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STV0681
DUAL-MODE DIGITAL CAMERA CO-PROCESSOR
DESCRIPTION STMicroelectronics Imaging Division has produced the camera co-processor STV0681 which, used with CIF/VGA sensors as part of a low cost dualmode camera chipset, allows a new line of low cost cameras or toy products to be brought to the market. STV0681 is a mask ROM version of STV0680B, programmed with v3.00 Firmware. FEATURES ST have maintained the standard features already available in the successful STV068B chipset, including:
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Quick Power Down (by holding Mode Button). "Delete Last" Function
Audio Record and Playback The enhanced features included in STV0681 allow audio memos to be recorded at a sampling rate of 11kHz, by adding a microphone and comparator chip, and by utilizing the pre-amplifier included in CIF/VGA sensors such as VV6411 and VV6501 respectively. These sounds can be uploaded to the PC over USB or RS232, and played back using a Software application developed by the OEM using the SDK. Demonstration PC software with source code is available with the Evaluation Kit (EVK). With suitable OEM software, the camera could even be used to record comments about pictures or video clips in a "dictaphone" fashion, with the audio commentary played back when viewing the pictures/video. Recorded audio sounds can also be played back on the camera, with the addition of an amplifier chip and speaker or headphone socket. By auto-detecting hardware, STV0681 will only enable these additional functions if audio hardware is fitted. Actual hardware implementation is the subject of a separate STV0681 Reference design (see Chapter 10). Evaluation Kit and Reference Design Evaluation kits are available for STV0681 features. Precise design guidelines are available from ST as a reference design manual (see Chapter 10).
Support for VV6411 (CIF) and VV6501 (VGA) CMOS imaging sensors. Support for SDRAM sizes 16MBit (up to 20 CIF images) or 64Mbit (up to 80 CIF or 26 VGA images). Low resolution "economy" mode allows for more images to be stored. High frame rate web cam (tethered video) over USB. Audio record/playback and "Delete Last" function Custom sounds playback (e.g. "Talking" or "Musical" camera) Support for an OEM Flashgun module Automatic anti-flicker exposure control. Image up load over RS232 or USB. Driver support for Win98/Win2k/WinME and MacOS 8.6/9.0/9.1. Continuous capture while untethered (except when Flashgun enabled) and downloading to AVI file format Power-saving "stand-by" mode which maintains memory contents. Simple user interface including 2 buttons, status LCD display, and buzzer. Evaluation Kit (EVK) available. Software Development Kit (SDK) allows OEM PC Software applications to be written.
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Simultaneous audio record and continuous video capture is not possible.
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Table of Contents
Chapter 1
1.1 1.2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Digital camera chipset .......................................................................................................... 5 Key system features ............................................................................................................. 6
Chapter 2
2.1 2.2 2.3 2.4 2.5 2.6
Detailed Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Sensor type and image formats ........................................................................................... 9 User interface ..................................................................................................................... 10 Battery level detect and USB auto-switch .......................................................................... 12 Audio record and playback ................................................................................................. 12 PC interface options and software support ........................................................................ 13 Anti-flicker exposure and gain control ................................................................................ 14
Chapter 3
3.1 3.2
Camera Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Modes available ................................................................................................................. 15 Description of modes ......................................................................................................... 16
Chapter 4
4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10
STV0681 Hardware Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Sensor interface ................................................................................................................. 18 Memory interface ............................................................................................................... 18 USB interface ..................................................................................................................... 21 UART module for RS232 interface ..................................................................................... 22 Power management and battery type ................................................................................ 23 Quartz crystal ..................................................................................................................... 24 Numeric LCD interface ....................................................................................................... 24 Switches and LED's ........................................................................................................... 25 Flashgun hardware interface .............................................................................................. 26 IR filter ................................................................................................................................ 26
Chapter 5
5.1 5.2 5.3
Customising the STV0681 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
External EEPROM ............................................................................................................. 27 EEPROM data format ........................................................................................................ 28 Programming the EEPROM ............................................................................................... 28
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6.1 6.2
Software support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
General features ................................................................................................................ 29 Software installation ........................................................................................................... 30
Chapter 7
7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8
Detailed Chipset Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Typical camera specifications ............................................................................................ 31 Absolute maximum ratings ................................................................................................. 31 STV0681 specifications ...................................................................................................... 32 USB specifications ............................................................................................................. 32 DC characteristics .............................................................................................................. 33 PLL characteristics ............................................................................................................. 33 Crystal tolerance ................................................................................................................ 33 Typical current consumption of complete camera .............................................................. 34
Chapter 8
8.1 8.2
STV0681 pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
STV0681 pinout ................................................................................................................. 35 STV0681 pin description .................................................................................................... 36
Chapter 9 Chapter 10
10.1 10.2
STV0681 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 Evaluation Kit (EVK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Ordering details .................................................................................................................. 42 Technical support ............................................................................................................... 43
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Document Revision History
Revision
A B
Draft
1.0 4.0
Date
May 2001 April 2002
Comments
Initial release (product preview) Document status updated to datasheet. Major changes: removed references of VV6410 and VV6444 sensors Removed all salestypes for imaging sensors: removed section 6.1 addition of chapter 5 - Customizing the STV0681 Replacement of section 6.1 - General features (in Chapter 6 Software support)
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Introduction
1
1.1
1.1.1
Introduction
Digital camera chipset
General
This document describes the features and functionality of a CMOS chipset, comprising an STMicroelectronics (ST) CIF or VGA resolution sensor and an STV0681 companion processor, as well as outlining what peripheral components are required/supported in order to complete a camera using the chipset. Such a camera is particularly suited to dual-mode digital stills or toy applications.
1.1.2
Stills capture and image upload
In stills mode, the camera stores raw image data in memory. The camera features no colour processing, ensuring its simplicity and low cost. Subsequent upload of raw data to a PC or Macintosh for processing is done through an RS232 or USB interface, through demo software, a TWAIN driver, or OEM custom application. The license to use the colour algorithm (embedded in the PC or Mac driver software) is included in the price of the chipset.
1.1.3
Webcam Video over USB
A video option is provided, when tethered through USB. It allows for Video for Microsoft WindowsTM applications, and `video clips' to be recorded while untethered by continuously capturing images in `continuous' mode. Images are then downloaded to the PC for playback, using software to create an AVI file.
1.1.4
Audio features
The STV0681 allows audio memos to be recorded at a sampling rate of 11kHz. These sounds can be uploaded to the PC over USB or RS232 and played on the PC, or they can be replayed on the camera. With audio playback hardware fitted to the camera, it is possible to download a set of up to 20.WAV file "sound bites", to store in SDRAM, each of which can be linked to a particular camera function. This allows for camera "Theme Music", custom sounds such as an imitation shutter "Click-Whirr", or for certain functions to "talk" to the user, e.g. "Nice picture!". This has limitless possibilities for OEM language customizing or licensed character cameras. Downloading sounds is possible with the use of an OEM application developed using the SDK, and a demonstration PC application with source code is available with the EVK. Sounds are stored in SDRAM and will therefore reduce the number of images/amount of audio which can be stored, STV0681 calculates the remaining memory and displays the number of images left. Sounds can only be stored when untethered while battery power is maintained.
1.1.5
Flashgun support
The addition of an OEM flashgun module increases the camera capabilities and improves low light image quality. STV0681 flashgun support includes modified exposure control, an enable input and a correctly timed trigger output. Although it remains the responsibility of the OEM to source a suitable Flashgun module, advice on hardware interfacing, flash charge sensing and required flashgun energy are given in a separate Flashgun Application Note (AN1312), please contact ST for details.
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Introduction 1.1.6 "Delete Last" function
STV0681
An additional user interface function is available in STV0681 with either audio record or playback hardware fitted. With these, the user can delete the last image or continuous clip to be captured, or the last audio memo to be recorded. The standard "Clear all" ("CL") function remains, whether or not audio hardware is fitted.
1.1.7
Backward compatibility with STV0680B
STV0681 is electrically and functionally compatible with cameras designed for STV0680B, and uses the same PC/Mac drivers, however the change of device pinout means that some PCB re-design will be required. Precise design guidelines are available from ST as a reference design (see Chapter 10). A software development kit (SDK) for PC is available from ST to interface to the camera and provide the basis to develop a custom software application for stills and/or video. It includes colour processing software.
Figure 1: Typical camera system block diagram
Audio
Speaker Amplifier
LED
Push Buttons:
"Shutter /Record"
Flashgun Enable/Trigger
2 x 7 seg. LCD
"Mode"
CMOS Sensor OEM Flashgun Module
VV6411 (CIF) VV6501 (VGA)
Microphone
Comparator
Enable/Trigger
Audio Pre-Amp
GPIO Audio DAC
Sensor data
LCD memory Driver I/F RS232 I/F
STV0681
16MBit or 64MBit SDRAM
Transceiver Circuit (Discretes) Power Management Circuit (Discretes)
Sensor clock
Image Array
Sensor I/F PWM 12MHz XTAL
RS232 interface to PC USB interface to PC
4.5 - 6v Battery e.g. 3-4 x AA, AAA, etc.
USB I/F
Detect Low Battery
Piezo Buzzer
Subject
Lens + IR Filter
VReg
3v3 supply 4-5v (Nominal) supply from Battery or USB
1.2
Key system features
The key features of a typical camera based on the STV0681 chipset are listed here below.
1.2.1
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Image features
Support for CIF resolution sensor - 352 x 288 pixels Support for VGA resolution sensor - 640 x 480 pixels 80 picture storage capacity possible for CIF, with 64MB memory 26 picture storage capacity for VGA, with 64MBit memory A greater number of images can be stored when `Low' resolution mode is enabled (e.g. 80 QCIF images with 16Mbit memory, 107 QVGA images with 64Mbit memory). See Table 1. Automatic anti-flicker exposure and gain control Support for flashgun.
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Introduction
User features on camera
Self-timer mode allows a picture to be captured after several seconds. Twin 7 segment LCD panel supported - showing number of pictures left, and modes. Picture counter helps the user to know how much memory is left. Un-tethered `Continuous' mode allows capture of image sequences for storage in memory and subsequent download to PC. Piezo buzzer indicates a number of useful events to the user, e.g. whether enough light is present for picture capture, etc. LED indicator . "Clear all" function clears camera. "Low Resolution" mode increases number of images which can be captured by reducing image resolution. Audio Record function (if audio record hardware detected) allows sounds to be recorded. Audio Playback function (if audio playback hardware fitted) allows sounds which have been recorded to be played back. "Delete last" function allows user to delete audio memos, pictures or continuous clips, deletion must be carried out "most reset first". Camera can be configured by the user to play custom sounds at certain functions, using a PC application. "Go to sleep" function, whereby the camera can be put into standby mode while untethered.
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User features on PC software
PC software allows a number of features such as fast download of thumbnail images for picture selection, and automatic detection and correction of sensor defects. The driver compatibility includes:
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TWAIN driver to suit all TWAIN compatible imaging applications Video for Microsoft WindowsTM PC driver for tethered video mode (through USB), available at all resolutions, with fastest framerates at QCIF resolution AVI video file creation from image sequences captured in `continuous' mode Quicktime Video driver and Adobe Photoshop stills plug-in for Mac Custom OEM PC software can be developed by using the SDK (for SDK availability, contact ST), to upload thumbnails/still images or `continuous' images, e.g. for AVI file creation. The SDK (version 2.90 or later) allows: the OEM to write a custom application and upload sound memos based on the example LCDC demo software. the OEM to write a custom application and download custom sounds to the camera based on the example CustomSound software.
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Power management features and USB compliance
Retention of pictures, recorded sounds and downloaded custom sounds with extremely low power operation. The camera seems to be "switched off". Auto power-off after 30 seconds of non usage. Operates from 4.5-6V battery, although system voltage is 5V or 3.3V, dependant on sensor. Low battery detection.
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Introduction
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STV0681
Dependant on hardware configuration, switch-over to USB power supply is supported and the device can operate with low batteries or without batteries when connected to USB. Full USB compliance requirements are listed in the USB specification. However, in a camera designed using this chipset, the following must at least be included: (a) an SDRAM with sufficiently low selfrefresh current, (b) USB inrush protection circuitry to maintain sufficient supply voltage to the 5V sensor. See Section 7 for further details.
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General features
High speed picture/sounds upload to PC/Mac over USB ST colour processing algorithms included under license (as part of drivers/SDK) USB or RS232 serial interface options, and VfW / TWAIN driver support.
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Detailed Features
2
2.1
Detailed Features
Sensor type and image formats
The sensor type is auto-detected by STV0681, the correct sensor timing is enabled and the correct image resolutions are enabled, as shown in Table 1. For stills photography, `High' or `Low' resolution mode can be selected, to give CIF or QCIF pictures from a CIF sensor, and VGA or QVGA from a VGA sensor (see Table 1). Reduced resolution allows for storage of more images. Images captured in both `High' and `Low' resolution can be stored in camera memory at the same time. Therefore there is no need to clear images stored in memory prior to changing image resolution. Where USB is connected, the host PC software (through a Video for Microsoft WindowsTM driver) can activate tethered video mode, regardless of the user inputs to the camera buttons. In this case, the image resolution is controlled by the PC driver.
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When tethered VfW video (PC) or Quicktime driver (Mac) is activated, all images or recorded sounds or video clips are deleted from the camera SDRAM. A software solution is available ("Camera control", as part of the SDK for PC, and "Plug'n Save" for Mac) which can monitor whether a camera is connected and warns the user if activating the VfW driver causes SDRAM contents to be deleted.
Table 1: Image modes supported Max. no. of images Resolution stored in Final Image Size mode 16MBit memory (Note 2)
High Low CIF 352 x 288 QCIF 176 x 144 (Subsampled) VGA 640 x 480 High Low VGA 640 x 480 QVGA 320 x 240 (Subsampled) (6) (26) 20 80
Sensor Image Size
Max. no. of images stored in 64MBit memory (Note 2)
80 322 (see Note 3) 26 107 (see Note 3)
Approximate VfW framerate (Note 1)
CIF 352 x 288
15 frames/sec. 22.5 frames/sec.
2 frames/sec. 12 frames/sec.
Note: 1 VfW framerate is dependent on PC performance and USB bus loading 2 The number of images which can be stored is reduced if Audio sounds have been recorded on the camera or if custom sounds have been downloaded from the PC to the camera. The reduction of capacity depends on the length of audio clip, but a rough guide is that if 1 CIF image uses the same amount of SDRAM as 10sec of audio, and one VGA image uses the same amount of SDRAM as 30 sec. of audio. 3 A CIF camera with STV0681 and 64Mbit SDRAM can store up to 320 images by using QCIF mode. When more than 99 images are available, the LCD display remains at 99. When the number of available images is inferior to 99, the LCD display shows the number of available images like in all other modes.
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Detailed Features 2.1.1 IR filter
STV0681
For IR filter design, the best choice filter follows the GS0034 dielectric stack filter specification available from STMicroelectronics. An alternative, although not optimal filter, would be Schott S8612 doped glass also sold as CM500.
2.2
User interface
The user interface supported by STV0681 comprises of user controls, buzzer sounds or customized sounds and visual displays.
2.2.1
Push buttons
The following are the functions which are supported by the chipset. These functions are achievable with no more than 2 push buttons. 1 Mode button (wake-up/switch between modes) This button allows the user (1.1) to wake the camera up from standby mode when the camera is to be used for taking pictures, or (1.2) to switch between modes of operation shown in Chapter 3. Shutter button (shutter/confirm action) This button allows the user to take a picture or confirm an action, as shown in Chapter 3
2
The modes of operation are described in Chapter 3. It may also be desirable to include an on-off slider switch. The advantages and disadvantages as well as its exact function are discussed in the reference design available from STMicroelectronics. When a flashgun module is included in the camera, it is necessary to include a flash on/flash off push button or slider switch depending on the exact flashgun module design. Possible implementations are discussed in a separate application note AN1312 available from STMicroelectronics.
2.2.2
LED indicator
The LED indicator displays the camera status when not in Standby/PC suspend mode.
2.2.3
Picture counter using 2 x 7 segment display
STV0681 stores a picture counter value indicating how many images can still be captured. STV0681 supports a 2x7 segment LCD panel. In `Snapshot' mode and continuous capture mode, this LCD panel displays the number of pictures still available. This is useful to identify when the user is approaching the maximum number of images which can be stored (see Table 1). The user can clear the images stored in memory and continue taking pictures. In other modes, this LCD panel displays a 2-character code that helps the user to navigate around the modes.
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A CIF camera with STV0681 and 64Mbit SDRAM can store up to 320 images by using QCIF mode. When more than 99 images are still available, the LCD display remains at 99. When the number of available images is inferior to 99, the LCD display shows how many images are available like in all other modes.
For suitable numeric LCD panel types, see Section 4.7.
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Detailed Features
An on-chip pulse width modulator (PWM) generates buzzer sounds to signal certain events. The distinctive sounds are characteristic of the type of events indicated by the buzzer, as described here below. 1 2 3 4 Camera has been `Woken up' from standby mode (either by the user pressing a button, by reconnecting the power source, or by connecting a USB/RS232 connection). Camera has `gone to sleep' that is moved into standby mode. Pictures are retained in memory. Picture was taken successfully once the user had pressed the capture button. Picture has NOT been taken when the user pressed the capture button because of insufficient light, or because the exposure control was not ready following a rapid change of lighting in the scene. Picture has NOT been taken when the user pressed the capture button because the picture counter had reached the maximum number of images. The user has the chance to reset the counter if desired. End of continuous capture in un-tethered `Continuous' mode due to full memory. Self-timer activated, count down has started.
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2.2.5
Custom sounds
A camera which includes STV0681 and audio playback hardware can have a set of custom sounds downloaded from a PC application. A different sound can be associated with each of the following functions:
Table 2: List of custom sound functions
Power On Power Off Good picture Bad picture (Normally due to insufficient light) Memory full Self timer #1 Self timer #2 Low resolution High resolution Picture delete Sound delete Continuous clip delete Clear memory Confirm action Low power Flashgun ON Flashgun OFF Flashgun Trigger
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Detailed Features
Table 2: List of custom sound functions
Frequency 50kHz Frequency 60kHz
STV0681
Note: 1 When a sound is associated to a given function, and it is stored in SDRAM, the piezo buzzer does not give any beeps for that function. Not all functions need to have custom sounds associated with them, this is the choice of the user or OEM. 2 A demonstration PC application "CustomSounds" is available from ST, however this is not intended for end-users. Source code is available which allows the OEM to build their own PC application using the SDK.
2.3
Battery level detect and USB auto-switch
An on-chip battery level detector on STV0681 detects when the battery voltage falls below a threshold. The chosen threshold level is determined by a resistor value, as shown in Chapter 7. Where no USB has been detected, the LCD display flashes, indicating that the battery is low. When a USB connection has been detected, the LCD display does not flash.
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It may be a requirement of certain USB compliance tests that such additional hardware is included in the camera design, in order to enable the camera to switch to supply from USB and hence report back to the PC while connected to the USB bus without a battery.
2.4
2.4.1
Audio record and playback
Record
A camera including the STV0681 with a microphone, a comparator and other periphery (also using the sensor pre-amplifier) can record sounds stored like images. STV0681 auto-detects the presence of audio record hardware and includes audio record and "delete last" functions into the user interface. The audio sample rate is 11.025 kHz, the signal is digitized using a successive approximation A-D converter with 8 bits resolution. The SDRAM stores 1 second of audio recording per 11 kByte of memory.
2.4.2
Playback
A camera including the STV0681 with an amplifier, a speaker/headphone socket and other periphery can playback sounds either recorded on the camera or downloaded from the PC. The quality of audio playback is largely dependant on the type of speaker used, and on the correct mounting of the speaker in the camera plastics.
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Detailed Features
2.5
PC interface options and software support
USB interface (full speed 12Mbit per second maximum) and RS232 interface (115.2kbaud) are supported by the chipset, with driver software available from STMicroelectronics for both. The interface type is auto-detected by the chipset. PC software can be one of the following: 1 2 3 4 Simple image upload demonstration software supplied by ST, allowing uploading of stills or `continuous' images. This software should not be supplied as an end-user product. TWAIN driver to suit all TWAIN compatible imaging applications, Video for Microsoft WindowsTM driver for tethered video mode (USB only), Custom end-user software developed by OEM using SDK (for SDK availability, contact ST). The SDK is supplied by ST as a 32-bit DLL format, running on Microsoft WindowsTM 98, and accessed through a documented software interface. This provides the basis for developing a custom software application for uploading stills and/or video.
2.5.1
USB
Complete images (displayed as either thumbnails or in full resolution), or the entire SDRAM contents (e.g. for uploading continuously captured image sequences, recorded using `Continuous Capture' mode) can be downloaded through USB, and USB connection also allows for tethered video mode to be activated by the USB driver. Thumbnail image download is extremely fast for the entire memory contents in the camera. Once a picture is selected for download, full image download takes approximately 0.15 second per image for a CIF image (0.6 second for a VGA image), plus post processing time per image. For USB interface details, see Section 4.3.
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Actual USB download and post processing time also depends on PC performance and USB bus loading
2.5.2
RS232
Thumbnails of images, complete stored images, or the entire SDRAM contents can be downloaded through RS232, but tethered video is not supported. Once a picture is selected for download, full image download takes approximately 10 seconds per image for a CIF image (around 30 seconds for a VGA image), plus post processing time per image (of the order of 1 second approximately). For RS232 interface details, see Section 4.4.
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Actual post processing time after RS232 download also depends on PC performance
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Detailed Features
STV0681
2.6
2.6.1
Anti-flicker exposure and gain control
General
The chipset operates automatic exposure and gain control for either 50Hz or 60Hz mains-driven indoor lighting, using the same 12MHz crystal. This improves picture quality by selecting a set of exposure values which minimize `flicker' effects. Detection of the mains frequency is dependant on the status of the GPIO3 pin, which can be achieved by population of a PCB link at a late stage in production, once the country of destination is known, without the need to change the crystal frequency. The auto exposure and gain algorithm is always enabled during Snapshot'/self-timer/continuous mode. When the shutter button is pressed in `Snapshot' mode, the chipset captures an image if the exposure and gain values are suitable for the current scene. If the light has suddenly changed, the camera may emit an audible tone to indicate that more time is required to reach the correct exposure target. In `Snapshot' mode the chipset only captures the image data if sufficient light is present in the image. In continuous capture mode, the chipset captures images regardless of whether enough light is present. The exposure control algorithm in STV0681 chooses exposure values which minimize "flicker" effects from occurring under fluorescent lighting. STV0681 can only prevent flicker in lighting powered by 50Hz or 60Hz electricity supply, but automatic detection of the flicker frequency is not possible. Hence choosing the correct anti-flicker setting is important, in order to prevent dark stripes from appearing across the image, and this selection must be done in hardware.
Figure 2: Illustration of flicker problem
Flicker setting not correct
Flicker setting correct
2.6.2
Flashgun exposure
When the STV0681 and a flashgun module are included in the camera, and the flashgun enable signal is high, the exposure mode operates in a different manner. The CMOS sensor progressive scan readout requires that the sensor is set to maximum exposure so that all lines are exposed. The flashgun operates during a few 100 s in order to correctly expose all sensor lines, (contact ST for more precise details), therefore the flashgun module design should have reached maximum light output within this period after the falling edge of the flash trigger output from STV0681. Possible flashgun implementations, regarding hardware interface, charge sensing, and flash energy required are discussed in a separate application note AN1312 available from STMicroelectronics.
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Camera Modes of Operation
3
Camera Modes of Operation
This section refers to the two switches as discussed in section Section 2.2.1
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"Mode": connects GPIO0 pin of STV0681 to GND when pressed "Shutter": connects GPIO1 pin of STV0681 to GND when pressed Pressing the mode switch repeatedly cycles through a series of modes as displayed on the LCD. When a given mode is displayed it may be selected by pressing the shutter button. If an option is not selected within 5 seconds, the display reverts to showing the number of available pictures.
3.1
Modes available
Figure 3: STV0681 modes (CIF camera with 16Mbit SDRAM assumed)
Press Mode button Normal: 20 / 80 After 30sec of inactivity Audio Record: Ar Notes: Audio Playback: AP 1. Audio Record only available if audio hardware is fitted 2. Audio Playback only available once an audio clip has been recorded Delete Last: dA / dP / dC 3. Delete Last displays (only available if audio hardware fitted) dA - if the last object is an audio clip dP - if the last object is a picture dC - if the last object is a continuous capture clip The mode is inhibited if the camera is empty. 4. Continuous Capture mode is inhibited when the flashgun is enabled (SW6 down) Standby mode (untethered)
Continuous Capture: Ct
Self-Timer: St
Clear All: CL
Resolution: Hr / Lr
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Camera Modes of Operation
STV0681
3.2
3.2.1
Description of modes
Standby mode (untethered) and Wake-up
On power-up, or wake-up from untethered standby mode, (i.e. by pressing the Mode button), the camera beeps twice. The LCD briefly indicates the camera resolution either `Hr.' for high resolution (80 CIF or 26 VGA images - using 64Mbit memory) or `Lr' for low resolution (322 QCIF or 107 VGA images - using 64Mbit memory) and then displays the number of pictures which may be taken. Please note that in low resolution mode, although there can be up to 322 images available, the LCD counter only goes up to 99, it reports 99 until there are less than 99 images left. The camera goes back to standby mode after 30 seconds of inactivity, LED1 turns off and the LCD goes blank. This is also achieved by pressing the mode switch during more than 2 seconds.
3.2.2
Normal mode
Press the shutter button to take a picture. The camera beeps. A high pitched beep indicates that the picture was taken successfully and the counter decrements (if there are less than 99 images left to take). A low beep indicates insufficient light to take a picture. A series of beeps indicates that the camera is full. Stored pictures can be uploaded to a PC at any time, whether or not the camera is full. Plugging the USB connector into the camera causes it to reset and issues a double beep but all stored pictures remain. When the USB connector is unplugged the camera goes to sleep. When connected to the PC, the camera can still be used in the normal way.
Note:
When flashgun is enabled, the camera always takes a picture, with or without sufficient light.
3.2.3
Audio record - Ar
This mode is available with audio record hardware fitted. Pressing the shutter button within 5 seconds causes the camera to start recording for as long as the shutter button is pressed down. If the shutter button is not pressed within 5 seconds, the camera reverts to normal picture taking mode. Whilst recording, the LCD display flashes `Ar'. If the recording stops because the memory is full, the `memory full' audio tone is sounded and the display stops flashing and displays `00'. The audio data is digitized and stored in SDRAM.
3.2.4
Audio Playback - AP
This mode is available with audio playback hardware fitted. Pressing the shutter button within 5 seconds causes the camera to play back the most recent audio recording. If the shutter button is not pressed within 5 seconds the camera reverts to normal picture taking mode. Whilst playing, the LCD display flashes `AP'. Once in Audio Playback mode, repeated presses of the shutter button steps the camera through each of the audio recordings in the camera (most recent first). Keeping the shutter button pressed down also allows to cycle through the audio recordings. Pressing the mode button during playback stops the audio clip.
Note:
Minimum audio recording length is set to 0.5 seconds.
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STV0681 3.2.5 Delete Last Object - dA/dP/dC
This mode is available with audio record hardware fitted.
Camera Modes of Operation
If the last object captured was an audio recording, 'dA' (delete audio) is displayed, if the last object was an image, then 'dP' (delete picture) is displayed, or, if the last object was part of a continuous capture sequence, then 'dC' (delete continuous) is displayed. If the camera is empty, the mode is suppressed. The mode works like `CL' (Clear All), that is once the mode is selected, pressing the shutter button once causes the camera to beep and `dA', `dP' or `dC' to start flashing. Pressing the shutter button again within 5 seconds deletes the last audio clip, picture or continuous capture sequence.
3.2.6
Continuous mode - Ct
Pressing the shutter button within 5 seconds causes the camera to start taking pictures for as long as the shutter button is pressed down (and the camera is not full). If the shutter button is not pressed within 5 seconds the camera reverts to normal picture taking mode.
Note: 1 In continuous mode, the camera allows pictures to be taken regardless of the available light, which could result in insufficient exposure. 2 In continuous mode, only every alternate field is grabbed hence capture rate is halved. For example, 12.5fps CIF and 7.5fps VGA 3 Continuous mode is suppressed when the FlashGun enable signal (GPIO2) is high.
3.2.7
Self timer - St
Pressing the shutter button starts a 10-second self-timer. The camera issues a short beep every second, followed by a longer beep. A further beep will then indicate that the picture has been taken (high beep - picture successful, low beep - insufficient light, picture not taken). The self-timer mode cannot be selected when the camera is full. The self-timer count down cannot be stopped once it has started.
3.2.8
Clearing the camera memory - CL
Pressing the shutter button once causes the camera to beep and the `CL' to start flashing. Pressing the shutter button again within 5 seconds clears all the images/audio clips in the camera and resets the counter.
3.2.9
Changing picture resolution - Hr/Lr
The resolution option is displayed, either Hr to change to high-resolution mode (if currently in lowresolution mode) or Lr to change to low-resolution (if currently in high-resolution mode). Press the shutter button within 5 seconds to select the resolution option, the camera beeps and the display is reset, indicating the number of pictures available in the new mode. The picture resolution can be changed at any time, that is the camera can store both high and low resolution images.
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STV0681 Hardware Interfaces
STV0681
4
4.1
STV0681 Hardware Interfaces
Sensor interface
STV0681 uses a standard ST digital interface from the sensor, and the sensor clock input is provided by an output from STV0681. The design of a camera using this chipset should be implemented as closely as possible to the reference design (Chapter 7), in which case the chipset can be regarded as a functional `black box', and no further details regarding the STV0681-sensor interface are required.
4.2
Memory interface
STV0681 is designed to interface to an external 16Mbit or 64Mbit SDRAM (see Table 1). The SDRAM device must have a 16 bit wide data bus and operate from a 3.3V supply. Two sizes of SDRAM memory are supported by STV0681, 16MBits (1M x 16 bits wide) or 64MBits (4M x 16 bits wide), the memory size is auto-detected by STV0681. STV0681 clocks the SDRAM at 6MHz, typically this is well below the figures offered by most manufacturers' devices.
4.2.1
SDRAM current consumption
For maximum system battery life while no pictures are being taken, and to meet requirements for USB compliance, an SDRAM should be chosen with the lowest possible self refresh current specification. In addition, the USB suspend mode current specification requires that the camera consumes less than 300A when un-tethered. Meeting this specification, which is included in the requirements for USB compliance, assumes an SDRAM with up to approximately 250A self-refresh current, based on a current consumption of approximately 50A for STV0681 + support circuit.
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STV0681 4.2.2 SDRAM interface timing requirements
STV0681 Hardware Interfaces
Figure 4: SDRAM Read Timing (16Mbit device, burst read)
tCK DCLK
tL
tH
CKE tCMS Command tCMH READ NOP PRECHARGE NOP
ACTIVE
A0-9,BA
ROW
COLUMN
A10
ROW tAS tAH tCMS tAC tOH tCMH
DQM
DQ tRCD READ Latency
DOUT M
DOUT M + 1
DOUT M + 2
DOUT M + 3
tRC tRAS tRP
DQ sample
DQ sample
DQ sample
DQ sample
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STV0681 Hardware Interfaces
Figure 5: SDRAM Write Timing (16Mbit device, burst write)
tCK DCLK
STV0681
tL
tH
CKE tCMS Command tCMH WRITE NOP PRECHARGE NOP
ACTIVE
A0-9,BA
ROW
COLUMN
A10
ROW tAS tAH tCMS tDS tDH tCMH
DQM
DQ tRCD
DIN M
DIN M + 1
DIN M + 2
DIN M + 3
tRC tRAS tRP
Table 3: Timing parameters for SDRAM read/write Symbol
tCK tCH tCL tAC tOH tCMS tCMH tAS 0 82.88 82.85 82.88
Min.
166.45 1/2 1/2
Max
166.89
Units
ns tCK tCK
Symbol
tDS tDH tRCD tRAS tRC tRP tRCD tAH
Min.
81.01 83.41 1 5 7 2 1 82.76
Max
Units
ns ns tCK
1/2
tCK ns ns ns ns
5
tCK tCK tCK tCK ns
4.2.3
SDRAM refresh period
The SDRAM refresh period from STV0681 is guaranteed to be inferior or equal to 15.6s during `Snapshot'/self-timer/continuous/tethered video modes of operation (that is not standby mode). In standby mode, the SDRAM is set to self-refresh, therefore no refresh from STV0681 takes place.
4.2.4
SDRAM initialisation period
The SDRAM initialisation period is currently set to 981s in STV0681.
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STV0681 Hardware Interfaces
4.3
USB interface
STV0681 includes a USB Version 1.1 compliant Universal Serial Bus Interface, including a transceiver. This allows direct connection from STV0681 to a USB connector with minimal additional hardware (that is a small number of passive discretes) - see Chapter 7 The USB interface interfaces the STV0681 to the USB at full speed 12MHz data rate. Some of the features are:
q q q q q q q q
Compliant with USB protocol revision 1.1. USB protocol handling. USB device state handling. Clock and data recovery from USB. Bit stripping and bit stuffing functions. CRC5 checking, CRC16 generation and checking. Serial to parallel conversion. Single bulk-end point. USB drivers are supplied by ST. For USB timing information, please refer to the USB specification V1.1.
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STV0681
4.4
UART module for RS232 interface
The UART module on STV0681 provides a 115200 baud full duplex serial interface to an external host.
4.4.1
RS232 physical interface
STV0681 does not support direct connection to a RS232 serial link. Physical line driver circuitry is required, e.g. using a standard RS232 transceiver chip, or by using a small number of low cost discretes (refer to Reference Design for details). Unscreened cable can be used, a suitable low cost connector is a 3.5mm stereo audio jack plug.
4.4.2
UART module overview
Receiving data The UART module in STV0681 receives serial data through the RXD pin. Data reception is initiated by a 1-to-0 transition on RXD, and the received data is sampled every 8.66s. If the RXD input is not 0 when the incoming data is first sampled, the UART module goes back to look for another 1-to-0 transition. This is to provide rejection of false start bits. If the start bit proves valid, reception of the rest of the frame proceeds.
Transmitting data
When a transmission is activated by STV0681, the contents of an internal transmit shift register are shifted onto the TXD pin, every 8.66s. The UART operates at 12MHz, which is not an integer multiple of 115200, so the actual baud rate is 115232 +/- 0.3%, which is well within the requirements of a typical 16x oversampling UART, which can tolerate a 3.75% error in baud rate.
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STV0681 Hardware Interfaces
4.5
Power management and battery type
STV0681 and the SDRAM require a 3.3V supply. When a VV6411 or VV6501 (3.3V) sensor is used, a single voltage regulator can regulate the supply for all three components from the battery, or the sensor on-board VReg can be used. These are explained more fully in the reference design.
4.5.1
Power switching to USB
Included in the USB compliance requirements, is the ability of the camera to report to the PC when connected to the USB bus, whether or not there is a fresh battery in the camera. This means that power sourcing from USB is required, which also saves on battery life while the camera is used in USB tethered video mode. In order to allow switching from battery to USB power, some additional hardware is required.
q q q
The USBDETECT input to STV0681 is used to detect that a USB power supply is connected If the USB is detected, additional hardware is used to switch off the battery An inrush protection circuit can protect the USB bus from current draw in the case of a low battery/ battery not fitted. This may be necessary to comply with the USB specification. For precise USB compliance requirements, please consult the USB specification version 1.1.
4.5.2
Switched sensor supply
Dependant on the hardware implementation, the SENSPWR output from STV0681 is used to put the sensor into suspend mode. This has a significant improvement on battery life.
4.5.3
Battery type
It is possible to use various battery types and configurations. The evaluation kit uses four 1.5V AAA cells.
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STV0681 Hardware Interfaces
STV0681
4.6
Quartz crystal
Regardless of the sensor type or anti-flicker requirements, the sensor + STV0681 chipset operates from a single 12MHz fundamental quartz crystal. For specification requirements, see Table 13. STV0681 includes an on-chip low jitter PLL. For PLL characteristics, see Table 12.
4.7
Numeric LCD interface
STV0681 supports a 2-digit LCD panel only, for alpha-numeric display.
4.7.1
LCD types
STV0681 connects to a non multiplexed, direct drive LCD with 2 x 7 segments. Many LCD types are compatible with this interface. The LCD refresh frequency is 34.7Hz.
4.7.2
LCD interface pinout
The convention for segment numbering is as follows: '0' connects to segment 'a', '1' connects to segment 'b', and so on, where a to g are standard for all 7-segment displays, as well as an LCD common output, giving fifteen signals in total.
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STV0681
STV0681 Hardware Interfaces
4.8
Switches and LED's
The GPIO lines on STV0681 have the following pre-defined functions, see Section 2.2 for user interface functionality. MODE push button and SHUTTER push button: GPIO0 and GPIO1: both push button inputs have internal de-bounce circuits, reducing the amount of hardware required externally. It is recommended that labelling is used on the camera casing to help the user understand the functioning of the 2-button interface.
4.8.1
Input to select between 50 and 60Hz flicker frequency: GPIO3
This allows for factory setting of the anti-flicker frequency, dependant on the final country of destination. See also Section 2.6. The polarity of this selection is detailed in the reference design.
4.8.2
LED indicator output: GPIO5
The LED output has an 8mA current sinking capability.
4.8.3
Other pins: GPIO2, 4, 6, 7
With STV0681, these pins are used, as detailed in Table 4.
Table 4: Other GPIO usage with STV0681 GPIO
Audio Record Audio Playback Flashgun
2
No No Yes
4
Yes No No
6
No Yes No
7
No No Yes
Their specific functions are detailed in the reference design and in the following documents available from ST:
q q
Audio: application note AN1310 Flashgun: application note AN1312
4.8.4
Audio Record Hardware interface
STV0681 implements the A/D conversion by outputting successive analogue levels (successive approximation) through the DAC output, which are compared with the actual signal level (output from the sensor microphone preamplifier), and the resulting high or low signal from the comparator is read at GPIO4. The sampling frequency is 11kHz, and the successive approximation is done at 8 bits resolution per sample. It is not possible to speed up the sampling frequency due to the limitation of STV0681 processing speed. An actual hardware implementation is given in the audio application note AN1310.
4.8.5
Audio Playback Hardware interface
STV0681 outputs the desired signal level through the DAC output, which is amplified to the speaker or headphone socket. GPIO6 is used to switch off the amplifier during periods of audio recording, to prevent the successive approximation waveform from being heard during periods of recording, and to reduce the power consumption and unwanted crackle through the speaker. An actual hardware implementation is given in the audio application note AN1310.
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STV0681
4.9
Flashgun hardware interface
STV0681 will revert to flashgun exposure when it detects GPIO2 is high. Ideally the hardware should combine the two factors of (a) user intention (e.g. user switches on flashgun) and (b) charge sensing (i.e. flash is charged up and ready to fire). These two factors (a) and (b) are independent, since there may be a delay of several seconds between switching on the flashgun charger, and the flashgun being able to fire. To revert to flashgun exposure before the flashgun is completely charged up would cause very bad pictures to be taken in low light conditions because there is no "low light" threshold when flashgun exposure is enabled, since the camera expects a flash to fire. A suggested flashgun hardware interface is given in the flashgun application note AN1312. When flashgun exposure is enabled and the shutter button is pressed, a picture is taken and the flash trigger pin GPIO7 is pulsed low at the correct point in time so that all lines of the CMOS imager are exposed.
4.10
IR filter
An Infra-Red Blocking Filter is required to achieve correct colour response. The exact specification for the IR filter characteristics are given in the reference design manual.
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Customising the STV0681
5
Customising the STV0681
The firmware inside the STV0681 is stored in ROM and may not be changed. It is possible, however, to use an external serial EEPROM to store certain information to allow a degree of customization of the device. The STV0681 reports a USB Vendor ID (VID) of 0553(hex) and a Product ID (PID) of 0202 (hex). Alternative values for the VID and PID as well as Manufacturer and Product strings may be stored in an external EEPROM. In addition to USB descriptor information, the EEPROM may also be used to set various other parameters as follows:
q q
Auto power-down time: this is the length of time before the STV0681 shuts down after no activity. Mode button power-down time: the length of time you must hold the Mode button to powerdown the system. 50Hz/60Hz flicker-free selection: the EEPROM allows this selection to be via a GPIO pin on the STV0681 or fixed at either 50Hz or 60Hz Number of self-timer beeps
q
q
5.1
External EEPROM
An external 128byte serial EEPROM may be used in conjunction with STV0681 to hold customer specific information. The EEPROM is connected onto the sensor IIC bus and must be set to IIC address A0 (hex). The EEPROM is auto-detected by the STV0681 and no additional changes need to be made. A suitable EEPROM device is manufactured by STMicroelectronics part number M24C01W (alternatives are available from other suppliers).
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Customising the STV0681
STV0681
5.2
EEPROM data format
Location(decimal)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 20 21-54 (max) 55 56-89 (max) 90 91-127 (max)
Contents
Leave blank VidLo, The low byte of the Vendor ID VidHi, The high byte of the Vendor ID PidLo, The low byte of the Product ID PidHi, The high byte of the Product ID Max Power (in units of 0.5mA) Max Power with audio playback enabled (in units of 0.5mA) Auto powerdown time Hi byte (in units of 256ms) Auto powerdown time Lo byte (in units of 10ms) Mode button press time Hi byte (in units of 256ms) Mode button presss time Lo byte (in units of 10ms) 50Hz/60Hz flicker free selection 0 = board link (GPIO3) , 1 = 50Hz, 2 = 60Hz Number of self-timer beeps CheckSum - low byte of sum of EEPROM locations 1 to 12 inclusive. Length of Manufacturer String Manufacturer String (ASCII codes) Length of Product String Product String (ASCII codes) Length of Interface0 String Interface 0 String (ASCII codes)
5.3
Programming the EEPROM
There is no facility to program the EEPROM using the STV0681 itself and so the device must be programmed before fitting it to the PCB.
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STV0681
Software support
6
6.1
Software support
General features
The chipset is a dual-mode camera, i.e. stills and video, and is supported by a range of demonstration software, standard drivers, and software development options.
PC
Driver software is available to support both USB and RS232 interfaces. Drivers are available for TWAIN, WIA, Video for Windows (VfW) and DirectShow (DS) depending on the Operating System as listed below:
q q q
Win98/Win98SE/WinME - VfW and TWAIN Win2k - DS, VfW and TWAIN WinXP - DS, VfW, WIA and TWAIN
Mac
Quicktime drivers and a Photoshop stills plug in for MacOS 8.6/9.0/9.1/9.2 are supported. The driver will also run under MacOS X in Classic Mode. Example software applications (PC only) are provided to create. AVI video files from untethered continuous capture of images (AVICreator), to upload still images and recorded sounds (LCDCdemo) and to download.WAV files from the PC to the camera (CustomSound). In each case, PC source code is provided to assist in OEM software development using the SDK. ST colour processing and defect detection/correction software runs on the host and is supplied under licence agreement as part of all host software/drivers/SDK
6.1.1
Still image upload
This is available through demonstration software, OEM custom software, or using standard TWAIN applications. Features include:
q q q q q
Fast upload through USB, or upload through RS232. Colour display of image thumbnails for picture selection. Download of full image once selected by user software. Automatic detection and correction of sensor defects Colour processing of full image, using the ST colour process The above features also apply to "AVI Creator" or any OEM custom software for AVI video creation at part of pictures taken while un-tethered, since this is essentially a "stills" function.
6.1.2
Streaming video (only while tethered to USB)
This is available through demonstration software, or using standard VfW applications. Features include:
q q q
Streaming video through standard VfW driver Automatic detection and correction of sensor defects Colour processing of full image, using the ST colour process
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Software support
STV0681
6.2
Software installation
The following software support is only available to OEMs. Access to the latest installation files is possible through a password-protected web page, contact ST for details. The installation files are for the following:
q q q
Drivers (always check the Web site for latest driver version). EVK software, i.e. LCDCdemo.exe and AVIcreator.exe, G2Video.exe, and CTItest2.exe SDK installation: source code for sample applications, and documentation
6.2.1
Driver support available
Table 5: Driver choices Interface type:
RS232 USB
Microsoft WindowsTM: PC Operating system
Win9x, WinNT4, Win2k, Windows Millennium Windows XP N/A
Microsoft WindowsTM:
Win98 and Win2k only, Windows millenium Windows XP 8.6, 9.0, 9.1, 9.2
Mac OS
6.2.2
Note:
EVK software
The following is also supplied with evaluation kits/demonstration units, but all the following software is only for demonstration purposes and should NOT be supplied as an end-user product. However, application-level source code (i.e. not driver/colour processing source) for LCDCdemo.exe, AVI creator, and CTItest.exe is available as part of the SDK, which allows similar applications to be built by the software developer:
1 2 3 4 Simple demonstration software LCDCdemo.exe for uploading thumbnails and images. AVIcreator.exe software for uploading continuous images for creating `movie' clips. G2Video.exe is a VfW application which shows streaming video while tethered to USB and allows creation of.AVI video clips. CTItest.exe is only for debugging purposes, for software developers using the SDK
6.2.3
Software Development Kit (SDK) and source code
A software development kit allows the OEM to develop a custom application which calls the same range of drivers as listed in Section 6.2.1, hence allowing the OEM application to perform picture download, thumbnail display, and colour processing using the ST colour process. Inclusion of source code for the applications listed in Section 6.2.2 allows the software developer to use these as the basis for their own application. The SDK is supplied by ST as a 32-bit DLL format, running on Microsoft Windows 98/Win2KTM, and accessed through a documented software interface. Development requires Microsoft Visual Studio Version 6 or later. This provides the basis for developing a custom software application for stills.
Note:
Source code for PC Drivers, Defect Correction and Colour Processing algorithms are not available.
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Detailed Chipset Specifications
7
7.1
Detailed Chipset Specifications
Typical camera specifications
The following data assumes that the camera has been built according to the ST Reference Design. Dual USB or battery power supply is only possible when the required power switching hardware is included. Figures are approximate and depend on actual components sources.
Table 6: Typical camera specifications Supply voltage Operating temperature range Max. RS232 cable length supported CIF output QCIF output VGA output QVGA output SDRAM storage and image upload format PC driver output format
4.1-6V (when powered from battery or USB) 0oC - 40oC 2m 352 x 288 pixels 176 x 144 pixels 640 x 480 pixels 320 x 240 pixels Raw Bayer Colour RGB bitmap
Table 7: Approximate shutter speeds Sensor resolution
CIF VGA
Min.
8 s 8 s
Max
44 ms 66 ms
7.2
Absolute maximum ratings
Table 8: STV0681 absolute maximum ratings Parameter
Ambient temperature Storage temperature Voltage on USB D+/D-
Range
0 to 40 -50 to 150 0-VDD
Units
C C V
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7.3
STV0681 specifications
Table 9: STV0681 specifications Parameter
Supply voltage Current consumption (normal operation) Stand-by current consumption Package Exposure control -
Min.
3.0
Typ.
3.3 18 10
Max.
3.6 -
Units
V mA A
100TQFP (14x14x1.4) 1 000 000: 1
7.4
USB specifications
Table 10: STV0681 USB specifications Parameter
VDD VILU VIHU VIHUZ VDI VCM VOLU VOHU VCRS RPU RPD TFR TFF TFRFM ZDRV Power Supply USB differential pad D+/D- input low USB differential pad D+/D- input high (driven) USB differential pad D+/D- input high (floating) USB differential pad D+/D- input sensitivity USB differential pad D+/D- common mode voltage USB differential pad D+/D- output low voltage USB differential pad D+/D- output high voltage USB differential pad D+/D- output signal cross over voltage USB differential pad D+/D- pull up resistor USB differential pad D+/D- pull-down resistor Rise Time Fall Time Differential Rise Time and Fall Time Matching Driver Output Resistance 2.0 2.7 0.2 0.8 0.0 2.8 1.51 1.425 14.25 4 4 96 24.7 26.6 2.5 0.3 3.6 1.79 1.575 15.75 20 20 98 30.0 3.6
Description
Min.
3.0
Typ.
3.3
Max.
3.6 0.8
Units
V V V V V V V V V k k ns ns %
Notes
1 2
Note 3 Note 4
Note: 1 VDI = |(D+) - (D-)| 2 VCM includes VDI range. 3 TFRFM =(TFR / TFF). 4 ZDRV includes an external resistor of 20 Ohms serial to this transceiver.
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Detailed Chipset Specifications
7.5
DC characteristics
Table 11: STV0681 DC characteristics Parameter Description
CMOS input low voltage CMOS input high voltage CMOS schmitt input low to high threshold voltage CMOS schmitt input high to low threshold voltage Threshold point Output high voltage Output low voltage 2.4 0.4 0.65 VDD 2.15 1.05 1.65
Min.
Typ.
Max.
0.35 VDD
Units
V V V V V V V
VII VIH VT+ VTVT VOH VOL
7.6
PLL characteristics
Table 12: STV0681 PLL characteristics Parameter Conditions
@VCOfreq = 240MHz - 312MHz
Symbol
--VDD
Min.
-45 3 0.7VDD ---
Typ.
-50 3.3
Max.
500 55 3.6 0.8 VDD
Unit
ps % V V V ms ns
Peak to peak jitters Duty cycle Operating voltage range Input low voltage Input high voltage Pull in Time + Locking Time Output Slew Rate
VDD=3.3V VDD=3.3V
VIL VIH Ready
-0.100+0.1082*CL
0.1 --
CL: Output Load (pF)
Tsr(Fout)
7.7
Crystal tolerance
Table 13: STV0681 crystal tolerance Parameter
Crystal specification Crystal frequency Frequency tolerance Temperature stability Operating temperature -10
Min.
Typ.
Max.
Units
50/50/10/30 (12mhz Fundamental) 12.000 50 50 MHz ppm ppm C
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STV0681
7.8
Typical current consumption of complete camera
The following data assumes that the camera has been built according to reference design referred to in Chapter 10. Figures are approximate and depend on actual components sources - see notes. The sensor operates at @ 3.3V DC
Table 14: Current consumption, complete STV0681+VV6411/6501 camera Mode
'Snapshot'/Continuous/ Self timer mode (while un-tethered) 'Snapshot'/Continuous/ Self timer mode (while tethered to PC) While playing back audio sounds through speaker Standby mode (when NOT connected to USB)
Typical
60mA
Comments
Assuming appropriate hardware included, power is sourced from PC while USB connected.
60mA
90mA
Assuming 8 speaker as explained in application note AN1310 Total current in this mode equals: STV0681 standby current consumption (see Note 1) + SDRAM self-refresh current (see Note 2) + peripheral circuitry (approx. 50A). + Sensor suspend mode current
Approx. 270A + SDRAM self-refresh current (see Note 2) + sensor suspend mode current
PC Suspend mode
Approx. 300A + SDRAM (when connected to USB): self-refresh current (see Note 2) + sensor Sensor SUSPEND pin suspend mode current asserted
Total current in this mode equals: STV0681 Standby current consumption (see Note 1) +SDRAM self-refresh current (see Note 2) + peripheral circuitry (approx. 50A) + 200A, based on 1.5k pull-up in camera and 15k pulldown in PC. + Sensor suspend mode current Total current in this mode equals: STV0681 Standby current consumption (see Note 1) +SDRAM self-refresh current (see Note 2) + peripheral circuitry (approx. 50A). Total current in this mode equals: STV0681 Standby current consumption (see Note 1) +SDRAM self-refresh current (see Note 2) + peripheral circuitry (approx. 50A).
Standby mode (when not connected to USB): sensor powered off using FET (see Note 3) PC Suspend mode
Approx. 270A + SDRAM self-refresh current (see Note 2)
Approx. 100A + SDRAM (when connected to USB): self-refresh current sensor powered off using (see Note 2) FET (see Note 3)
Note: 1 See Table 9 from Section 7.3 2 From limited evaluation, typical self-refresh current figures of certain SDRAM chips are well below manufacturers' maximum specification, e.g. 100-250A. 3 Option included in reference design to save current consumption, which can increase battery life and increase chances of meeting USB suspend mode compliance requirements.
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STV0681 pin description
8
8.1
STV0681 pin description
STV0681 pinout
Figure 6: STV0681 pinout diagram
COMP_OUT
SENS_CLK
FLASH_EN
PLL_GVSS 53
SENSPWR
66
65
64
63
62
61
60
59
58
54
52
75
74
73
72
71
70
AUD_VSS
LO_BAT_REF
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
51
69
68
67
57
56
55
PLL_AVDD
PLL_AVSS
SENSRST
SHUTTER
FL_TRIG
AMP_EN
MODE
QCLK
SD[0]
SD[1]
SD[2]
50/60
SD[3]
VDD
RXD
SDA
TXD
VSS
LED
SCL
50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26
RESET XOUT XIN TEST2 TEST1 TEST0 USBUSB+ USB_DET AD_4 AD_3 VDD VSS AD_5 AD_2 AD_6 AD_1 AD_7 AD_0 AD_8 AD_10 AD_9 AD_13 AD_11 AD_12
LO_BAT DACRES DACOUT AUD_VDD PIEZO LCD_COM VSS VDD LCD2_6 LCD2_5 LCD2_4 LCD2_3 LCD2_2 LCD2_1 LCD2_0 LCD1_6 LCD1_5 LCD1_4 LCD1_3 LCD1_2 LCD1_1 LCD1_0 DQ_0
STV0681
TQFP100
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
VDD
VSS DQ_10 DQ_6
DQ_15 DQ_1 DQ_14 DQ_2 DQ_13
DQ_3 DQ_12
DQ_4 DQ_11
DQMU
DQ_9
DQ_7 DQ_8 DQML
DQ_5
WE
CAS
DCLK RAS
CKE
ADCS 7283313C
CS
25
100 1 2 3 4 5 6 7 8 9
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STV0681 pin description
STV0681
8.2
STV0681 pin description
Table 15: STV0681 pin listing Pin no. Signal Type Description drive
Sensor Interface
65 64 56 57 58 59 60 61 62 63 SENSPWR SENSRST SCL SDA SD[3] SD[2] SD[1] SD[0] QCLK SENS_CLK Output, active high Output, active low Input/Output (OD,T) Input/Output (OD,T) Input (S,T) Input (S,T) Input (S,T) Input (S,T) Input (S,T) Output Power-up Sensor Reset Sensor Sensor serial interface Sensor serial interface Sensor data Sensor data Sensor data Sensor data Qualification clock from sensor Clock output to sensor 4mA 2mA (SL) 2mA (SL) 4mA (SL) 4mA (SL)
I/O and Camera Control pins
75 74 73 72 71 68 67 66 MODE SHUTTER FLASH_EN 50/60_SEL COMP_OUT LED AMP_ENABLE FL_TRIG Debounced input Debounced input Input Input Input Output (OD) Output, active low (OD) Output, active low (OD) Push button (Wake-up/Mode) Push button (Shutter/Confirm) Enable Flash Exposure (Active High) S elect between 50Hz and 60Hz lighting Output from Audio Comparator LED indicator Audio Amplifier Enable Flashgun trigger 8mA (SL) 8mA (SL) 8mA (SL)
USB Interface
42 USBDET Input (S) Detect Power source from USB. (For camera with RS232 only, this pin should be tied to GND) 43 DATA+ Input/Output USB bus (For camera with RS232 only, this pin should be connected to test points to allow for USB production test (lens focussing)) 44 DATAInput/Output USB bus. (For camera with RS232 only, this pin should be connected to test points to allow for USB production test (lens focussing)) USB specific ation V1.1 complia nt I/O
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ADCS 7283313C
STV0681
Table 15: STV0681 pin listing Pin no. Signal Type
STV0681 pin description
Description
drive
RS232 Interface
54 TXD Output Serial data transmit (For camera with USB only, this pin should be tied to RXD) 55 RXD Input (S) Serial data receive (For camera with USB only, this pin should be tied to TXD) 4mA (SL)
STV0680B Master Clocks and Reset
48 49 50 XIN XOUT RESET Input Output Input (S) Quartz Crystal IN Quartz Crystal OUT Active (LOW) STV0680B reset
System Memory (SDRAM) Interface
20 22 24 32 34 36 40 41 37 35 33 31 29 30 27 26 DQMU DCLK CKE AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 AD8 AD9 AD10 AD11 AD12 Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Data input/output mask for dram_DQ[15:8] Clock: all SDRAM input signals are sampled on the positive edge Clock enable: activates (HIGH) and deactivates (LOW) the SDRAM CLK signal SDRAM address A0 SDRAM address A1 SDRAM address A2 SDRAM address A3 SDRAM address A4 SDRAM address A5 SDRAM address A6 SDRAM address A7 SDRAM address A8 SDRAM address A9 SDRAM address A10 SDRAM address A11 for 64M SDRAM or BA for 16M SDRAM SDRAM address A12, BA0 for 64M SDRAM, unused on 16M 2mA (SL) 4mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL)
ADCS 7283313C
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STV0681 pin description
Table 15: STV0681 pin listing Pin no.
28 25 23 21 19 18 100 2 4 6 8 10 14 16 17 15 13 9 7 5 3 1
STV0681
Signal
AD13 CS RAS CAS WE DQML DQ0 DQ1 DQ2 DQ3 DQ4 DQ5 DQ6 DQ7 DQ8 DQ9 DQ10 DQ11 DQ12 DQ13 DQ14 DQ15
Type
Output Output, active low Output, active low Output, active low Output, active low Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output Input/Output
Description
SDRAM address A13, BA1 for 64M SDRAM, unused on 16M Chip select: enables (registered LOW) and disables (registered HIGH) the SDRAM command decoder. SDRAM row address strobe command SDRAM column address strobe command SDRAM write enable command Data input/output mask for dram_DQ[7:0] SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data bus SDRAM Data bus SDRAM Data bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus SDRAM Data Bus
drive
2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL)
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ADCS 7283313C
STV0681
Table 15: STV0681 pin listing Pin no. LCD Interface
83 93 94 95 96 97 98 99 86 87 88 89 90 91 92 LCDCOM LCD1_6 LCD1_5 LCD1_4 LCD1_3 LCD1_2 LCD1_1 LCD1_0 LCD2_6 LCD2_5 LCD2_4 LCD2_3 LCD2_2 LCD2_1 LCD2_0 Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output LCD Common LCD digit 1 segment G LCD digit 1 segment F LCD digit 1 segment E LCD digit 1 segment D LCD digit 1 segment C LCD digit 1 segment B LCD digit 1 segment A LCD digit 2 segment G LCD digit 2 segment F LCD digit 2segment E LCD digit 2segment D LCD digit 2segment C LCD digit 2 segment B LCD digit 2 segment A
STV0681 pin description
Signal
Type
Description
drive
4mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL) 2mA (SL)
Piezo Interface
82 PIEZO Output Direct connection to piezo buzzer 8mA (SL)
Battery Level Comparator Interface
78 LO_BAT Input (A) Battery level comparator input. The voltage on low_bat is compared to the reference to determine the battery status 1.22V battery level comparator reference input
77
LO_BAT_REF
Input (A)
ADCS 7283313C
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STV0681 pin description
Table 15: STV0681 pin listing Pin no. Signal Type Description
STV0681
drive
Power and Ground
12, 38, 70, 84 11, 39, 69, 85 76 81 53 51 52 DVSS DVDD AUD_VSS AUD_VDD PLLGVSS PLLAVDD PLLAVSS Power pin Power pin Power pin Power pin Power pin Power pin Power pin Digital Ground Digital Power Audio DAC Ground. Requires clean supply. Audio DAC Power. Requires clean supply. PLL Guard Ground PLL Analog Power PLL Analog Ground
Non-user pins
45 46 47 79 80 TEST0 TEST1 TEST2 DACRES DACOUT Input Input Input I(A) O (A) Non-user pin - connect to 3V3 Non-user pin - connect to 3V3 Non-user pin - connect to 3V3 DAC bias amplifier reference input. 8-bit DAC current source output. 0-10mA
Key
SL OD S A T slew rate limited output open drain output Schmidt input analogue input/output 5V tolerant pad (these pads do not have diode protection)
Note: 1 Where the I/O pad type is not explicitly defined, assume CMOS.
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ADCS 7283313C
STV0681
STV0681 package mechanical data
9
STV0681 package mechanical data
mm Dim. Min.
A A1 A2 B C D D1 D3 e E E1 E3 L L1 K 0.45 0.05 1.35 0.17 0.09 16.00 14.00 12.00 0.50 16.00 14.00 12.00 0.60 1.00 3.5 (min.), 7 (max.)
D D1 D3 A1 75 76 51 50
0.076mm .003 inch Seating Plane
inch Max.
1.60 0.15 0.002 0.053 0.007 0.003 0.630 0.551 0.472 0.019 0.630 0.551 0.472 0.75 0.018 0.024 0.039 3 0.030 0.055 0.009
Typ.
Min.
Typ.
Max.
0.063 0.006 0.057 0.011 0.008
1.40 0.22
1.45 0.27 0.20
TQFP100
A A2
e E3 E1 E
B
Pin 1 identification
100
26
1
25
K TQFP100M
L
C
L1
ADCS 7283313C
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Evaluation Kit (EVK)
STV0681
10
Evaluation Kit (EVK)
STMicroelectronics can supply an Evaluation Kit for initial evaluation and design-in. The EVK includes an STV0681 Motherboard PCB and two lensed sensor daughter boards (CIF and VGA). Additional motherboards and daughter boards may be ordered separately. The EVK PCB includes SDRAM memory, connectors, numeric LCD display, battery holder, push buttons/switches, audio record and playback circuitry, flashgun interface circuitry, and a flashgun hotshoe connector (for use of a standard camera flashgun). Optional PCB links enable alternate functionality, and demonstration software is included, allowing for tethered video, upload to the PC of pictures, sounds, and AVI movie clips, and download to the camera of custom sounds. A reference design manual, giving the camera designer everything required for standard features and audio record/playback is available, including schematics, explanatory notes, parts list, and layout advice.
10.1
Ordering details
Table 16: Ordering details for STV0681 + VV6411/6501 Evaluation Kits Description
STV0681 companion processor VV6411 CIF color CMOS sensor (36LCC package) VV6501 VGA color CMOS sensor (36LCC package) Complete Evaluation Kit STV0681 complete Evaluation Kit (includes STV-681-M01, STV-6411C-D01 and STV6501C-D01) Additional EVK Components Evaluation Kit Motherboard Sensor Daughter Board with VV6411 Sensor Daughter Board with VV6501 STV-681-M01 STV-6411C-D01 STV-6501C-D01 STV-681-E01
Part number
STV0681 VV6411C036 VV6501C001
Note:
All Evaluation Kits include hardware and software support for Audio, Custom sounds, and Flashgun features.
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ADCS 7283313C
STV0681
Evaluation Kit (EVK)
10.2
Technical support
Technical support information, such as datasheets, software downloads,etc, for products of the STMicroelectronics Imaging Division can be found at www.st.com (click on Imaging products) General sales/technical enquiries can be directed to regional email contacts: asiapacific.imaging@st.com centraleurope.imaging@st.com france.imaging@st.com japan.imaging@st.com nordic.imaging@st.com southerneurope.imaging@st.com ukeire.imaging@st.com usa.imaging@st.com
ADCS 7283313C
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STV0681
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
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ADCS 7283313C
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