, (f<7:4>) ? dest<3:0> status affected: none encoding: 0011 10da ffff ffff description: the upper and lower nibbles of reg- ister 'f' are exchanged. if 'd' is 0, the result is placed in wreg. if 'd' is 1, the result is placed in register 'f' (default). if a is 0, the access bank will be selected, overriding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : swapf reg, 1, 0 before instruction reg = 0x53 after instruction reg = 0x35
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 231 tblrd table read syntax: [ label ] tblrd ( *; *+; *-; +*) operands: none operation: if tblrd *, (prog mem (tblptr)) ? tablat; tblptr - no change; if tblrd *+, (prog mem (tblptr)) ? tablat; (tblptr) +1 ? tblptr; if tblrd *-, (prog mem (tblptr)) ? tablat; (tblptr) -1 ? tblptr; if tblrd +*, (tblptr) +1 ? tblptr; (prog mem (tblptr)) ? tablat; status affected: none encoding: 0000 0000 0000 10nn nn=0 * =1 *+ =2 *- =3 +* description: this instruction is used to read the contents of program memory (p.m.). to address the program memory a pointer called table pointer (tblptr) is used. the tblptr (a 21-bit pointer) points to each byte in the program memory. tblptr has a 2 mbyte address range. tblptr[0] = 0:least significant byte of program memory word tblptr[0] = 1:most significant byte of program memory word the tblrd instruction can modify the value of tblptr as follows: ? no change ? post-increment ? post-decrement ? pre-increment words: 1 cycles: 2 q cycle activity: q1 q2 q3 q4 decode no operation no operation no operation no operation no operation (read program memory) no operation no operation (write ta b l at ) tblrd table read (contd) example1 : tblrd *+ ; before instruction tablat = 0x55 tblptr = 0x00a356 memory(0x00a356) = 0x34 after instruction tablat = 0x34 tblptr = 0x00a357 example2 : tblrd +* ; before instruction tablat = 0xaa tblptr = 0x01a357 memory(0x01a357) = 0x12 memory(0x01a358) = 0x34 after instruction tablat = 0x34 tblptr = 0x01a358
pic18cxx2 ds39026b-page 232 preliminary ? 7/99 microchip technology inc. tblwt table write syntax: [ label ] tblwt ( *; *+; *-; +*) operands: none operation: if tblwt*, (tablat) ? prog mem (tblptr) or holding register; tblptr - no change; if tblwt*+, (tablat) ? prog mem (tblptr) or holding register; (tblptr) +1 ? tblptr; if tblwt*-, (tablat) ? prog mem (tblptr) or holding register; (tblptr) -1 ? tblptr; if tblwt+*, (tblptr) +1 ? tblptr; (tablat) ? prog mem (tblptr) or holding register; status affected: none encoding: 0000 0000 0000 11nn nn=0 * =1 *+ =2 *- =3 +* description: this instruction is used to program the contents of program memory (p.m.). the tblptr (a 21-bit pointer) points to each byte in the program memory. tblptr has a 2 mbtye address range. the lsb of the tblptr selects which byte of the program memory location to access. tblptr[0] = 0:least significant byte of program memory word tblptr[0] = 1:most significant byte of program memory word the tblwt instruction can modify the value of tblptr as follows: ? no change ? post-increment ? post-decrement ? pre-increment words: 1 cycles: 2 (many if long write is to on-chip eprom program memory) q cycle activity: q1 q2 q3 q4 decode no operation no operation no operation no operation no operation (read ta b l at ) no operation no operation (write to holding register or memory) tblwt table write (c ont.d) example1 : tblwt *+; before instruction tablat = 0x55 tblptr = 0x00a356 memory(0x00a356) = 0xff after instructions (table write completion) tablat = 0x55 tblptr = 0x00a357 memory(0x00a356) = 0x55 example 2 : tblwt +*; before instruction tablat = 0x34 tblptr = 0x01389a memory(0x01389a) = 0xff memory(0x01389b) = 0xff after instruction (table write completion) tablat = 0x34 tblptr = 0x01389b memory(0x01389a) = 0xff memory(0x01389b) = 0x34
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 233 tstfsz test f, skip if 0 syntax: [ label ] tstfsz f,a operands: 0 f 255 a ? [0,1] operation: skip if f = 0 status affected: none encoding: 0110 011a ffff ffff description: if 'f' = 0, the next instruction, fetched during the current instruc- tion execution, is discarded and a nop is executed making this a two- cycle instruction. if a is 0, the access bank will be selected, over- riding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1(2) note: 3 cycles if skip and followed by a 2-word instruction q cycle activity: q1 q2 q3 q4 decode read register 'f' process data no operation if skip: q1 q2 q3 q4 no operation no operation no operation no operation if skip and followed by 2-word instruction: q1 q2 q3 q4 no operation no operation no operation no operation no operation no operation no operation no operation example : here tstfsz cnt, 1 nzero : zero : before instruction pc = address(here) after instruction if cnt = 0x00, pc = address (zero) if cnt 1 0x00, pc = address (nzero) xorlw exclusive or literal with wreg syntax: [ label ] xorlw k operands: 0 k 255 operation: (wreg) .xor. k ? wreg status affected: n,z encoding: 0000 1010 kkkk kkkk description: the contents of wreg are xored with the 8-bit literal 'k'. the result is placed in wreg. words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read literal 'k' process data write to wreg example :xorlw0xaf before instruction wreg = 0xb5 after instruction wreg = 0x1a
pic18cxx2 ds39026b-page 234 preliminary ? 7/99 microchip technology inc. xorwf exclusive or wreg with f syntax: [ label ] xorwf f,d,a operands: 0 f 255 d ? [0,1] a ? [0,1] operation: (wreg) .xor. (f) ? dest status affected: n,z encoding: 0001 10da ffff ffff description: exclusive or the contents of wreg with register 'f'. if 'd' is 0, the result is stored in wreg. if 'd' is 1, the result is stored back in the reg- ister 'f' (default). if a is 0, the access bank will be selected, over- riding the bsr value. if a is 1, then the bank will be selected as per the bsr value (default). words: 1 cycles: 1 q cycle activity: q1 q2 q3 q4 decode read register 'f' process data write to destination example : xorwf reg, 1, 0 before instruction reg = 0xaf wreg = 0xb5 after instruction reg = 0x1a wreg = 0xb5
? 1999 microchip technology inc. preliminary ds39026b-page 235 pic18cxx2 20.0 development support the picmicro ? microcontrollers are supported with a full range of hardware and software development tools: ? integrated development environment - mplab? ide software ? assemblers/compilers/linkers - mpasm assembler - mplab-c17 and mplab-c18 c compilers - mplink/mplib linker/librarian ? simulators - mplab-sim software simulator ?emulators - mplab-ice real-time in-circuit emulator - picmaster ? /picmaster-ce in-circuit emulator - icepic? ? in-circuit debugger - mplab-icd for pic16f877 ? device programmers -pro mate a ii universal programmer - picstart a plus entry-level prototype programmer ? low-cost demonstration boards - simice - picdem-1 - picdem-2 - picdem-3 - picdem-17 - seeval a -k ee l oq a 20.1 mplab integrated development environment software - the mplab ide software brings an ease of software development previously unseen in the 8-bit microcontroller market. mplab is a windows a -based application which contains: ? multiple functionality -editor - simulator - programmer (sold separately) - emulator (sold separately) ? a full featured editor ? a project manager ? customizable tool bar and key mapping ? a status bar ? on-line help mplab allows you to: ? edit your source files (either assembly or c) ? one touch assemble (or compile) and download to picmicro tools (automatically updates all project information) ? debug using: - source files - absolute listing file - object code the ability to use mplab with microchips simulator, mplab-sim, allows a consistent platform and the abil- ity to easily switch from the cost-effective simulator to the full featured emulator with minimal retraining. 20.2 mpasm assembler mpasm is a full featured universal macro assembler for all picmicro mcus. it can produce absolute code directly in the form of hex files for device program- mers, or it can generate relocatable objects for mplink. mpasm has a command line interface and a windows shell and can be used as a standalone application on a windows 3.x or greater system. mpasm generates relocatable object files, intel standard hex files, map files to detail memory usage and symbol reference, an absolute lst file which contains source lines and gen- erated machine code, and a cod file for mplab debugging. mpasm features include: ? mpasm and mplink are integrated into mplab projects. ? mpasm allows user defined macros to be created for streamlined assembly. ? mpasm allows conditional assembly for multi pur- pose source files. ? mpasm directives allow complete control over the assembly process. 20.3 mplab-c17 and mplab-c18 c compilers the mplab-c17 and mplab-c18 code development systems are complete ansi c compilers and inte- grated development environments for microchips pic17cxxx and pic18cxxx family of microcontrol- lers, respectively. these compilers provide powerful integration capabilities and ease of use not found with other compilers. for easier source level debugging, the compilers pro- vide symbol information that is compatible with the mplab ide memory display.
pic18cxx2 ds39026b-page 236 preliminary ? 1999 microchip technology inc. 20.4 mplink/mplib linker/librarian mplink is a relocatable linker for mpasm and mplab-c17 and mplab-c18. it can link relocatable objects from assembly or c source files along with pre- compiled libraries using directives from a linker script. mplib is a librarian for pre-compiled code to be used with mplink. when a routine from a library is called from another source file, only the modules that contains that routine will be linked in with the application. this allows large libraries to be used efficiently in many dif- ferent applications. mplib manages the creation and modification of library files. mplink features include: ? mplink works with mpasm and mplab-c17 and mplab-c18. ? mplink allows all memory areas to be defined as sections to provide link-time flexibility. mplib features include: ? mplib makes linking easier because single librar- ies can be included instead of many smaller files. ? mplib helps keep code maintainable by grouping related modules together. ? mplib commands allow libraries to be created and modules to be added, listed, replaced, deleted, or extracted. 20.5 mplab-sim software simulator the mplab-sim software simulator allows code development in a pc host environment by simulating the picmicro series microcontrollers on an instruction level. on any given instruction, the data areas can be examined or modified and stimuli can be applied from a file or user-defined key press to any of the pins. the execution can be performed in single step, execute until break, or trace mode. mplab-sim fully supports symbolic debugging using mplab-c17 and mplab-c18 and mpasm. the soft- ware simulator offers the flexibility to develop and debug code outside of the laboratory environment mak- ing it an excellent multi-project software development tool. 20.6 mplab-ice high performance universal in-circuit emulator with mplab ide the mplab-ice universal in-circuit emulator is intended to provide the product development engineer with a complete microcontroller design tool set for picmicro microcontrollers (mcus). software control of mplab-ice is provided by the mplab integrated development environment (ide), which allows editing, make and download, and source debugging from a single environment. interchangeable processor modules allow the system to be easily reconfigured for emulation of different pro- cessors. the universal architecture of the mplab-ice allows expansion to support new picmicro microcon- trollers. the mplab-ice emulator system has been designed as a real-time emulation system with advanced fea- tures that are generally found on more expensive devel- opment tools. the pc platform and microsoft ? windows 3.x/95/98 environment were chosen to best make these features available to you, the end user. mplab-ice 2000 is a full-featured emulator system with enhanced trace, trigger, and data monitoring fea- tures. both systems use the same processor modules and will operate across the full operating speed range of the picmicro mcu. 20.7 picmaster/picmaster ce the picmaster system from microchip technology is a full-featured, professional quality emulator system. this flexible in-circuit emulator provides a high-quality, universal platform for emulating microchip 8-bit picmicro microcontrollers (mcus). picmaster sys- tems are sold worldwide, with a ce compliant model available for european union (eu) countries. 20.8 icepic icepic is a low-cost in-circuit emulation solution for the microchip technology pic16c5x, pic16c6x, pic16c7x, and pic16cxxx families of 8-bit one-time- programmable (otp) microcontrollers. the modular system can support different subsets of pic16c5x or pic16cxxx products through the use of interchangeable personality modules or daughter boards. the emulator is capable of emulating without target application circuitry being present. 20.9 mplab-icd in-circuit debugger microchip's in-circuit debugger, mplab-icd, is a pow- erful, low-cost run-time development tool. this tool is based on the flash pic16f877 and can be used to develop for this and other picmicro microcontrollers from the pic16cxxx family. mplab-icd utilizes the in-circuit debugging capability built into the pic16f87x. this feature, along with microchip's in-cir- cuit serial programming protocol, offers cost-effective in-circuit flash programming and debugging from the graphical user interface of the mplab integrated development environment. this enables a designer to develop and debug source code by watching variables, single-stepping and setting break points. running at full speed enables testing hardware in real-time. the mplab-icd is also a programmer for the flash pic16f87x family.
? 1999 microchip technology inc. preliminary ds39026b-page 237 pic18cxx2 20.10 pro mate ii universal programmer the pro mate ii universal programmer is a full-fea- tured programmer capable of operating in stand-alone mode as well as pc-hosted mode. pro mate ii is ce compliant. the pro mate ii has programmable v dd and v pp supplies which allows it to verify programmed memory at v dd min and v dd max for maximum reliability. it has an lcd display for instructions and error messages, keys to enter commands and a modular detachable socket assembly to support various package types. in stand-alone mode the pro mate ii can read, verify or program picmicro devices. it can also set code-protect bits in this mode. 20.11 picstart plus entry level development system the picstart programmer is an easy-to-use, low- cost prototype programmer. it connects to the pc via one of the com (rs-232) ports. mplab integrated development environment software makes using the programmer simple and efficient. picstart plus supports all picmicro devices with up to 40 pins. larger pin count devices such as the pic16c92x, and pic17c76x may be supported with an adapter socket. picstart plus is ce compliant. 20.12 simice entry-level hardware simulator simice is an entry-level hardware development sys- tem designed to operate in a pc-based environment with microchips simulator mplab-sim. both simice and mplab-sim run under microchip technologys mplab integrated development environment (ide) software. specifically, simice provides hardware sim- ulation for microchips pic12c5xx, pic12ce5xx, and pic16c5x families of picmicro 8-bit microcontrollers. simice works in conjunction with mplab-sim to pro- vide non-real-time i/o port emulation. simice enables a developer to run simulator code for driving the target system. in addition, the target system can provide input to the simulator code. this capability allows for simple and interactive debugging without having to manually generate mplab-sim stimulus files. simice is a valu- able debugging tool for entry-level system develop- ment. 20.13 picdem-1 low-cost picmicro demonstration board the picdem-1 is a simple board which demonstrates the capabilities of several of microchips microcontrol- lers. the microcontrollers supported are: pic16c5x (pic16c54 to pic16c58a), pic16c61, pic16c62x, pic16c71, pic16c8x, pic17c42, pic17c43 and pic17c44. all necessary hardware and software is included to run basic demo programs. the users can program the sample microcontrollers provided with the picdem-1 board, on a pro mate ii or picstart-plus programmer, and easily test firm- ware. the user can also connect the picdem-1 board to the mplab-ice emulator and download the firmware to the emulator for testing. additional proto- type area is available for the user to build some addi- tional hardware and connect it to the microcontroller socket(s). some of the features include an rs-232 interface, a potentiometer for simulated analog input, push-button switches and eight leds connected to portb. 20.14 picdem-2 low-cost pic16cxx demonstration board the picdem-2 is a simple demonstration board that supports the pic16c62, pic16c64, pic16c65, pic16c73 and pic16c74 microcontrollers. all the necessary hardware and software is included to run the basic demonstration programs. the user can program the sample microcontrollers provided with the picdem-2 board, on a pro mate ii pro- grammer or picstart-plus, and easily test firmware. the mplab-ice emulator may also be used with the picdem-2 board to test firmware. additional prototype area has been provided to the user for adding addi- tional hardware and connecting it to the microcontroller socket(s). some of the features include a rs-232 inter- face, push-button switches, a potentiometer for simu- lated analog input, a serial eeprom to demonstrate usage of the i 2 c bus and separate headers for connec- tion to an lcd module and a keypad. 20.15 picdem-3 low-cost pic16cxxx demonstration board the picdem-3 is a simple demonstration board that supports the pic16c923 and pic16c924 in the plcc package. it will also support future 44-pin plcc microcontrollers with a lcd module. all the neces- sary hardware and software is included to run the basic demonstration programs. the user can pro- gram the sample microcontrollers provided with the picdem-3 board, on a pro mate ii program- mer or picstart plus with an adapter socket, and easily test firmware. the mplab-ice emulator may also be used with the picdem-3 board to test firm- ware. additional prototype area has been provided to the user for adding hardware and connecting it to the microcontroller socket(s). some of the features include an rs-232 interface, push-button switches, a potenti- ometer for simulated analog input, a thermistor and separate headers for connection to an external lcd module and a keypad. also provided on the picdem-3 board is an lcd panel, with 4 commons and 12 seg- ments, that is capable of displaying time, temperature and day of the week. the picdem-3 provides an addi- tional rs-232 interface and windows 3.1 software for showing the demultiplexed lcd signals on a pc. a sim- ple serial interface allows the user to construct a hard- ware demultiplexer for the lcd signals.
pic18cxx2 ds39026b-page 238 preliminary ? 1999 microchip technology inc. 20.16 picdem-17 the picdem-17 is an evaluation board that demon- strates the capabilities of several microchip microcon- trollers, including pic17c752, pic17c756, pic17c762, and pic17c766. all necessary hardware is included to run basic demo programs, which are sup- plied on a 3.5-inch disk. a programmed sample is included, and the user may erase it and program it with the other sample programs using the pro mate ii or picstart plus device programmers and easily debug and test the sample code. in addition, picdem-17 sup- ports down-loading of programs to and executing out of external flash memory on board. the picdem-17 is also usable with the mplab-ice or picmaster emu- lator, and all of the sample programs can be run and modified using either emulator. additionally, a gener- ous prototype area is available for user hardware. 20.17 seeval evaluation and programming system the seeval seeprom designers kit supports all microchip 2-wire and 3-wire serial eeproms. the kit includes everything necessary to read, write, erase or program special features of any microchip seeprom product including smart serials ? and secure serials. the total endurance ? disk is included to aid in trade- off analysis and reliability calculations. the total kit can significantly reduce time-to-market and result in an optimized system. 20.18 k ee l oq evaluation and programming tools k ee l oq evaluation and programming tools support microchips hcs secure data products. the hcs eval- uation kit includes an lcd display to show changing codes, a decoder to decode transmissions, and a pro- gramming interface to program test transmitters.
? 1999 microchip technology inc. preliminary ds39026b-page 239 pic18cxx2 table 20-1: development tools from microchip pic12cxxx pic14000 pic16c5x pic16c6x pic16cxxx pic16f62x pic16c7x pic16c7xx pic16c8x pic16f8xx pic16c9xx pic17c4x pic17c7xx pic18cxx2 24cxx/ 25cxx/ 93cxx hcsxxx mcrfxxx mcp2510 software tools mplab ? integrated development environment mplab ? c17 compiler mplab ? c18 compiler mpasm/mplink emulators mplab ?-ice ** picmaster/picmaster-ce icepic ? low-cost in-circuit emulator debugger mplab-icd in-circuit debugger * * programmers picstart a plus low-cost universal dev. kit ** pro mate a ii universal programmer ** demo boards and eval kits simice picdem-1 ? picdem-2 ? ? picdem-3 picdem-14a picdem-17 k ee l oq ? evaluation kit k ee l oq transponder kit microid ? programmers kit 125 khz microid developers kit 125 khz anticollision microid developers kit 13.56 mhz anticollision microid developers kit mcp2510 can developers kit * contact the microchip technology inc. web site at www.microchip.com for information on how to use the mplab-icd in-circuit deb ugger (dv164001) with pic16c62, 63, 64, 65, 72, 73, 74, 76, 77 ** contact microchip technology inc. for availability date. ? development tool is available on select devices.
pic18cxx2 ds39026b-page 240 preliminary ? 1999 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 241 21.0 electrical characteristics absolute maximum ratings (?) ambient temperature under bias................................................................................................. ........... .-55c to +125c storage temperature ............................................................................................................ .................. -65c to +150c voltage on any pin with respect to v ss (except v dd , mclr , and ra4).......................................... -0.3v to (v dd + 0.3v) voltage on v dd with respect to v ss ......................................................................................................... -0.3v to +7.5v voltage on mclr with respect to v ss (note 2).......................................................................................... 0v to +13.25v voltage on ra4 with respect to vss ............................................................................................. .................. 0v to +8.5v total power dissipation (note 1)............................................................................................... .................................1.0w maximum current out of v ss pin ........................................................................................................................... 300 ma maximum current into v dd pin ........................................................................................................................... ...250 ma input clamp current, i ik (v i < 0 or v i > v dd ) ...................................................................................................................... 20 ma output clamp current, i ok (v o < 0 or v o > v dd ) .............................................................................................................. 20 ma maximum output current sunk by any i/o pin..................................................................................... .....................25 ma maximum output current sourced by any i/o pin .................................................................................. ..................25 ma maximum current sunk by porta, portb, and porte (note 3) (combined)....................................................200 ma maximum current sourced by porta, portb, and porte (note 3) (combined) ..............................................200 ma maximum current sunk by portc and portd (note 3) (combined) ..................................................................200 ma maximum current sourced by portc and portd (note 3) (combined) .............................................................200 ma note 1: power dissipation is calculated as follows: pdis = v dd x {i dd - ? i oh } + ? {(v dd -v oh ) x i oh } + ? (v o l x i ol ) note 2: voltage spikes below v ss at the mclr /v pp pin, inducing currents greater than 80 ma, may cause latch-up. thus, a series resistor of 50-100 w should be used when applying a low level to the mclr /v pp pin, rather than pulling this pin directly to v ss . note 3: portd and porte not available on the pic18c2x2 devices. ? notice: stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. exposure to maximum rating conditions for extended periods may affect device reliability.
pic18cxx2 ds39026b-page 242 preliminary ? 7/99 microchip technology inc. figure 21-1: pic18cxx2 voltage-frequency graph (industrial) figure 21-2: pic18lcxx2 voltage-frequency graph (industrial) frequency voltage 6.0 v 5.5 v 4.5 v 4.0 v 2.0 v 40 mhz 5.0 v 3.5 v 3.0 v 2.5 v pic18cxxx 4.2v frequency voltag e 6.0 v 5.5 v 4.5 v 4.0 v 2.0 v 40 mhz 5.0 v 3.5 v 3.0 v 2.5 v pic18lcxxx f max = (20.0 mhz/v) (v ddappmin - 2.5 v) + 6 mhz note: v ddappmin is the minimum voltage of the picmicro ? device in the application 6 mhz 4.2v
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 243 21.1 dc characteristics: pic18cxx2 (industrial, extended) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. symbol characteristic min typ max units conditions v dd supply voltage d001 4.2 5.5 v d002 v dr ram data retention voltage (1) 1.5 v d003 v por v dd start voltage to ensure internal power- on reset signal 0.7 v see section on power-on reset for details d004 s vdd v dd rise rate to ensure internal power- on reset signal 0.05 v/ms see section on power-on reset for details v bor brown-out reset voltage d005 borv1:borv0 = 1x n.a. n.a. v not in operating voltage range of device borv1:borv0 = 01 4.2 4.46 v borv1:borv0 = 00 4.5 4.78 v d010 i dd supply current (2,4) tbdma xt, rc, rcio osc configurations f osc = 4 mhz, v dd = 4.2v d010a tbd m a lp osc configuration f osc = 32 khz, v dd = 4.2v d010c 45 ma ec, ecio osc configurations, fosc = 40 mhz, v dd = 5.5v d013 50 ma hs osc configurations fosc = 25 mhz, v dd = 5.5v d013 50 ma hs + pll osc configuration fosc = 10 mhz, v dd = 5.5v d014 tbd tbd m a m a oscb osc configuration f osc = 32 khz, v dd = 4.2v f osc = 32 khz, v dd = 4.2v, 25 c legend: shading of rows is to assist in readability of the table. note 1: this is the limit to which v dd can be lowered in sleep mode or during a device reset without losing ram data. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tristated, pulled to v dd mclr = v dd ; wdt enabled/disabled as specified. 3: the power-down current in sleep mode does not depend on the oscillator type. power-down current is mea- sured with the part in sleep mode, with all i/o pins in hi-impedance state and tied to v dd or v ss , and all fea- tures that add delta current disabled (such as wdt, timer1 oscillator, bor, ...). 4: for rc osc configuration, current through rext is not included. the current through the resistor can be esti- mated by the formula ir = v dd /2rext (ma) with rext in kohm.
pic18cxx2 ds39026b-page 244 preliminary ? 7/99 microchip technology inc. 21.1 dc characteristics: pic18cxx2 (industrial, extended) (contd) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. symbol characteristic min typ max units conditions i pd power-down current (3) d020 <1 tbd 36 m a m a v dd = 4.2v, -40 c to +85 c v dd = 5.5v, -40 c to +85 c d020a tbd m a v dd = 4.2v, 25 c d021b pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 245 21.2 d c characteristics: p ic18lcxx2 (industrial) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. symbol characteristic min typ max units conditions v dd supply voltage d001 2.5 5.5 v hs, xt, rc and lp osc mode d002 v dr ram data retention voltage (1) 1.5 v d003 v por v dd start voltage to ensure internal power- on reset signal 0.7 v see section on power-on reset for details d004 s vdd v dd rise rate to ensure internal power- on reset signal 0.05 v/ms see section on power-on reset for details v bor brown-out reset voltage d005 borv1:borv0 = 11 2.5 2.66 v borv1:borv0 = 10 2.7 2.86 v borv1:borv0 = 01 4.2 4.46 v borv1:borv0 = 00 4.5 4.78 v d010 i dd supply current (2,4) 4ma xt, rc, rcio osc configurations f osc = 4 mhz, v dd = 2.5v d010a 48 m a lp osc configuration f osc = 32 khz, v dd = 2.5v d010c 45 ma ec, ecio osc configurations, fosc = 40 mhz, v dd = 5.5v d013 tbd 50 ma ma hs osc configurations fosc = 6 mhz, v dd = 2.5v fosc = 25 mhz, v dd = 5.5v d013 50 ma hs + pll osc configuration fosc = 10 mhz, v dd = 5.5v d014 48 tbd m a m a timer1 osc configuration f osc = 32 khz, v dd = 2.5v f osc = 32 khz, v dd = 2.5v, 25 c legend: shading of rows is to assist in readability of the table. note 1: this is the limit to which v dd can be lowered in sleep mode or during a device reset without losing ram data. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tristated, pulled to v dd mclr = v dd ; wdt enabled/disabled as specified. 3: the power-down current in sleep mode does not depend on the oscillator type. power-down current is mea- sured with the part in sleep mode, with all i/o pins in hi-impedance state and tied to v dd or v ss , and all fea- tures that add delta current disabled (such as wdt, timer1 oscillator, bor, ...). 4: for rc osc configuration, current through rext is not included. the current through the resistor can be esti- mated by the formula ir = v dd /2rext (ma) with rext in kohm.
pic18cxx2 ds39026b-page 246 preliminary ? 7/99 microchip technology inc. 21.2 dc characteristics: pic18lcxx2 (industrial) (contd) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial param no. symbol characteristic min typ max units conditions d020 i pd power-down current (3) <2.5 5 36 tbd m a m a m a v dd = 2.5v, -40 c to +85 c v dd = 5.5v, -40 c to +85 c v dd = 2.5v, 25 c module differential current d022 d i wdt watchdog timer 12 25 tbd m a m a m a v dd = 2.5v v dd = 5.5v v dd = 2.5v, 25 c d022a d i bor brown-out reset 50 tbd m a m a v dd = 5.5v v dd = 2.5v, 25 c d022b d i lvd low voltage detect 50 tbd m a m a v dd = 2.5v v dd = 2.5v, 25 c d025 d i oscb timer1 oscillator 3 tbd m a m a v dd = 2.5v v dd = 2.5v, 25 c legend: shading of rows is to assist in readability of the table. note 1: this is the limit to which v dd can be lowered in sleep mode or during a device reset without losing ram data. 2: the supply current is mainly a function of the operating voltage and frequency. other factors, such as i/o pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. the test conditions for all i dd measurements in active operation mode are: osc1 = external square wave, from rail to rail; all i/o pins tristated, pulled to v dd mclr = v dd ; wdt enabled/disabled as specified. 3: the power-down current in sleep mode does not depend on the oscillator type. power-down current is measured with the part in sleep mode, with all i/o pins in hi-impedance state and tied to v dd and v ss , and all features that add delta current disabled (such as wdt, timer1 oscillator, bor, ...). 4: for rc osc configuration, current through rext is not included. the current through the resistor can be esti- mated by the formula ir = v dd /2rext (ma) with rext in kohm.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 247 21.3 dc characteristics: pic18cxx2 (industrial, extended ) and p ic18lcxx2 (industrial ) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -4 0c t a +85c for industrial -40c t a +125c for extended param no. symbol characteristic min max units conditions v il input low voltage i/o ports: d030 with ttl buffer v ss 0.15v dd vv dd < 4.5v d030a 0.8 v 4.5v v dd 5.5v d031 with schmitt trigger buffer rc3 and rc4 v ss v ss 0.2v dd 0.3v dd v v d032 mclr v ss 0.2v dd v d032a osc1 (in xt, hs and lp modes) and t1osi v ss 0.3v dd v d033 osc1(in rc mode) (1) v ss 0.2v dd v v ih input high voltage i/o ports: d040 with ttl buffer 0.25v dd + 0.8v v dd vv dd < 4.5v d040a 2.0 v dd v4.5v v dd 5.5v d041 with schmitt trigger buffer rc3 and rc4 0.8v dd 0.7v dd v dd v dd v v d042 mclr 0.8v dd v dd v d042a osc1 (in xt, hs and lp modes) and t1osi 0.7v dd v dd v d043 osc1 (rc mode) (1) 0.9v dd v dd v d050 v hys hysteresis of schmitt trigger inputs tbd tbd v i il input leakage current (2,3) d060 i/o ports 1 m av ss v pin v dd , pin at hi-impedance d061 mclr 5 m avss v pin v dd d063 osc1 5 m avss v pin v dd i pu weak pull-up current d070 i purb portb weak pull-up current 50 400 m av dd = 5v, v pin = v ss note 1: in rc oscillator configuration, the osc1/clkin pin is a schmitt trigger input. it is not recommended that the picmicro be driven with an external clock while in rc mode. 2: the leakage current on the mclr pin is strongly dependent on the applied voltage level. the specified levels represent normal operating conditions. higher leakage current may be measured at different input voltages. 3: negative current is defined as current sourced by the pin.
pic18cxx2 ds39026b-page 248 preliminary ? 7/99 microchip technology inc. 21.3 dc characteristics: pic18cxx2 (industrial, extended) and pic18lcxx2 (industrial) (contd) dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. symbol characteristic min max units conditions v ol output low voltage d080 i/o ports 0.6 v i ol = 8.5 ma, v dd = 4.5v, -40 c to +85 c d080a 0.6 v i ol = 7.0 ma, v dd = 4.5v, -40 c to +125 c d083 osc2/clkout (rc mode) 0.6vi ol = 1.6 ma, v dd = 4.5v, -40 c to +85 c d083a 0.6 v i ol = 1.2 ma, v dd = 4.5v, -40 c to +125 c v oh output high voltage (3) d090 i/o ports v dd - 0.7 v i oh = -3.0 ma, v dd = 4.5v, -40 c to +85 c d090a v dd - 0.7 v i oh = -2.5 ma, v dd = 4.5v, -40 c to +125 c d092 osc2/clkout (rc mode) v dd - 0.7 v i oh = -1.3 ma, v dd = 4.5v, -40 c to +85 c d092a v dd - 0.7 v i oh = -1.0 ma, v dd = 4.5v, -40 c to +125 c d150 v od open-drain high voltage 7.5 v ra4 pin capacitive loading specs on output pins d101 c io all i/o pins and osc2 (in rc mode) 50 pf to meet the ac timing specifications d102 c b scl, sda 400 pf in i 2 c mode note 1: in rc oscillator configuration, the osc1/clkin pin is a schmitt trigger input. it is not recommended that the picmicro be driven with an external clock while in rc mode. 2: the leakage current on the mclr pin is strongly dependent on the applied voltage level. the specified levels represent normal operating conditions. higher leakage current may be measured at different input voltages. 3: negative current is defined as current sourced by the pin.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 249 figure 21-3: low-voltage detect characteristics table 21-1: low voltage detect characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +85c for industrial -40c t a +125c for extended param no. symbol characteristic min max units conditions d420 v lvd lv d vo l t a g e lvv<3:0> = 0100 2.5 2.66 v lvv<3:0> = 0101 2.7 2.86 v lvv<3:0> = 0110 2.8 2.98 v lvv<3:0> = 0111 3.0 3.2 v lvv<3:0> = 1000 3.3 3.52 v lvv<3:0> = 1001 3.5 3.72 v lvv<3:0> = 1010 3.6 3.84 v lvv<3:0> = 1011 3.8 4.04 v lvv<3:0> = 1100 4.0 4.26 v lvv<3:0> = 1101 4.2 4.46 v lvv<3:0> = 1110 4.5 4.78 v v lvd lv d i f v dd (lvdif set by hardware) (lvdif can be cleared in software)
pic18cxx2 ds39026b-page 250 preliminary ? 7/99 microchip technology inc. table 21-2: eprom programming requirements dc characteristics standard operating conditions (unless otherwise stated) operating temperature -40c t a +40c param. no. sym characteristic min max units conditions internal program memory programming specs (note 1) d110 d111 d112 d113 d114 d115 v pp v ddp i pp i ddp t prog t erase voltage on mclr /v pp pin supply voltage during programming current into mclr /v pp pin supply current during programming programming pulse width eprom erase time device operation 3v device operation 3 3v 12.75 4.75 100 4 tbd 13.25 5.25 50 30 1000 v v ma ma m s hrs hrs note 2 terminated via internal/external interrupt or a reset note 1: these specifications are for the programming of the on-chip program memory eprom through the use of the table write instructions. the complete programming specifications can be found in: pic18cxxx program- ming specifications (literature number tbd). 2: the mclr /v pp pin may be kept in this range at times other than programming, but is not recommended.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 251 21.4 ac (timing) characteristics 21.4.1 timing parameter symbology the timing parameter symbols have been created fol- lowing one of the following formats: 1. tpps2pps 3. t cc : st (i 2 c specifications only) 2. tpps 4. ts (i 2 c specifications only) t ffrequency ttime lowercase letters (pp) and their meanings: pp cc ccp1 osc osc1 ck clkout rd rd cs cs rw rd or wr di sdi sc sck do sdo ss ss dt data in t0 t0cki io i/o port t1 t1cki mc mclr wr wr uppercase letters and their meanings: s ffall pperiod hhigh rrise i invalid (hi-impedance) v valid l low z hi-impedance i 2 c only aa output access high high buf bus free low low t cc : st (i 2 c specifications only) cc hd hold su setup st dat data input hold sto stop condition sta start condition
pic18cxx2 ds39026b-page 252 preliminary ? 7/99 microchip technology inc. 21.4.2 timing conditions the temperature and voltages specified in table 21-3 apply to all timing specifications unless otherwise noted. figure 21-4 specifies the load conditions for the timing specifications. table 21-3: temperature and voltage specifications - ac figure 21-4: load conditions for device timing specifications ac characteristics standard operating conditions (unless otherwise stated) operating temperature - 40c t a +85c for industrial -40c t a +125c for extended operating voltage v dd range as described in dc spec section 21.1 and section 21.2. lc parts operate for industrial temps only. v dd /2 c l r l pin pin v ss v ss c l r l =464 w c l = 50 pf for all pins except osc2/clkout and including d and e outputs as ports load condition 1 load condition 2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 253 21.4.3 timing diagrams and specifications figure 21-5: external clock timing table 21-4: external clock timing requirements param. no. symbol characteristic min max units conditions 1a fosc external clkin frequency (1) dc 40 mhz xt 0osc dc 40 mhz hs osc 4 10 mhz hs + pll osc dc dc 40 40 khz mhz lp osc ec oscillator frequency (1) dc 4 mhz rc osc 0.1 4 mhz xt osc 4 25 mhz hs osc 4 10 mhz hs + pll osc 5 200 khz lp osc mode 1tosc external clkin period (1) 250 ns xt and rc osc 40 ns hs osc 100 ns hs + pll osc 5 5 m s ns lp osc ec oscillator period (1) 250 ns rc osc 250 10,000 ns xt osc 100 40 10,000 100 ns ns hs osc hs + pll osc 5 m slp osc 2t cy instruction cycle time (1) 100 ns t cy = 4/f osc 3 tosl, to s h external clock in (osc1) high or low time 30 ns xt osc 2.5 m slp osc 10 ns hs osc 4tosr, to s f external clock in (osc1) rise or fall time 20 ns xt osc 50 ns lp osc 7.5 ns hs osc note 1: instruction cycle period (t cy ) equals four times the input oscillator time-base period. all specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. all devices are tested to operate at "min." values with an external clock applied to the osc1/clkin pin. when an external clock input is used, the "max." cycle time limit is "dc" (no clock) for all devices. osc1 clkout q4 q1 q2 q3 q4 q1 1 2 3 3 4 4
pic18cxx2 ds39026b-page 254 preliminary ? 7/99 microchip technology inc. table 21-5: pll clock timing specification (v dd = 4.2v - 5.5v) param no. symbol characteristic min max units conditions t rc pll start-up time (lock time) 2ms d clk clkout stability (jitter) using pll -2 +2 %
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 255 figure 21-6: clkout and i/o timing table 21-6: clkout and i/o timing requirements param. no. symbol characteristic min typ max units conditions 10 tosh2ckl osc1 - to clkout 75 200 ns (1) 11 tosh2ckh osc1 - to clkout - 75 200 ns (1) 12 tckr clkout rise time 35 100 ns (1) 13 tckf clkout fall time 35 100 ns (1) 14 tckl2iov clkout to port out valid 0.5t cy + 20 ns (1) 15 tiov2ckh port in valid before clkout - 0.25t cy + 25 ns (1) 16 tckh2ioi port in hold after clkout - 0ns (1) 17 tosh2iov osc1 - (q1 cycle) to port out valid 50 150 ns 18 tosh2ioi osc1 - (q2 cycle) to port input invalid (i/o in hold time) pic18 c xxx 100 ns 18a pic18 lc xxx 200 ns 19 tiov2osh port input valid to osc1 - (i/o in setup time) 0ns 20 tior port output rise time pic18 c xxx 10 25 ns 20a pic18 lc xxx 60 ns 21 tiof port output fall time pic18 c xxx 10 25 ns 21a pic18 lc xxx 60 ns 22?? t inp int pin high or low time t cy ns 23?? t rbp rb7:rb4 change int high or low time t cy ns 24?? t rcp rc7:rc4 change int high or low time 20 ns ??these parameters are asynchronous events not related to any internal clock edges. note 1: measurements are taken in rc mode where clkout output is 4 x t osc . note: refer to figure 21-4 for load conditions . osc1 clkout i/o pin (input) i/o pin (output) q4 q1 q2 q3 10 13 14 17 20, 21 19 18 15 11 12 16 old value new value
pic18cxx2 ds39026b-page 256 preliminary ? 7/99 microchip technology inc. figure 21-7: reset, watchdog timer, oscillator start-up timer and power-up timer timing figure 21-8: brown-out reset timing table 21-7: reset, watchdog timer, oscillator start-up timer, power-up timer and brown-out reset requirements param. no. symbol characteristic min typ max units conditions 30 tmcl mclr pulse width (low) 2 m s 31 t wdt watchdog timer time-out period (no prescaler) 71833ms 32 t ost oscillation start-up timer period 1024t osc 1024t osc t osc = osc1 period 33 t pwrt power up timer period 28 72 132 ms 34 t ioz i/o hi-impedance from mclr low or watchdog timer reset 2 m s 35 t bor brown-out reset pulse width 200 m sv dd b vdd (see d005) 36 t ivrst time for internal reference voltage to become stable 2050 m s v dd mclr internal por pwrt time-out osc time-out internal reset watchdog timer reset 33 32 30 31 34 i/o pins 34 note: refer to figure 21-4 for load conditions. v dd bv dd 35 v bgap = 1.2v v irvst enable internal reference voltage internal reference voltage stable 36
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 257 figure 21-9: timer0 and timer1 external clock timings table 21-8: timer0 and timer1 external clock requirements param no. symbol characteristic min max units conditions 40 tt0h t0cki high pulse width no prescaler 0.5t cy + 20 ns with prescaler 10 ns 41 tt0l t0cki low pulse width no prescaler 0.5t cy + 20 ns with prescaler 10 ns 42 tt0p t0cki period no prescaler t cy + 10 ns with prescaler greater of: 20 n s or t cy + 40 n ns n = prescale value (1, 2, 4,..., 256) 45 tt1h t1cki high time synchronous, no prescaler 0.5t cy + 20 ns synchronous, with prescaler pic18 c xxx 10 ns pic18 lc xxx 25 ns asynchronous pic18 c xxx 30 ns pic18 lc xxx 50 ns 46 tt1l t1cki low time synchronous, no prescaler 0.5t cy + 5 ns synchronous, with prescaler pic18 c xxx 10 ns pic18 lc xxx 25 ns asynchronous pic18 c xxx 30 ns pic18 lc xxx tbd tbd ns 47 tt1p t1cki input period synchronous greater of: 20 n s or t cy + 40 n ns n = prescale value (1, 2, 4, 8) asynchronous 60 ns ft1 t1cki oscillator input frequency range dc 50 khz 48 tcke2tmri delay from external t1cki clock edge to timer increment 2tosc 7tosc note: refer to figure 21-4 for load conditions. 46 47 45 48 41 42 40 t0cki t1oso/t1cki tmr0 or tmr1
pic18cxx2 ds39026b-page 258 preliminary ? 7/99 microchip technology inc. figure 21-10: capture/compare/pwm timings (ccp1 and ccp2) table 21-9: capture/compare/pwm requirements (ccp1 and ccp2) param. no. symbol characteristic min max units conditions 50 tccl ccpx input low time no prescaler 0.5t cy + 20 ns with prescaler pic18 c xxx 10 ns pic18 lc xxx 20 ns 51 tcch ccpx input high time no prescaler 0.5t cy + 20 ns with prescaler pic18 c xxx 10 ns pic18 lc xxx 20 ns 52 tccp ccpx input period 3t cy + 40 n ns n = prescale value (1,4 or 16) 53 tccr ccpx output fall time pic18 c xxx 25 ns pic18 lc xxx 45 ns 54 tccf ccpx output fall time pic18 c xxx 25 ns pic18 lc xxx 45 ns note: refer to figure 21-4 for load conditions. ccpx (capture mode) 50 51 52 ccpx 53 54 (compare or pwm mode)
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 259 figure 21-11: parallel slave port timing (pic18c4x2) table 21-10: parallel slave port requirements (pic18c4x2) param. no. symbol characteristic min max units conditions 62 tdtv2wrh data in valid before wr - or cs - (setup time) 20 25 ns ns extended temp range 63 twrh2dti wr - or cs - to dataCin invalid (hold time) pic18 c xxx 20 ns pic18 lc xxx 35 ns 64 trdl2dtv rd and cs to dataCout valid 80 90 ns ns extended temp range 65 trdh2dti rd - or cs to dataCout invalid 10 30 ns 66 tibfinh inhibit of the ibf flag bit being cleared from wr - or cs - 3t cy note: refer to figure 21-4 for load conditions. re2/cs re0/rd re1/wr rd7:rd0 62 63 64 65
pic18cxx2 ds39026b-page 260 preliminary ? 7/99 microchip technology inc. figure 21-12: example spi master mode timing (cke = 0) table 21-11: example spi mode requirements (master mode, cke = 0) param. no. symbol characteristic min max units conditions 70 tssl2sch, tssl2scl ss to sck or sck - input t cy ns 71 tsch sck input high time (slave mode) continuous 1.25t cy + 30 ns 71a single byte 40 ns note 1 72 tscl sck input low time (slave mode) continuous 1.25t cy + 30 ns 72a single byte 40 ns note 1 73 tdiv2sch, tdiv2scl setup time of sdi data input to sck edge 100 ns 73a t b 2 b last clock edge of byte1 to the 1st clock edge of byte2 1.5t cy + 40 ns note 2 74 tsch2dil, tscl2dil hold time of sdi data input to sck edge 100 ns 75 tdor sdo data output rise time pic18 c xxx 25 ns pic18 lc xxx 45 ns 76 tdof sdo data output fall time 25 ns 78 tscr sck output rise time (master mode) pic18 c xxx 25 ns pic18 lc xxx 45 ns 79 tscf sck output fall time (master mode) 25 ns 80 tsch2dov, tscl2dov sdo data output valid after sck edge pic18 c xxx 50 ns pic18 lc xxx 100 ns note 1: requires the use of parameter # 73a. 2: only if parameter #s 71a and 72a are used. ss sck (ckp = 0) sck (ckp = 1) sdo sdi 70 71 72 73 74 75, 76 78 79 80 79 78 msb lsb bit6 - - - - - -1 msb in lsb in bit6 - - - -1 note: refer to figure 21-4 for load conditions.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 261 figure 21-13: example spi master mode timing (cke = 1) table 21-12: example spi mode requirements (master mode, cke = 1) param. no. symbol characteristic min max units conditions 71 tsch sck input high time (slave mode) continuous 1.25t cy + 30 ns 71a single byte 40 ns note 1 72 tscl sck input low time (slave mode) continuous 1.25t cy + 30 ns 72a single byte 40 ns note 1 73 tdiv2sch, tdiv2scl setup time of sdi data input to sck edge 100 ns 73a t b 2 b last clock edge of byte1 to the 1st clock edge of byte2 1.5t cy + 40 ns note 2 74 tsch2dil, tscl2dil hold time of sdi data input to sck edge 100 ns 75 tdor sdo data output rise time pic18 c xxx 25 ns pic18 lc xxx 45 ns 76 tdof sdo data output fall time 25 ns 78 tscr sck output rise time (master mode) pic18 c xxx 25 ns pic18 lc xxx 45 ns 79 tscf sck output fall time (master mode) 25 ns 80 tsch2dov, tscl2dov sdo data output valid after sck edge pic18 c xxx 50 ns pic18 lc xxx 100 ns 81 tdov2sch, tdov2scl sdo data output setup to sck edge t cy ns note 1: requires the use of parameter # 73a. 2: only if parameter #s 71a and 72a are used. ss sck (ckp = 0) sck (ckp = 1) sdo sdi 81 71 72 74 75, 76 78 80 msb 79 73 msb in bit6 - - - - - -1 lsb in bit6 - - - -1 lsb note: refer to figure 21-4 for load conditions.
pic18cxx2 ds39026b-page 262 preliminary ? 7/99 microchip technology inc. figure 21-14: example spi slave mode timing (cke = 0) table 21-13: example spi mode requirements (slave mode timing (cke = 0)) parm. no. symbol characteristic min max units conditions 70 tssl2sch, tssl2scl ss to sck or sck - input t cy ns 71 tsch sck input high time (slave mode) continuous 1.25t cy + 30 ns 71a single byte 40 ns note 1 72 tscl sck input low time (slave mode) continuous 1.25t cy + 30 ns 72a single byte 40 ns note 1 73 tdiv2sch, tdiv2scl setup time of sdi data input to sck edge 100 ns 73a t b 2 b last clock edge of byte1 to the 1st clock edge of byte2 1.5t cy + 40 ns note 2 74 tsch2dil, tscl2dil hold time of sdi data input to sck edge 100 ns 75 tdor sdo data output rise time pic18 c xxx 25 ns pic18 lc xxx 45 ns 76 tdof sdo data output fall time 25 ns 77 tssh2doz ss - to sdo output hi-impedance 10 50 ns 78 tscr sck output rise time (master mode) pic18 c xxx 25 ns pic18 lc xxx 45 ns 79 tscf sck output fall time (master mode) 25 ns 80 tsch2dov, tscl2dov sdo data output valid after sck edge pic18 c xxx 50 ns pic18 lc xxx 100 ns 83 tsch2ssh, tscl2ssh ss - after sck edge 1.5t cy + 40 ns note 1: requires the use of parameter # 73a. 2: only if parameter #s 71a and 72a are used. ss sck (ckp = 0) sck (ckp = 1) sdo sdi 70 71 72 73 74 75, 76 77 78 79 80 79 78 sdi msb lsb bit6 - - - - - -1 msb in bit6 - - - -1 lsb in 83 note: refer to figure 21-4 for load conditions.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 263 figure 21-15: example spi slave mode timing (cke = 1) table 21-14: example spi slave mode requirements (cke = 1) parm. no. symbol characteristic min max units conditions 70 tssl2sch, tssl2scl ss to sck or sck - input t cy ns 71 tsch sck input high time (slave mode) continuous 1.25t cy + 30 ns 71a single byte 40 ns note 1 72 tscl sck input low time (slave mode) continuous 1.25t cy + 30 ns 72a single byte 40 ns note 1 73a t b 2 b last clock edge of byte1 to the 1st clock edge of byte2 1.5t cy + 40 ns note 2 74 tsch2dil, tscl2dil hold time of sdi data input to sck edge 100 ns 75 tdor sdo data output rise time pic18 c xxx 25 ns pic18 lc xxx 45 ns 76 tdof sdo data output fall time 25 ns 77 tssh2doz ss - to sdo output hi-impedance 10 50 ns 78 tscr sck output rise time (master mode) pic18 c xxx 25 ns pic18 lc xxx 45 ns 79 tscf sck output fall time (master mode) 25 ns 80 tsch2dov, tscl2dov sdo data output valid after sck edge pic18 c xxx 50 ns pic18 lc xxx 100 ns 82 tssl2dov sdo data output valid after ss edge pic18 c xxx 50 ns pic18 lc xxx 100 ns 83 tsch2ssh, tscl2ssh ss - after sck edge 1.5t cy + 40 ns note 1: requires the use of parameter # 73a. 2: only if parameter #s 71a and 72a are used. ss sck (ckp = 0) sck (ckp = 1) sdo sdi 70 71 72 82 sdi 74 75, 76 msb bit6 - - - - - -1 lsb 77 msb in bit6 - - - -1 lsb in 80 83 note: refer to figure 21-4 for load conditions.
pic18cxx2 ds39026b-page 264 preliminary ? 7/99 microchip technology inc. figure 21-16: i 2 c bus start/stop bits timing table 21-15: i 2 c bus start/stop bits requirements (slave mode) parm. no. symbol characteristic min max units conditions 90 t su : sta start condition 100 khz mode 4700 ns only relevant for repeated start condition setup time 400 khz mode 600 91 t hd : sta start condition 100 khz mode 4000 ns after this period the first clock pulse is generated hold time 400 khz mode 600 92 t su : sto stop condition 100 khz mode 4700 ns setup time 400 khz mode 600 93 t hd : sto stop condition 100 khz mode 4000 ns hold time 400 khz mode 600 note: refer to figure 21-4 for load conditions. 91 92 93 scl sda start condition stop condition 90
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 265 figure 21-17: i 2 c bus data timing table 21-16: i 2 c bus data requirements (slave mode) param. no. symbol characteristic min max units conditions 100 t high clock high time 100 khz mode 4.0 m s pic18cxxx must operate at a minimum of 1.5 mhz 400 khz mode 0.6 m s pic18cxxx must operate at a minimum of 10 mhz ssp module 1.5t cy 101 t low clock low time 100 khz mode 4.7 m s pic18cxxx must operate at a minimum of 1.5 mhz 400 khz mode 1.3 m s pic18cxxx must operate at a minimum of 10 mhz ssp module 1.5t cy 102 t r sda and scl rise time 100 khz mode 1000 ns 400 khz mode 20 + 0.1cb 300 ns cb is specified to be from 10 to 400 pf 103 t f sda and scl fall time 100 khz mode 300 ns 400 khz mode 20 + 0.1cb 300 ns cb is specified to be from 10 to 400 pf 90 t su : sta start condition setup time 100 khz mode 4.7 m s only relevant for repeated start condition 400 khz mode 0.6 m s 91 t hd : sta start condition hold time 100 khz mode 4.0 m s after this period the first clock pulse is generated 400 khz mode 0.6 m s 106 t hd : dat data input hold time 100 khz mode 0 ns 400 khz mode 0 0.9 m s 107 t su : dat data input setup time 100 khz mode 250 ns note 2 400 khz mode 100 ns 92 t su : sto stop condition setup time 100 khz mode 4.7 m s 400 khz mode 0.6 m s 109 t aa output valid from clock 100 khz mode 3500 ns note 1 400 khz mode ns 110 t buf bus free time 100 khz mode 4.7 m s time the bus must be free before a new transmission can start 400 khz mode 1.3 m s d102 cb bus capacitive loading 400 pf note 1: as a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (min. 300 ns) of the falling edge of scl to avoid unintended generation of start or stop conditions. 2: a fast-mode i 2 c bus device can be used in a standard-mode i 2 c bus system, but the requirement tsu;dat 3 250 ns must then be met. this will automatically be the case if the device does not stretch the low period of the scl signal. if such a device does stretch the low period of the scl signal, it must output the next data bit to the sda line. t r max. + tsu;dat = 1000 + 250 = 1250 ns (according to the standard-mode i 2 c bus specification) before the scl line is released. note: refer to figure 21-4 for load conditions . 90 91 92 100 101 103 106 107 109 109 110 102 scl sda in sda out
pic18cxx2 ds39026b-page 266 preliminary ? 7/99 microchip technology inc. figure 21-18: master ssp i 2 c bus start/stop bits timing waveforms table 21-17: master ssp i 2 c bus start/stop bits requirements param. no. symbol characteristic min max units conditions 90 t su : sta start condition 100 khz mode 2(t osc )(brg + 1) ns only relevant for repeated start condition setup time 400 khz mode 2(t osc )(brg + 1) 1 mhz mode ( 1 ) 2(t osc )(brg + 1) 91 t hd : sta start condition 100 khz mode 2(t osc )(brg + 1) ns after this period the first clock pulse is generated hold time 400 khz mode 2(t osc )(brg + 1) 1 mhz mode ( 1 ) 2(t osc )(brg + 1) 92 t su : sto stop condition 100 khz mode 2(t osc )(brg + 1) ns setup time 400 khz mode 2(t osc )(brg + 1) 1 mhz mode ( 1 ) 2(t osc )(brg + 1) 93 t hd : sto stop condition 100 khz mode 2(t osc )(brg + 1) ns hold time 400 khz mode 2(t osc )(brg + 1) 1 mhz mode ( 1 ) 2(t osc )(brg + 1) note 1: maximum pin capacitance = 10 pf for all i 2 c pins. note: refer to figure 21-4 for load conditions. 91 93 scl sda start condition stop condition 90 92
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 267 figure 21-19: master ssp i 2 c bus data timing table 21-18: master ssp i 2 c bus data requirements param. no. symbol characteristic min max units conditions 100 t high clock high time 100 khz mode 2(t osc )(brg + 1) ms 400 khz mode 2(t osc )(brg + 1) ms 1 mhz mode ( 1 ) 2(t osc )(brg + 1) ms 101 t low clock low time 100 khz mode 2(t osc )(brg + 1) ms 400 khz mode 2(t osc )(brg + 1) ms 1 mhz mode ( 1 ) 2(t osc )(brg + 1) ms 102 t r sda and scl rise time 100 khz mode 1000 ns cb is specified to be from 10 to 400 pf 400 khz mode 20 + 0.1cb 300 ns 1 mhz mode ( 1 ) 300 ns 103 t f sda and scl fall time 100 khz mode 300 ns cb is specified to be from 10 to 400 pf 400 khz mode 20 + 0.1cb 300 ns 1 mhz mode ( 1 ) 100 ns 90 t su : sta start condition setup time 100 khz mode 2(t osc )(brg + 1) ms only relevant for repeated start condition 400 khz mode 2(t osc )(brg + 1) ms 1 mhz mode ( 1 ) 2(t osc )(brg + 1) ms 91 t hd : sta start condition hold time 100 khz mode 2(t osc )(brg + 1) ms after this period the first clock pulse is generated 400 khz mode 2(t osc )(brg + 1) ms 1 mhz mode ( 1 ) 2(t osc )(brg + 1) ms 106 t hd : dat data input hold time 100 khz mode 0 ns 400 khz mode 0 0.9 ms 1 mhz mode ( 1 ) tbd ns 107 t su : dat data input setup time 100 khz mode 250 ns note 2 400 khz mode 100 ns 1 mhz mode ( 1 ) tbd ns 92 t su : sto stop condition setup time 100 khz mode 2(t osc )(brg + 1) ms 400 khz mode 2(t osc )(brg + 1) ms 1 mhz mode ( 1 ) 2(t osc )(brg + 1) ms 109 t aa output valid from clock 100 khz mode 3500 ns 400 khz mode 1000 ns 1 mhz mode ( 1 ) ns 110 t buf bus free time 100 khz mode 4.7 ms time the bus must be free before a new transmis- sion can start 400 khz mode 1.3 ms 1 mhz mode ( 1 ) tbd ms d102 cb bus capacitive loading 400 pf note 1: maximum pin capacitance = 10 pf for all i 2 c pins. 2: a fast-mode i 2 c bus device can be used in a standard-mode i 2 c bus system, but parameter #107 3 250 ns must then be met. this will automatically be the case if the device does not stretch the low period of the scl signal. if such a device does stretch the low period of the scl signal, it must output the next data bit to the sda line. parameter #102.+ parameter #107 = 1000 + 250 = 1250 ns (for 100 khz-mode) before the scl line is released. note: refer to figure 21-4 for load conditions. 90 91 92 100 101 103 106 107 109 109 110 102 scl sda in sda out
pic18cxx2 ds39026b-page 268 preliminary ? 7/99 microchip technology inc. figure 21-20: usart synchronous transmission (master/slave) timing table 21-19: usart synchronous transmission requirements param. no. symbol characteristic min max units conditions 120 tckh2dtv sync xmit (master & slave) clock high to data out valid pic18 c xxx 40ns pic18 lc xxx 100 ns 121 tckrf clock out rise time and fall time (master mode) pic18 c xxx 20 ns pic18 lc xxx 50 ns 122 tdtrf data out rise time and fall time pic18 c xxx 20 ns pic18 lc xxx 50 ns note: refer to figure 21-4 for load conditions. 121 121 120 122 rc6/tx/ck rc7/rx/dt pin pin
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 269 figure 21-21: usart synchronous receive (master/slave) timing table 21-20: usart synchronous receive requirements param. no. symbol characteristic min max units conditions 125 tdtv2ckl sync rcv (master & slave) data hold before ck (dt hold time) 10 ns 126 tckl2dtl data hold after ck (dt hold time) 15 ns note: refer to figure 21-4 for load conditions. 125 126 rc6/tx/ck rc7/rx/dt pin pin
pic18cxx2 ds39026b-page 270 preliminary ? 7/99 microchip technology inc. table 21-21: a/d converter characteristics: pic18cxx2 (industrial, extended) pic18lcxx2 (industrial) param no. symbol characteristic min typ max units conditions a01 n r resolution 10 tbd bit bit v ref = v dd 3 3.0v v ref = v dd < 3.0v a03 e il integral linearity error <1 tbd lsb lsb v ref = v dd 3 3.0v v ref = v dd < 3.0v a04 e dl differential linearity error <1 tbd lsb lsb v ref = v dd 3 3.0v v ref = v dd < 3.0v a05 e fs full scale error <1 tbd lsb lsb v ref = v dd 3 3.0v v ref = v dd < 3.0v a06 e off offset error <1 tbd lsb lsb v ref = v dd 3 3.0v v ref = v dd < 3.0v a10 monotonicity guaranteed ( 3 ) v ss v ain v ref a20 v ref reference voltage (v refh - v refl ) 0v v a20a 3v v for 10-bit resolution a21 v refh reference voltage high av ss av dd + 0.3v v a22 v refl reference voltage low av ss - 0.3v av dd v a25 v ain analog input voltage av ss - 0.3v v ref + 0.3v v a30 z ain recommended impedance of analog voltage source 10.0 k w a40 i ad a/d conversion current (v dd ) pic18 c xxx 180 m a average current consumption when a/d is on. (note 1) pic18 lc xxx 90 m a a50 i ref v ref input current (note 2) 10 1000 10 m a m a during v ain acquisition. based on differential of v hold to v ain . to charge c hold see section 16.0. during a/d conversion cycle note 1: when a/d is off, it will not consume any current other than minor leakage current. the power-down current spec includes any such leakage from the a/d module. v ref current is from ra2/an2/v ref - and ra3/an3/v ref + pins or av dd and av ss pins, whichever is selected as reference input. 2: v ss v ain v ref 3: the a/d conversion result either increases or remains constant as the analog input increases.
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 271 figure 21-22: a/d conversion timing table 21-22: a/d conversion requirements param no. symbol characteristic min max units conditions 130 t ad a/d clock period pic18 c xxx 1.6 20 (5) m s t osc based, v ref 3 3.0v pic18 lc xxx 3.0 20 (5) m st osc based, v ref full range pic18 c xxx 2.0 6.0 m s a/d rc mode pic18 lc xxx 3.0 9.0 m s a/d rc mode 131 t cnv conversion time (not including acquisition time) (note 1) 11 12 t ad 132 t acq acquisition time (note 3) 15 10 m s m s -40 c te m p 125 c 0 c te m p 125 c 135 t swc switching time from convert ? sample note 4 136 t amp amplifier settling time (note 2) 1 m s this may be used if the new input voltage has not changed by more than 1lsb (i.e. 5 mv @ 5.12v) from the last sampled voltage (as stated on c hold ). note 1: adres register may be read on the following t cy cycle. 2: see the section 16.0 for minimum conditions, when input voltage has changed more than 1 lsb. 3: the time for the holding capacitor to acquire the new input voltage, when the voltage changes full scale after the conversion (av dd to av ss , or av ss to av dd ). the source impedance ( r s ) on the input channels is 50 w . 4: on the next q4 cycle of the device clock. 5: the time of the a/d clock period is dependent on the device frequency and the t ad clock divider. 131 130 132 bsf adcon0, go q4 a/d clk a/d data adres adif go sample old_data sampling stopped done new_data note 2 987 21 0 note 1: if the a/d clock source is selected as rc, a time of t cy is added before the a/d clock starts. this allows the sleep instruction to be executed. 2: this is a minimal rc delay (typically 100 ns), which also disconnects the holding capacitor from the analog input. . . . . . . t cy
pic18cxx2 ds39026b-page 272 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 273 22.0 dc and ac characteristics graphs and tables graphs and tables not available at this time.
pic18cxx2 ds39026b-page 274 preliminary ? 7/99 microchip technology inc. notes:
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 275 23.0 packaging information 23.1 package marking information not available at time of printing. will be made available after definition of qs9000 compliant standard 23.2 package details the following sections give the technical details of the packages.
pic18cxx2 ds39026b-page 276 preliminary ? 7/99 microchip technology inc. package type: 28-lead skinny plastic dual in-line (sp) C 300 mil * controlling parameter. ? dimension b1 does not include dam-bar protrusions. dam-bar protrusions shall not exceed 0.003 (0.076 mm) per side or 0.006 (0.152 mm) more than dimension b1. ? dimensions d and e do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010 (0.254 mm) per side or 0.020 (0.508 mm) more than dimensions d or e. jedec equivalent: mo-095 ah 0.320 0.270 0.280 1.345 0.125 0.015 0.070 0.140 0.008 0.000 0.040 0.016 mold draft angle bottom mold draft angle top overall row spacing radius to radius width molded package width tip to seating plane base to seating plane top of lead to seating plane top to seating plane upper lead width lower lead width pcb row spacing package length lead thickness shoulder radius number of pins dimension limits pitch units e ? b eb e1 a a1 a2 l d ? a c r n b1 ? b p min min 0.295 0.288 5 5 10 0.350 0.283 10 0.380 0.295 15 15 0.090 1.365 0.130 0.020 0.150 0.010 0.005 nom inches* 28 0.053 0.019 0.100 0.300 1.385 0.135 0.025 0.110 0.160 0.012 0.010 0.065 0.022 max 7.49 7.30 7.11 8.89 7.18 5 8.13 6.86 5 10 10 15 15 9.65 7.49 34.67 3.30 0.51 2.29 3.81 0.25 0.13 1.33 0.48 2.54 7.62 millimeters 1.78 34.16 3.18 0.38 3.56 0.20 0.00 1.02 0.41 nom 2.79 35.18 3.43 0.64 4.06 0.30 0.25 max 28 1.65 0.56 n 1 2 r d e c eb b e1 a p l a1 b b1 a a2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 277 package type: 28-lead ceramic dual in-line with window (jw) C 600 mil * controlling parameter. jedec equivalent: mo-103 ab n 1 2 r min window diameter overall row spacing radius to radius width package width package length tip to seating plane base to seating plane top of lead to seating plane top to seating plane lead thickness shoulder radius upper lead width lower lead width number of pins pcb row spacing dimension limits units pitch w eb e1 a2 d e l a a1 c r b1 b p n 7.37 1.40 3.70 5.08 0.30 0.25 1.65 0.53 2.59 0.280 0.660 0.580 0.520 1.460 0.138 0.035 0.128 0.185 0.010 0.270 0.610 0.560 0.015 0.514 1.430 0.125 0.110 0.170 0.008 0.290 0.710 0.600 0.055 0.526 1.490 0.150 0.146 0.200 0.012 0.005 0.058 0.019 0.100 0.600 inches* 0.098 0.000 0.050 0.016 nom max 28 0.102 0.010 0.065 0.021 37.08 6.86 15.49 14.22 13.06 36.32 3.18 0.38 2.78 4.32 0.20 7.11 16.76 14.73 18.03 15.24 0.89 3.49 13.21 3.24 4.70 0.25 13.36 37.85 3.81 nom millimeters 0.00 1.27 0.41 2.49 min 2.54 0.13 1.46 0.47 28 15.24 max d e w c e1 eb p a1 l b1 b a2 a
pic18cxx2 ds39026b-page 278 preliminary ? 7/99 microchip technology inc. package type: 28-lead plastic small outline (so) C wide, 300 mil min p pitch mold draft angle bottom mold draft angle top lower lead width radius centerline gull wing radius shoulder radius chamfer distance outside dimension molded package width molded package length shoulder height overall pack. height lead thickness foot angle foot length standoff number of pins b a b ? c f x a2 a1 a n e1 l l1 r1 r2 e ? d ? dimension limits units 1.27 0.050 8 12 12 0.017 0 0.014 0 0.019 15 15 0.011 0.015 0.016 0.005 0.005 0.020 0.407 0.296 0.706 0.008 0.058 0.099 28 0.394 0.011 0.009 0.010 0 0.005 0.005 0.010 0.292 0.700 0.004 0.048 0.093 0.419 0.012 0.020 0.021 0.010 0.010 0.029 48 0.299 0.712 0.011 0.068 0.104 0.36 0 0 12 12 0.42 15 15 0.48 10.33 17.93 10.01 0.23 0.25 0.28 0.13 0.13 0.25 0 7.42 0.10 1.22 2.36 17.78 10.64 0.41 4 0.27 0.38 0.13 0.13 0.50 0.53 0.30 0.51 0.25 0.25 0.74 7.51 0.19 28 2.50 1.47 18.08 7.59 0.28 2.64 1.73 nom inches* max nom millimeters min max n 1 2 r1 r2 d p b e1 e l1 l c b 45 x f a1 a a a2 * controlling parameter. ? dimension b does not include dam-bar protrusions. dam-bar protrusions shall not exceed 0.003 (0.076 mm) per side or 0.006 (0.152 mm) more than dimension b. ? dimensions d and e do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010 (0.254 mm) per side or 0.020 (0.508 mm) more than dimensions d or e. jedec e q uivalent: ms-013 ae
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 279 package type: 40-lead plastic dual in-line (p) C 600 mil * controlling parameter. ? dimension b1 does not include dam-bar protrusions. dam-bar protrusions shall not exceed 0.003 (0.076 mm) per side or 0.006 (0.152 mm) more than dimension b1. ? dimensions d and e do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010 (0.254 mm) per side or 0.020 (0.508 mm) more than dimensions d or e. jedec equivalent: ms-011 ac n 2 1 r top to seating plane mold draft angle bottom mold draft angle top overall row spacing radius to radius width molded package width tip to seating plane base to seating plane top of lead to seating plane package length e1 b eb a l e ? d ? a2 a1 0.670 0.585 0.540 2.023 0.135 0.040 0.113 0.545 5 5 0.630 0.125 0.530 2.013 0.020 0.073 0.565 10 0.610 10 0.130 0.535 2.018 0.020 0.093 16.00 13.84 13.46 51.13 3.18 0.51 1.85 15 15 14.35 5 5 10 15.49 10 3.30 13.59 51.26 0.51 2.36 14.86 17.02 15 15 13.72 51.38 3.43 1.02 2.87 pcb row spacing lead thickness shoulder radius upper lead width lower lead width pitch number of pins dimension limits units p c a r b b1 ? n 0.160 0.011 0.010 0.055 0.020 nom inches* 0.110 0.009 0.000 0.045 0.016 min 0.100 0.160 0.010 0.005 0.050 0.018 40 0.600 max 2.79 0.23 0.00 1.14 0.41 min 2.54 4.06 0.25 0.13 1.27 0.46 nom millimeters 15.24 40 4.06 0.28 0.25 1.40 0.51 max a1 d e c b eb e1 a p l b b1 a a2
pic18cxx2 ds39026b-page 280 preliminary ? 7/99 microchip technology inc. package type: 40-lead ceramic dual in-line with window (jw) C 600 mil * controlling parameter. jedec equivalent: mo-103 ac n 1 2 r window diameter overall row spacing radius to radius width package width package length tip to seating plane base to seating plane top of lead to seating plane top to seating plane lead thickness shoulder radius upper lead width lower lead width number of pins pcb row spacing dimension limits pitch e1 w eb d e l a2 a1 a c p b1 r b n 9.14 18.03 15.24 13.36 52.32 3.68 3.89 5.59 0.36 0.25 0.58 2.59 max 0.014 0.011 0.008 0.350 0.660 0.580 0.520 2.050 0.140 0.035 0.135 0.205 0.560 0.340 0.610 0.514 2.040 0.135 0.015 0.117 0.190 0.600 0.360 0.710 0.526 2.060 0.145 0.055 0.153 0.220 0.005 0.053 0.020 0.100 0.600 nom 0.000 0.050 0.016 0.098 min 40 0.102 0.010 0.055 0.023 max 0.28 0.20 14.22 15.49 8.64 13.06 51.82 3.43 0.38 2.97 4.83 14.73 16.76 8.89 13.21 52.07 3.56 0.89 3.43 5.21 min 2.49 1.27 0.00 0.41 2.54 1.33 0.13 0.50 15.24 nom 40 1.40 1.40 d w e c eb e1 p l a1 b1 b a a2 units inches* millimeters
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 281 package type: 44-lead plastic thin quad flatpack (pt) 10x10x1 mm body, 1.0/0.1 mm lead form 0.025 0.390 0.390 0.463 0.463 0.012 0.004 0.003 0.005 0.003 0.003 0.002 0.015 0.039 p mold draft angle bottom mold draft angle top pin 1 corner chamfer molded pack. width molded pack. length outside tip width outside tip length lower lead width lead thickness radius centerline gull wing radius shoulder radius shoulder height overall pack. height pins along width number of pins foot length foot angle standoff d ? b x a e ? l d1 e1 b ? c l1 f a1 r1 r2 a2 n1 a n dimension limits pitch units min 0.398 0.394 5 5 12 0.035 0.394 10 0.045 0.398 15 15 0.010 0 0.472 0.472 0.015 0.006 0.008 3.5 0.025 0.006 0.003 0.004 0.043 11 44 0.015 0.482 0.482 0.018 0.008 0.013 7 0.008 0.010 0.006 0.035 0.047 10.10 10.00 9.90 12 10 0.89 10.00 5 0.64 9.90 5 15 15 1.14 10.10 12.00 12.00 0.38 0.15 0.20 3.5 0.25 0.14 0.08 0.10 0.64 1.10 11 44 0.13 11.75 11.75 0.30 0.09 0.08 0 0.38 0.08 0.08 0.05 1.00 0.38 12.25 12.25 0.45 0.20 0.33 7 0.89 0.20 0.25 0.15 1.20 min nom inches 0.031 max 0.80 millimeters* nom max x x 45 n 1 2 r2 r1 l1 l b c f d1 d b p # leads = n1 e e1 a a1 a2 a * controlling parameter. ? dimension b does not include dam-bar protrusions. dam-bar protrusions shall not exceed 0.003 (0.076 mm) per side or 0.006 (0.152 mm) more than dimension b. ? dimensions d and e do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010 (0.254 mm) per side or 0.020 (0.508 mm) more than dimensions d or e. jedec equivalent: ms-026 acb
pic18cxx2 ds39026b-page 282 preliminary ? 7/99 microchip technology inc. package type: 44-lead plastic leaded chip carrier (l) C square * controlling parameter. ? dimension b1 does not include dam-bar protrusions. dam-bar protrusions shall not exceed 0.003 (0.076 mm) per side or 0.006 (0.152 mm) more than dimension b1. ? dimensions d and e do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010" (0.254 mm) per side or 0.020" (0.508 mm) more than dimensions d or e. jedec equivalent: mo-047 ac 0.015 0.003 0.050 0.015 0.026 0.008 0.610 0.610 0.650 0.650 0.685 0.685 0.000 0.040 0.024 0.015 0.095 0.165 min p pitch mold draft angle bottom mold draft angle top j-bend inside radius shoulder inside radius upper lead length lower lead width upper lead width lead thickness pins along width footprint length footprint width molded pack. length molded pack. width overall pack. length overall pack. width corner chamfer (other) corner chamfer (1) side 1 chamfer dim. shoulder height overall pack. height standoff r2 r1 a b l b b1 ? d2 e2 ch2 ch1 a3 a2 e1 c n1 e ? d ? d1 a1 a number of pins dimension limits units n 1.27 0.050 0 0 0.005 0.025 5 5 0.058 0.018 0.029 0.035 0.010 0.065 0.021 0.032 10 10 0.690 0.620 0.010 0.620 11 0.653 0.653 0.690 0.005 0.045 0.029 0.023 0.103 0.173 0.695 0.012 0.630 0.630 0.656 0.656 0.695 0.010 0.050 0.034 0.030 0.110 0.180 0.64 0.13 1.46 0.46 0.74 0.08 0.38 0 0 1.27 0.38 0.66 5 5 0.25 0.89 10 10 1.65 0.53 0.81 0.25 15.75 15.75 16.59 16.59 17.53 17.53 0.13 1.14 0.74 0.57 2.60 4.38 17.40 15.49 0.20 15.49 16.51 16.51 17.40 0.00 1.02 0.61 0.38 2.41 4.19 17.65 11 16.00 0.30 16.00 16.66 16.66 17.65 0.25 1.27 0.86 0.76 2.79 4.57 inches* nom 44 max millimeters min nom max 44 1 ch2 x 45 n ch1 x 45 2 b r2 a1 r1 c e2 d1 d # leads = n1 e1 e a p l a3 a2 a 35 b1 b d2
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 283 appendix a: revision history revision a this is a new data sheet. appendix b: device differences the differences between the devices listed in this data sheet are shown in table 23-1. table 23-1: device differences feature pic18c242 pic18c252 pic18c442 pic18c452 program memory (bytes) 8k 16k 8k 16k data memory (bytes) 16k 32k 16k 32k a/d channels 5 5 8 8 parallel slave port (psp) no no yes yes package types 28-pin dip 28-pin soic 28-pin jw 28-pin dip 28-pin soic 28-pin jw 40-pin dip 40-pin plcc 40-pin tqfp 40-pin jw 40-pin dip 40-pin plcc 40-pin tqfp 40-pin jw
pic18cxx2 ds39026b-page 284 preliminary ? 7/99 microchip technology inc. appendix c: conversion considerations this appendix discusses the considerations for con- verting from previous version of a device to the ones listed in this data sheet. typically these changes are due to the differences in the process technology used. an example of this type of conversion is from a pic16c74a to a pic16c74b. not applicable appendix d: migration from baseline to enhanced devices this section discusses how to migrate from a baseline device (i.e., pic16c5x) to an enhanced mcu device (i.e., pic18cxxx). the following are the list of modifications over the pic16c5x microcontroller family: not currently available
pic18cxx2 ? 7/99 microchip technology inc. preliminary ds39026b-page 285 appendix e: migration from midrange to enhanced devices this section discusses how to migrate from a midrange device (i.e., pic16cxxx) to an enhanced device (i.e., pic18cxxx). the following are the list of modifications over the pic16cxxx microcontroller family: not currently available appendix f: migration from high-end to enhanced devices this section discusses how to migrate from a high-end device (i.e., pic17cxxx) to an enhance mcu device (i.e., pic18cxxx). the following are the list of modifications over the pic17cxxx microcontroller family: not currently available
pic18cxx2 ds39026b-page 286 preliminary ? 7/99 microchip technology inc. notes:
7/99 microchip technology inc. preliminary ds39026b-page 287 pic18cxx2 index a a/d ................................................................................... 167 a/d converter flag (adif bit) ................................. 169 a/d converter interrupt, configuring ....................... 170 adcon0 register .................................................... 167 adcon1 register ............................................ 167, 168 adres register .............................................. 167, 169 analog port pins .................................................. 89, 90 analog port pins, configuring .................................. 171 block diagram .......................................................... 169 block diagram, analog input model ......................... 170 configuring the module ............................................ 170 conversion clock (t ad ) ........................................... 171 conversion status (go/done bit) .......................... 169 conversions ............................................................. 172 converter characteristics ........................................ 270 converter characteristics .......................................... 249 effects of a reset ..................................................... 179 operation during sleep ........................................... 179 sampling requirements ........................................... 170 special event trigger (ccp) ............................ 112, 172 timing diagram ........................................................ 271 absolute maximum ratings ............................................. 241 adcon0 register ............................................................ 167 go/done bit ........................................................... 169 adcon1 register .................................................... 167, 168 addlw ............................................................................ 197 addwf ............................................................................ 197 addwfc ......................................................................... 198 adres register ...................................................... 167, 169 aks .................................................................................. 139 analog-to-digital converter. see a/d andlw ............................................................................ 198 andwf ............................................................................ 199 assembler mpasm assembler .................................................. 235 b baud rate generator ....................................................... 136 bcf .................................................................................. 200 bf .................................................................................... 139 block diagrams baud rate generator ............................................... 136 ssp (spi mode) ....................................................... 121 timer1 ...................................................................... 106 brg ................................................................................. 136 brown-out reset (bor) ............................................. 24, 181 timing diagram ........................................................ 256 bsf .......................... 199, 200, 201, 202, 203, 205, 206, 221 btfsc ............................................................................. 204 btfss ............................................................................. 204 btg .................................................................................. 205 bus collision during a restart condition .................... 148 bus collision during a start condition ............................. 146 bus collision during a stop condition ............................. 149 c c ........................................................................................ 54 call ................................................................................ 206 capture (ccp module) .................................................... 111 block diagram .......................................................... 111 ccp pin configuration ............................................. 111 ccpr1h:ccpr1l registers ................................... 111 changing between capture prescalers ................... 111 software interrupt .................................................... 111 timer1 mode selection ............................................ 111 capture/compare/pwm (ccp) ....................................... 109 ccp1 ....................................................................... 110 ccpr1h register ........................................... 110 ccpr1l register ............................................ 110 ccp2 ....................................................................... 110 ccpr2h register ........................................... 110 ccpr2l register ............................................ 110 interaction of two ccp modules ............................. 110 timer resources ..................................................... 110 timing diagram ....................................................... 258 clocking scheme ............................................................... 37 clrf ....................................................................... 207, 225 clrwdt ......................................................................... 207 code examples loading the sspbuf register ................................. 122 code protection ....................................................... 181, 189 comf .............................................................................. 208 compare (ccp module) .................................................. 112 block diagram ......................................................... 112 ccp pin configuration ............................................ 112 ccpr1h:ccpr1l registers .................................. 112 software interrupt .................................................... 112 special event trigger ........................ 99, 107, 112, 172 timer1 mode selection ............................................ 112 configuration bits ............................................................ 181 conversion considerations .............................................. 286 cpfseq .......................................................................... 208 cpfsgt .......................................................................... 209 cpfslt ........................................................................... 209 d data memory ..................................................................... 40 general purpose registers ....................................... 40 special function registers ........................................ 40 daw ................................................................................ 210 dc ..................................................................................... 54 dc characteristics ................................... 243, 244, 247, 248 decf ............................................................................... 210 decfsnz ........................................................................ 211 decfsz .......................................................................... 211 development support ...................................................... 235 device differences ........................................................... 285 direct addressing .............................................................. 49 e electrical characteristics ................................................. 241 errata ................................................................................... 4 f firmware instructions ...................................................... 191 fs0 .................................................................................... 54 fs1 .................................................................................... 54 fs2 .................................................................................... 54 fs3 .................................................................................... 54 g general call address sequence ..................................... 133 general call address support ......................................... 133 goto .............................................................................. 212 i i/o ports ............................................................................ 77 i 2 c (ssp module) ............................................................ 128 ack pulse ....................................................... 129, 130 addressing ............................................................... 129
pic18cxx2 ds39026b-page 288 preliminary 7/99 microchip technology inc. block diagram .......................................................... 128 read/write bit information (r/w bit) ............... 129, 130 reception ................................................................. 130 serial clock (rc3/sck/scl) ................................... 130 slave mode .............................................................. 129 timing diagram, data .............................................. 265 timing diagram, start/stop bits ............................... 264 transmission ............................................................ 130 i 2 c master mode reception ............................................. 139 i 2 c master mode restart condition ................................. 138 i 2 c module acknowledge sequence timing ................................ 142 baud rate generator ............................................... 136 brg block diagram ................................................. 136 brg reset due to sda collision ............................. 147 brg timing ............................................................. 136 bus collision acknowledge .................................................... 145 restart condition ............................................. 148 restart condition timing (case1) .................... 148 restart condition timing (case2) .................... 148 start condition ................................................. 146 start condition timing ............................. 146, 147 stop condition ................................................. 149 stop condition timing (case1) ........................ 149 stop condition timing (case2) ........................ 149 transmit timing ............................................... 145 bus collision timing .................................................. 145 clock arbitration ....................................................... 144 clock arbitration timing (master transmit) .............. 144 general call address support ................................. 133 master mode 7-bit reception timing ........................ 141 master mode operation ........................................... 135 master mode start condition ................................... 137 master mode transmission ...................................... 139 master mode transmit sequence ............................ 135 multi-master mode ................................................... 145 repeat start condition timing .................................. 138 stop condition receive or transmit timing .............. 143 stop condition timing ............................................... 142 waveforms for 7-bit reception ................................ 130 waveforms for 7-bit transmission ........................... 130 id locations ............................................................. 181, 189 incf ................................................................................. 212 incfsnz .......................................................................... 213 incfsz ............................................................................ 213 in-circuit serial programming (icsp) ...................... 181, 189 indirect addressing ............................................................ 49 fsr register ............................................................. 48 instruction cycle ................................................................. 37 instruction flow/pipelining ................................................. 38 instruction format ............................................................ 193 instruction set .................................................................. 191 addlw .................................................................... 197 addwf .................................................................... 197 addwfc ................................................................. 198 andlw .................................................................... 198 andwf .................................................................... 199 bcf .......................................................................... 200 bsf .................. 199, 200, 201, 202, 203, 205, 206, 221 btfsc ..................................................................... 204 btfss ..................................................................... 204 btg .......................................................................... 205 call ........................................................................ 206 clrf ................................................................ 207, 225 clrwdt .................................................................. 207 comf ...................................................................... 208 cpfseq .................................................................. 208 cpfsgt .................................................................. 209 cpfslt ................................................................... 209 daw ........................................................................ 210 decf ....................................................................... 210 decfsnz ................................................................ 211 decfsz .................................................................. 211 goto ...................................................................... 212 incf ........................................................................ 212 incfsnz ................................................................. 213 incfsz .................................................................... 213 iorlw ..................................................................... 214 iorwf ..................................................................... 214 movfp .................................................................... 216 movlb .................................................................... 215 movlr ............................................................ 215, 216 movlw ................................................................... 217 movwf ................................................................... 217 mullw .................................................................... 218 mulwf .................................................................... 218 negw ..................................................................... 219 nop ......................................................................... 219 retfie ............................................................ 221, 222 retlw .................................................................... 222 return .................................................................. 223 rlcf ....................................................................... 223 rlncf ..................................................................... 224 rrcf ....................................................................... 224 rrncf .................................................................... 225 sleep ..................................................................... 226 sublw .................................................................... 227 subwf .................................................... 226, 227, 228 subwfb ................................................................. 229 swapf .................................................................... 230 tablrd .................................................................. 231 tablwt .................................................................. 232 tstfsz ................................................................... 233 xorlw ................................................................... 233 xorwf ................................................................... 234 summary table ....................................................... 194 intcon register rbif bit ..................................................................... 80 interrupt sources ....................................................... 65, 181 a/d conversion complete ....................................... 170 capture complete (ccp) ......................................... 111 compare complete (ccp) ....................................... 112 interrupt on change (rb7:rb4 ) ............................... 80 rb0/int pin, external ................................................ 75 ssp receive/transmit complete ............................ 117 tmr0 overflow .......................................................... 95 tmr1 overflow .................................... 97, 99, 105, 107 tmr2 to pr2 match ................................................ 103 tmr2 to pr2 match (pwm) ............................ 102, 115 usart receive/transmit complete ....................... 151 interrupts, enable bits ccp1 enable (ccp1ie bit) ..................................... 111 interrupts, flag bits a/d converter flag (adif bit) ................................. 169 ccp1 flag (ccp1if bit) .................................. 111, 112 interrupt on change (rb7:rb4) flag (rbif bit) ........ 80 iorlw ............................................................................. 214 iorwf ............................................................................. 214 k keeloq evaluation and programming tools ................ 238
7/99 microchip technology inc. preliminary ds39026b-page 289 pic18cxx2 m memory organization data memory ............................................................. 40 program memory ....................................................... 33 movfp ............................................................................ 216 movlb ............................................................................ 215 movlr .................................................................... 215, 216 movlw ........................................................................... 217 movwf ........................................................................... 217 mplab integrated development environment software . 235 mullw ............................................................................ 218 multi-master mode ........................................................... 145 multiply examples 16 x 16 routine .......................................................... 62 16 x 16 signed routine .............................................. 63 8 x 8 routine .............................................................. 62 8 x 8 signed routine .................................................. 62 mulwf ............................................................................ 218 n negw .............................................................................. 219 nop ................................................................................. 219 o opcode field descriptions ............................................ 192 option_reg register ..................................................... 51 ps2:ps0 bits ............................................................. 95 psa bit ....................................................................... 95 t0cs bit ..................................................................... 95 t0se bit ..................................................................... 95 osccon ........................................................................... 18 osccon register ............................................................. 18 oscillator configuration .............................................. 15, 181 hs .............................................................................. 15 lp ............................................................................... 15 rc ........................................................................ 15, 16 xt .............................................................................. 15 oscillator, timer1 ......................................... 97, 99, 105, 107 oscillator, wdt ................................................................ 185 ov ...................................................................................... 54 p packaging ........................................................................ 275 parallel slave port (psp) ............................................. 85, 90 block diagram ............................................................ 90 re0/rd /an5 pin .................................................. 89, 90 re1/wr /an6 pin ................................................. 89, 90 re2/cs /an7 pin .................................................. 89, 90 read waveforms ....................................................... 91 select (pspmode bit) ........................................ 85, 90 timing diagram ........................................................ 259 write waveforms ....................................................... 90 picdem-1 low-cost picmicro demo board ................... 237 picdem-2 low-cost pic16cxx demo board ................ 237 picdem-3 low-cost pic16cxxx demo board .............. 237 picstart plus entry level development system ...... 237 pin functions mclr /vpp ............................................................. 8, 11 osc1/clkin .......................................................... 8, 11 osc2/clkout ...................................................... 8, 11 ra0/an0 ................................................................ 8, 11 ra1/an1 ................................................................ 8, 11 ra2/an2 ................................................................ 8, 11 ra3/an3/vref ........................................................ 8, 11 ra4/t0cki ............................................................. 8, 11 ra5/an4/ss .......................................................... 8, 11 rb0/int ................................................................. 9, 12 rb1 ........................................................................ 9, 12 rb2 ........................................................................ 9, 12 rb3 ........................................................................ 9, 12 rb4 ........................................................................ 9, 12 rb5 ........................................................................ 9, 12 rb6 ........................................................................ 9, 12 rb7 ........................................................................ 9, 12 rc0/t1oso/t1cki ............................................. 10, 13 rc1/t1osi/ccp2 ............................................... 10, 13 rc2/ccp1 ........................................................... 10, 13 rc3/sck/scl ..................................................... 10, 13 rc4/sdi/sda ...................................................... 10, 13 rc5/sdo ............................................................. 10, 13 rc6/tx/ck .......................................................... 10, 13 rc7/rx/dt .......................................................... 10, 13 rd0/psp0 ................................................................. 14 rd1/psp1 ................................................................. 14 rd2/psp2 ................................................................. 14 rd3/psp3 ................................................................. 14 rd4/psp4 ................................................................. 14 rd5/psp5 ................................................................. 14 rd6/psp6 ................................................................. 14 rd7/psp7 ................................................................. 14 re0/rd /an5 ............................................................. 14 re1/wr /an6 ............................................................. 14 re2/cs /an7 .............................................................. 14 vdd ...................................................................... 10, 14 vss ....................................................................... 10, 14 pointer, fsr ...................................................................... 48 porta initialization ................................................................ 77 porta register ........................................................ 77 ra3:ra0 and ra5 port pins ..................................... 78 ra4/t0cki pin .......................................................... 78 trisa register .......................................................... 77 portb initialization ................................................................ 80 portb register ........................................................ 80 rb0/int pin, external ............................................... 75 rb3:rb0 port pins .................................................... 80 rb7:rb4 interrupt on change flag (rbif bit) .......... 80 rb7:rb4 port pins .................................................... 80 trisb register .......................................................... 80 portc block diagram ........................................................... 83 initialization .................................................... 83, 85, 87 portc register ........................................................ 83 rc3/sck/scl pin ................................................... 130 rc7/rx/dt pin ....................................................... 153 trisc register ................................................. 83, 151 portd .............................................................................. 90 block diagram ........................................................... 85 parallel slave port (psp) function ............................ 85 portd register ........................................................ 85 trisd register ......................................................... 85 porte analog port pins .................................................. 89, 90 block diagram ........................................................... 87 porte register ........................................................ 87 psp mode select (pspmode bit) ...................... 85, 90 re0/rd /an5 pin ................................................. 89, 90 re1/wr /an6 pin ................................................ 89, 90 re2/cs /an7 pin ................................................. 89, 90 trise register .......................................................... 87 postscaler, wdt
pic18cxx2 ds39026b-page 290 preliminary 7/99 microchip technology inc. assignment (psa bit) ................................................ 95 rate select (ps2:ps0 bits) ....................................... 95 switching between timer0 and wdt ........................ 95 power-on reset (por) .............................................. 24, 181 oscillator start-up timer (ost) ......................... 24, 181 power-up timer (pwrt) ................................... 24, 181 time-out sequence .................................................... 25 time-out sequence on power-up ........................ 30, 31 timing diagram ........................................................ 256 prescaler, capture ........................................................... 111 prescaler, timer0 ............................................................... 95 assignment (psa bit) ................................................ 95 rate select (ps2:ps0 bits) ....................................... 95 switching between timer0 and wdt ........................ 95 prescaler, timer1 ............................................................... 98 prescaler, timer2 ............................................................. 115 pro mate ii universal programmer ............................ 237 product identification system ........................................... 297 program counter pcl register .............................................................. 37 pclath register ...................................................... 37 program memory ............................................................... 33 interrupt vector .......................................................... 33 reset vector .............................................................. 33 program verification ......................................................... 189 programming, device instructions ................................... 191 pwm (ccp module) ......................................................... 114 block diagram .......................................................... 114 ccpr1h:ccpr1l registers ................................... 115 duty cycle ................................................................ 115 example frequencies/resolutions .......................... 116 output diagram ........................................................ 114 period ....................................................................... 115 set-up for pwm operation ...................................... 116 tmr2 to pr2 match ........................................ 102, 115 q q-clock ............................................................................ 115 r rcsta register spen bit .................................................................. 151 register file ....................................................................... 40 registers sspstat ................................................................. 118 t1con diagram ........................................................... 105 section ............................................................. 105 reset .......................................................................... 23, 181 timing diagram ........................................................ 256 retfie .................................................................... 221, 222 retlw ............................................................................. 222 return .......................................................................... 223 revision history ............................................................... 285 rlcf ................................................................................ 223 rlncf ............................................................................. 224 rrcf ............................................................................... 224 rrncf ............................................................................. 225 s sck .................................................................................. 121 sdi ................................................................................... 121 sdo ................................................................................. 121 seeval evaluation and programming system ............ 238 serial clock, sck ............................................................. 121 serial data in, sdi ........................................................... 121 serial data out, sdo ....................................................... 121 simplified block diagram of on-chip reset circuit ........... 23 slave select synchronization .......................................... 125 slave select, ss .............................................................. 121 sleep ............................................................. 181, 187, 226 software simulator (mplab-sim) ................................... 236 special features of the cpu ................................... 175, 181 special function registers ................................................ 40 spi master mode ............................................................ 124 serial clock .............................................................. 121 serial data in ........................................................... 121 serial data out ........................................................ 121 slave select ............................................................. 121 spi clock .................................................................. 124 spi mode ................................................................. 121 spi master/slave connection .......................................... 123 spi module master/slave connection ......................................... 123 slave mode .............................................................. 125 slave select synchronization .................................. 125 slave synch timnig ................................................. 125 slave timing with cke = 0 ...................................... 126 slave timing with cke = 1 ...................................... 126 ss .................................................................................... 121 ssp .................................................................................. 117 block diagram (spi mode) ...................................... 121 spi mode ................................................................. 121 sspbuf .................................................................. 124 sspcon1 ............................................................... 119 sspcon2 ............................................................... 120 sspsr .................................................................... 124 sspstat ................................................................ 118 tmr2 output for clock shift ............................ 102, 103 ssp module spi master mode ..................................................... 124 spi master./slave connection ................................. 123 spi slave mode ....................................................... 125 sspcon1 ........................................................................ 119 sspcon2 ........................................................................ 120 sspov ............................................................................ 139 sspstat ........................................................................ 118 sspstat register r/w bit ............................................................ 129, 130 sublw ............................................................................ 227 subwf ............................................................ 226, 227, 228 subwfb ......................................................................... 229 swapf ............................................................................ 230 t tablrd ........................................................................... 231 tablwt .......................................................................... 232 timer modules timer1 block diagram ................................................. 106 timer0 ................................................................................ 93 clock source edge select (t0se bit) ....................... 95 clock source select (t0cs bit) ................................. 95 overflow interrupt ...................................................... 95 timing diagram ....................................................... 257 timer1 ........................................................................ 97, 105 block diagram ........................................................... 98 oscillator .............................................. 97, 99, 105, 107 overflow interrupt ................................ 97, 99, 105, 107 special event trigger (ccp) ..................... 99, 107, 112 timing diagram ....................................................... 257 tmr1h register ................................................ 97, 105
7/99 microchip technology inc. preliminary ds39026b-page 291 pic18cxx2 tmr1l register ................................................. 97, 105 timer2 block diagram .......................................................... 103 postscaler. see postscaler, timer2 pr2 register .................................................... 102, 115 prescaler. see prescaler, timer2 ssp clock shift ................................................ 102, 103 tmr2 register ......................................................... 102 tmr2 to pr2 match interrupt .................. 102, 103, 115 timing diagrams acknowledge sequence timing ............................... 142 baud rate generator with clock arbitration ............ 136 brg reset due to sda collision ............................ 147 bus collision start condition timing ..................................... 146 bus collision during a restart condition (case 1) .. 148 bus collision during a restart condition (case2) ... 148 bus collision during a start condition (scl = 0) .... 147 bus collision during a stop condition ..................... 149 bus collision for transmit and acknowledge ........... 145 i 2 c bus data ............................................................ 267 i 2 c master mode first start bit timing ...................... 137 i 2 c master mode reception timing .......................... 141 i 2 c master mode transmission timing ..................... 140 master mode transmit clock arbitration .................. 144 repeat start condition ............................................. 138 slave synchronization ............................................. 125 spi mode timing (master mode)spi mode master mode timing diagram ......................... 124 spi mode timing (slave mode with cke = 0) ......... 126 spi mode timing (slave mode with cke = 1) ......... 126 stop condition receive or transmit ........................ 143 time-out sequence on power-up ........................ 30, 31 usart asynchronous master transmission ........... 158 usart asynchronous reception ............................ 160 usart synchronous reception .............................. 164 usart synchronous transmission ........................ 162 wake-up from sleep via interrupt .......................... 188 timing diagrams and specifications ................................ 253 a/d conversion ........................................................ 271 brown-out reset (bor) ........................................... 256 capture/compare/pwm (ccp) ................................ 258 clkout and i/o ...................................................... 255 external clock .......................................................... 253 i 2 c bus data ............................................................ 265 i 2 c bus start/stop bits ............................................. 264 oscillator start-up timer (ost) ............................... 256 parallel slave port (psp) ......................................... 259 power-up timer (pwrt) ......................................... 256 reset ........................................................................ 256 timer0 and timer1 ................................................... 257 usart synchronous receive ( master/slave) ....... 269 usart synchronoustransmission ( master/slave) 268 watchdog timer (wdt) ........................................... 256 trise register .................................................................. 87 pspmode bit ...................................................... 85, 90 tstfsz ........................................................................... 233 txsta register brgh bit ................................................................. 153 u universal synchronous asynchronous receiver transmitter. see usart usart ............................................................................. 151 asynchronous mode ................................................ 157 master transmission ....................................... 158 receive block diagram ................................... 159 reception ........................................................ 160 transmit block diagram .................................. 157 baud rate generator (brg) ................................... 153 baud rate error, calculating ........................... 153 baud rate formula ......................................... 153 baud rates, asynchronous mode (brgh=0) . 155 baud rates, asynchronous mode (brgh=1) . 156 baud rates, synchronous mode ..................... 154 high baud rate select (brgh bit) ................. 153 sampling ......................................................... 153 serial port enable (spen bit) ................................. 151 synchronous master mode ...................................... 161 reception ........................................................ 164 timing diagram, synchronous receive .......... 269 timing diagram, synchronous transmission .. 268 transmission ................................................... 162 synchronous slave mode ........................................ 165 w wake-up from sleep .............................................. 181, 187 timing diagram ....................................................... 188 watchdog timer (wdt) ........................................... 181, 185 block diagram ......................................................... 186 programming considerations .................................. 185 rc oscillator ........................................................... 185 time-out period ....................................................... 185 timing diagram ....................................................... 256 waveform for general call address sequence ............... 133 wcol .............................................................. 137, 139, 142 wcol status flag ........................................................... 137 www, on-line support ...................................................... 4 x xorlw ........................................................................... 233 xorwf ........................................................................... 234 z z ........................................................................................ 54
pic18cxx2 ds39026b-page 292 preliminary 7/99 microchip technology inc.
7/99 microchip technology inc. preliminary ds39026b-page 293 pic18cxx2 systems information and upgrade hot line the systems information and upgrade line provides system users a listing of the latest versions of all of microchip's development systems software products. plus, this line provides information on how customers can receive any currently available upgrade kits.the hot line numbers are: 1- 800-755-2345 for u.s. and most of canada, and 1- 602-786-7302 for the rest of the world. trademarks: the microchip name, logo, pic, picmicro, picstart, picmaster and pro mate are registered trademarks of microchip technology incorporated in the u.s.a. and other countries. flex rom, mplab and fuzzy- lab are trademarks and sqtp is a service mark of micro- chip in the u.s.a. all other trademarks mentioned herein are the property of their respective companies. on-line support microchip provides on-line support on the microchip world wide web (www) site. the web site is used by microchip as a means to make files and information easily available to customers. to view the site, the user must have access to the internet and a web browser, such as netscape or microsoft explorer. files are also available for ftp download from our ftp site. connecting to the microchip internet web site the microchip web site is available by using your favorite internet browser to attach to: www.microchip.com the file transfer site is available by using an ftp ser- vice to connect to: ftp://ftp.microchip.com the web site and file transfer site provide a variety of services. users may download files for the latest development tools, data sheets, application notes, user's guides, articles and sample programs. a vari- ety of microchip specific business information is also available, including listings of microchip sales offices, distributors and factory representatives. other data available for consideration is: ? latest microchip press releases ? technical support section with frequently asked questions ? design tips ?device errata ? job postings ? microchip consultant program member listing ? links to other useful web sites related to microchip products ? conferences for products, development sys- tems, technical information and more ? listing of seminars and events 981103
pic18cxx2 ds39026b-page 294 preliminary 7/99 microchip technology inc. reader response it is our intention to provide you with the best documentation possible to ensure successful use of your microchip prod- uct. if you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please fax your comments to the technical publications manager at (602) 786-7578. please list the following information, and use this outline to provide us with your comments about this data sheet. 1. what are the best features of this document? 2. how does this document meet your hardware and software development needs? 3. do you find the organization of this data sheet easy to follow? if not, why? 4. what additions to the data sheet do you think would enhance the structure and subject? 5. what deletions from the data sheet could be made without affecting the overall usefulness? 6. is there any incorrect or misleading information (what and where)? 7. how would you improve this document? 8. how would you improve our software, systems, and silicon products? to : technical publications manager re: reader response total pages sent from: name company address city / state / zip / country telephone: (_______) _________ - _________ application (optional): would you like a reply? y n device: questions: fax: (______) _________ - _________ ds39026b pic18cxx2 literature number:
1999 microchip technology inc. preliminary ds39026b-page 295 pic18cxx2 pic18cxx2 product identification system to order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. sales and support part no. - x /xx xxx pattern package temperature range device device pic18cxx2 ( 1 ) , pic18cxx2t ( 2 ); v dd range 4.2v to 5.5v pic18lcxx2 ( 1 ) , pic18lcxx2t ( 2 ); v dd range 2.5v to 5.5v temperature range i= -40 c to+85 c(industrial) e= -40 c to+125c(extended) package jw = windowed cerdip ( 3 ) pt = tqfp (thin quad flatpack) so = soic sp = skinny plastic dip p=pdip l=plcc pattern qtp, sqtp, code or special requirements (blank otherwise) examples: a) pic18lc452 - i/p 301 = industrial temp., pdip package, 4 mhz, extended v dd limits, qtp pattern #301. b) pic18lc242 - i/so = industrial temp., soic package, extended v dd limits. c) pic18c442 - e/p = extended temp., pdip package, 40mhz, normal v dd limits. note1: c = standard voltage range lc = wide voltage range 2: t = in tape and reel - soic, plcc, and tqfp packages only. 3: jw devices are uv erasable and can be programmed to any device configuration. jw devices meet the electrical requirement of each oscillator type (including lc devices). data sheets products supported by a preliminary data sheet may have an errata sheet describing minor operational differences and recom- mended workarounds. to determine if an errata sheet exists for a particular device, please contact one of the following: 1. your local microchip sales office 2. the microchip corporate literature center u.s. fax: (602) 786-7277 3. the microchip worldwide site (www.microchip.com) please specify which device, revision of silicon and data sheet (include literature #) you are using. new customer notification system register on our web site (www.microchip.com/cn) to receive the most current information on our products.
information contained in this publication regarding device applications and the like is intended for suggestion only and may be superseded by updates. no representation or warranty is given and no liability is assumed by microchip technology incorporated with respect to the accuracy or use of such information, or infringement of patents or oth er intellectual property rights arising from such use or otherwise. use of microchip?s products as critical components in life support systems is not authorized except with express written approval by microchip. no licenses are conveyed, implicitly or otherwise, under any intellectual property rights. the microchip logo and name are registered trademarks of microchip technology inc. in the u.s.a. and other countries. all rights reserved. al l other trademarks mentioned herein are the property of their respective companies. ? 1999 microchip technology inc. all rights reserved. ? 1999 microchip technology incorporated. printed in the usa. 11/99 printed on recycled paper. americas corporate office microchip technology inc. 2355 west chandler blvd. chandler, az 85224-6199 tel: 480-786-7200 fax: 480-786-7277 technical support: 480-786-7627 web address: http://www.microchip.com atlanta microchip technology inc. 500 sugar mill road, suite 200b atlanta, ga 30350 tel: 770-640-0034 fax: 770-640-0307 boston microchip technology inc. 5 mount royal avenue marlborough, ma 01752 tel: 508-480-9990 fax: 508-480-8575 chicago microchip technology inc. 333 pierce road, suite 180 itasca, il 60143 tel: 630-285-0071 fax: 630-285-0075 dallas microchip technology inc. 4570 westgrove drive, suite 160 addison, tx 75248 tel: 972-818-7423 fax: 972-818-2924 dayton microchip technology inc. two prestige place, suite 150 miamisburg, oh 45342 tel: 937-291-1654 fax: 937-291-9175 detroit microchip technology inc. tri-atria office building 32255 northwestern highway, suite 190 farmington hills, mi 48334 tel: 248-538-2250 fax: 248-538-2260 los angeles microchip technology inc. 18201 von karman, suite 1090 irvine, ca 92612 tel: 949-263-1888 fax: 949-263-1338 new york microchip technology inc. 150 motor parkway, suite 202 hauppauge, ny 11788 tel: 631-273-5305 fax: 631-273-5335 san jose microchip technology inc. 2107 north first street, suite 590 san jose, ca 95131 tel: 408-436-7950 fax: 408-436-7955 americas (continued) toronto microchip technology inc. 5925 airport road, suite 200 mississauga, ontario l4v 1w1, canada tel: 905-405-6279 fax: 905-405-6253 asia/pacific hong kong microchip asia pacific unit 2101, tower 2 metroplaza 223 hing fong road kwai fong, n.t., hong kong tel: 852-2-401-1200 fax: 852-2-401-3431 beijing microchip technology, beijing unit 915, 6 chaoyangmen bei dajie dong erhuan road, dongcheng district new china hong kong manhattan building beijing 100027 prc tel: 86-10-85282100 fax: 86-10-85282104 india microchip technology inc. india liaison office no. 6, legacy, convent road bangalore 560 025, india tel: 91-80-229-0061 fax: 91-80-229-0062 japan microchip technology intl. inc. benex s-1 6f 3-18-20, shinyokohama kohoku-ku, yokohama-shi kanagawa 222-0033 japan tel: 81-45-471- 6166 fax: 81-45-471-6122 korea microchip technology korea 168-1, youngbo bldg. 3 floor samsung-dong, kangnam-ku seoul, korea tel: 82-2-554-7200 fax: 82-2-558-5934 shanghai microchip technology rm 406 shanghai golden bridge bldg. 2077 yan?an road west, hong qiao district shanghai, prc 200335 tel: 86-21-6275-5700 fax: 86 21-6275-5060 asia/pacific (continued) singapore microchip technology singapore pte ltd. 200 middle road #07-02 prime centre singapore 188980 tel: 65-334-8870 fax: 65-334-8850 taiwan, r.o.c microchip technology taiwan 10f-1c 207 tung hua north road ta i p e i , ta i wa n , ro c tel: 886-2-2717-7175 fax: 886-2-2545-0139 europe united kingdom arizona microchip technology ltd. 505 eskdale road winnersh triangle wokingham berkshire, england rg41 5tu tel: 44 118 921 5858 fax: 44-118 921-5835 denmark microchip technology denmark aps regus business centre lautrup hoj 1-3 ballerup dk-2750 denmark tel: 45 4420 9895 fax: 45 4420 9910 france arizona microchip technology sarl parc d?activite du moulin de massy 43 rue du saule trapu batiment a - ler etage 91300 massy, france tel: 33-1-69-53-63-20 fax: 33-1-69-30-90-79 germany arizona microchip technology gmbh gustav-heinemann-ring 125 d-81739 mnchen, germany tel: 49-89-627-144 0 fax: 49-89-627-144-44 italy arizona microchip technology srl centro direzionale colleoni palazzo taurus 1 v. le colleoni 1 20041 agrate brianza milan, italy tel: 39-039-65791-1 fax: 39-039-6899883 11/15/99 w orldwide s ales and s ervice microchip received qs-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona in july 1999. the company?s quality system processes and procedures are qs-9000 compliant for its picmicro ? 8-bit mcus, k ee l oq ? code hopping devices, serial eeproms and microperipheral products. in addition, microchip ? s quality system for the design and manufacture of development systems is iso 9001 certified.

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