March 2003 ADCS 7283313C 1/44
STV0681
DUAL-MODE DIGITAL CAMERA CO-PROCESSOR
®
DESCRIPTION
STMicroelectronics Imag ing Divisi on has produced
the camera co-processor STV0681 which, used
with CIF/VGA sensors as part of a low cost dual-
mode camer a chipset, allo ws a ne w l ine 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:
●Support for VV6 411 (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 capt ure while unteth ered (except
when Flashgun enabl ed) and do wnl oading 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.
●Softwar e De velo pment Kit (SD K) allo ws OEM
PC Software applications to be written.
●Quick Po wer Do w n ( b y hol ding M ode Butto n).
●“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 uploade d 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 pla yed bac k on
the camera, with the addition of an amplifier chip
and speaker or headphone socket.
By auto-detecting hardware, STV0681 will only
enabl e these additional functi ons if audio har dw are
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 desig n guid eli ne s are a vailable fr om ST as
a reference design manual (see
Chapter 10
).
Note: Simultaneous audio record and
continuous video capture is not possible.
STV0681
2/44 ADCS 7283313C
Table of Contents
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.1 Digital camera chipset ..........................................................................................................5
1.2 Key system features .............................................................................................................6
Chapter 2 Detailed Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
2.1 Sensor type and image formats ...........................................................................................9
2.2 User interface .....................................................................................................................10
2.3 Battery level detect and USB auto-switch ..........................................................................12
2.4 Audio record and playback .................................................................................................12
2.5 PC interface options and software support ........................................................................13
2.6 Anti-flicker exposure and gain control ................................................................................14
Chapter 3 Camera Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.1 Modes available .................................................................................................................15
3.2 Description of modes .........................................................................................................16
Chapter 4 STV0681 Hardware Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
4.1 Sensor interface .................................................................................................................18
4.2 Memory interface ...............................................................................................................18
4.3 USB interface ..................................................... ................................. ........... ....................21
4.4 UART module for RS232 interface .....................................................................................22
4.5 Power management and battery type ................................................................................23
4.6 Quartz crystal .....................................................................................................................24
4.7 Numeric LCD interface .......................................................................................................24
4.8 Switches and LED’s ...........................................................................................................25
4.9 Flashgun hardware interface ..............................................................................................26
4.10 IR filter ............................... ........... ........... ........... ................................. ...............................26
Chapter 5 Customising the STV0681 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
5.1 External EEPROM .............................................................................................................27
5.2 EEPROM data format ........................................................................................................28
5.3 Programming the EEPROM ...............................................................................................28
ADCS 7283313C 3/44
STV0681
Chapter 6 Software support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
6.1 General features ................................................................................................................29
6.2 Software installation ...........................................................................................................30
Chapter 7 Detailed Chipset Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
7.1 Typical camera specifications ............................................................................................31
7.2 Absolute maximum ratings .................................................................................................31
7.3 STV0681 specifications ......................................................................................................32
7.4 USB specifications ....................... ........... ........... ................................. ...............................32
7.5 DC characteristics ..............................................................................................................33
7.6 PLL characteristics .............................................................................................................33
7.7 Crystal tolerance .......................... ........... ........... ........... ................................. ....................33
7.8 Typical current consumption of complete camera ..............................................................34
Chapter 8 STV0681 pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
8.1 STV0681 pinout .................................................................................................................35
8.2 STV0681 pin description ....................................................................................................36
Chapter 9 STV0681 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Chapter 10 Evaluation Kit (EVK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
10.1 Ordering details ..................................................................................................................42
10.2 Technical support ...............................................................................................................43
STV0681
4/44 ADCS 7283313C
Document Revision History
Revision Draft Date Comments
A 1.0 May 2001 Initial release (product preview)
B 4.0 April 2002 Document status updated to datasheet.
Major changes: removed references of VV6410 and VV6444
sensors
C4.1November
2002 Removed all salestypes for imaging sensors:
removed section 6.1
addit i on of chapter 5 - Cu stomizing the ST V0681
Replacement of section 6.1 - Gen eral features (in Chapter 6 -
Software sup po rt)
ADCS 7283313C 5/44
STV0681 Introduction
1 Introduction
1.1 Digital camera c hipset
1.1.1 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 outlinin g what peripheral compone nts are req uired/supported in order to compl ete a camera
using the chipset. Such a camera i s particularly suited to dual-mode di gital st ills or t o y appli cations .
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 i s pro vided, w hen tether ed throug h USB . It all ows f or Vi deo f or Micro soft Windo ws
applications, and ‘video clips’ to be recorded while untethered by continuously capturing images in
‘continuo us’ mode. Image s are then do wnloaded to th e PC for playbac k, using softw are 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 pla yba c k hardw are fitted to the camera , it is possib le to do wnload 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 allow s f or camer a “Theme Music” , custom sounds such as an imitation shu tter “Clic k-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.
Downl oading sounds is possi b le with the use of an OEM appl ication de v elop ed using the SD K, 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 qual ity. STV0681 flashgun suppo rt includes modified e xposure con trol, an enab le input and a
correctly timed trigg er output. Although i t remains the responsibility of the OEM to source a suitab le
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.
Introduction STV0681
6/44 ADCS 7283313C
1.1.6 “Delete Last” function
An additional user interface function is available in STV0681 with either audio record or play back
hardware fi tted. With these, the user can delete the last image or contin uous 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 camer as designed for STV0680B , and uses
the same PC/Mac drivers, however the change of dev ice pinout means that some PCB re-design
will be required.
Precise design guidel ines are av ailab le from ST as a refer ence design (see
Chapter 10
). A software
development kit (SDK) for PC is av a ilable from ST to interface to the camera and pr o vi de the basis
to develop a custom software application for stills and/or video. It includes colour processing
software.
1.2 Key system features
The key features of a typical camera based on the STV0681 chipset are listed here below.
1.2.1 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 memor y). See
Table 1
.
●Automatic anti-flicker exposure and gain control
●Support for flashgun.
Figure 1: Typical camera system block diagram
CMOS Sensor
Sensor data
STV0681
USB interface
16MBit or 64MBit
SDRAM
Lens +
RS232
I/F
USB
I/F
memory
I/F
RS232 interface
GPIO
Sensor
I/F
PWM
LED
4.5 - 6v Battery e.g.
12MHz XTAL
Audio DAC
LCD
Driver
2x7seg.LCD
Push
Transceiver
Piezo
“Mode”
Buzzer
“Shutter
4-5v (Nominal) supply from Battery or USB
3-4 x AA, AAA, etc.
Power
Management
Circuit (Discretes)
Detect Low
Battery
to PC
to PC
Circuit (Discretes)
Sensor clock
IR Filter
VV6501 (VGA)
VV6411 (CIF)
Image Array
Audio
Pre-Amp
Speaker
Microphone
Comparator
Buttons:
/Record”
OEM Flashgun
Enable/Trigger
Module
Audio
Enable/Trigger
Flashgun
Amplifier
VReg
3v3 supply
Subject
ADCS 7283313C 7/44
STV0681 Introduction
1.2.2 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.
1.2.3 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:
●TWAIN driver to suit all TWAIN compatible imaging applications
●Video for Microsoft Windows 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 softw are can be d e v el oped b y using the SDK (for SDK av ai lability, 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.
1.2.4 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.
Introduction STV0681
8/44 ADCS 7283313C
●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 compli ance requirements are listed in the USB specifi cation. Ho we v er , in a camera designed
using this chipset, the following must at least be included: (a) an SDRAM with sufficiently low self-
refresh current, (b) USB inrush protection circuitry to maintain sufficient supply voltage to the 5V
sensor. See
Section 7
for further details.
1.2.5 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.
ADCS 7283313C 9/44
STV0681 Detailed Features
2 Detailed Features
2.1 Sensor type and image f ormats
The sensor type is auto-detected b y STV0681, the cor rect sensor timing is enab led and the corr ect
image resolutions are enabled, as shown in
Table 1
.
F or stills photogr aph y, ‘High’ or ‘Low’ resolution mode can be selected, to giv e CIF or QCIF pictures
from a CI F sensor, and VGA or QVGA from a VGA sensor (see
Table 1
). Reduced resolution allo ws
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 Windows driver)
can activ ate tether ed video mod e, re gardle ss of the user inputs to the camer a b uttons . In this case ,
the image resolution is controlled by the PC driver.
Note: 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
(“Camer a control”, as part of the SDK f or PC , and “Plug ’n Sav e” f or Mac) which can monitor wheth er
a camera is connected and warns the user if activa ting the VfW driver causes SDRAM contents to
be deleted.
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 l ength of audio clip , b ut a rough guide i s that if 1 CIF image uses the same
amount of SDR AM as 10sec of au dio , and o ne V GA imag e uses the same amount of SDRAM as 30
sec. of audio.
3 A CIF camer a wi th STV068 1 and 64 Mbit SDRAM can stor e up to 320 im ages b y usin g 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.
Table 1: Image modes supported
Sensor
Image Size Resolution
mode Final Image Size
Max. no . o f
images
stored in
16MBit
memory
(
Note 2
)
Max. no. of
images
stored in
64MBit
memory
(
Note 2
)
Approximate
VfW framerate
(
Note 1
)
CIF 352 x 288 Hig h CIF 352 x 288 20 80 15 frames/sec.
Low QCIF 17 6 x 144
(Subsampled) 80 322
(see
Note 3
)22.5 frames/sec.
VGA 640 x 480 Hig h VGA 640 x 480 (6) 26 2 frames/sec.
Low QVGA 32 0 x 240
(Subsampled) (26) 107
(see
Note 3
)12 frames/sec.
Detailed Features STV0681
10/44 ADCS 7283313C
2.1.1 IR filter
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 interf ace supported by S TV0681 comprises of user controls , buzz er sounds or cu sto mized
sounds and visual displays.
2.2.1 Push buttons
The f ollo wing are the fun ctions which are supported by the chipset. These functions ar e achie vable
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
.
2 Shutter button (shutter/confirm action)
This button allows the user to take a picture or confirm an action, as shown in
Chapter 3
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 suppor ts a 2x7 segment LCD panel. In ‘Snapshot’ mode and continuous capture mode,
this LCD p anel displa ys the num ber of pict ures still a v ailab le . This is useful to identi fy when the use r
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.
Note: A CIF camer a wi th STV0681 an d 64 Mbit SDRAM can stor e up to 320 im ages b y usin g QCIF mode .
When more than 99 images are still av ailab le, the LCD display remains at 99. When the n umber 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
.
ADCS 7283313C 11/44
STV0681 Detailed Features
2.2.4 Piezo buzzer
An on-chip pulse width modulator (PWM) generates buzzer sounds to signal certain events. The
distinctiv e sounds are characteristic of the type of e vents indicat ed by the b uzzer , as described here
below.
1 Camera has been ‘Woken up’ from standby mode (either by the user pressing a button, by re-
connecting the power source, or by connecting a USB/RS232 connection).
2 Camer a has ‘gone to sleep ’ that is mov e d into standby mode. Pictures are retai ned i n memory.
3 Picture was taken successfully once the user had pressed the capture button.
4 Picture has NOT been taken when the user pressed the capture button because of insufficient
light, or because the exposure con t rol was not ready fol lowing a r api d change of lighting in the
scene.
5 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.
6 End of continuous capture in un-tethered ‘Continuous’ mode due to full memor y.
7 Self-timer activated, count down has started.
2.2.5 Custom sounds
A camera which includes ST V0681 and audio pl a ybac k har dw are can ha v e 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 pi cture
Bad picture
(Normally due to insuf f i cient ligh t)
Memor y full
Self timer #1
Self timer #2
Low resolution
High r esolution
Picture delete
Soun d de l ete
Continuous clip delete
Clear memory
Confirm action
Low power
Flashgun ON
Flashgun OFF
Flashgun Trigger
Detailed Features STV0681
12/44 ADCS 7283313C
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 demonstra tion PC ap pl ication “CustomS ounds” i s available from ST, however thi s i s no t i ntend ed
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 batter y 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 LC D displa y flashes , indicating that the battery is lo w . When
a USB connection has been detected, the LCD display does not flash.
Note: It may be a requirement of certain USB compliance tests that such additional hardware is included
in the camer a desig n, in or der to e nab le the cam era to s wit ch to supply fr om USB a nd hence re port
back to the PC while connected to the USB bus without a battery.
2.4 Audio record and playback
2.4.1 Record
A camera incl ud i ng the STV0 681 wi th a microphone , a compar ator a nd o t her periph ery (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
appro ximation A-D conv erter with 8 bits resolu tion. The SDR AM stores 1 second of audio r ecording
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.
Frequency 50kHz
Frequency 60kHz
Table 2: List of custom sound functions
ADCS 7283313C 13/44
STV0681 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 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.
2 TWAIN driver to suit all TWAIN compatible imaging applications,
3 Video for Microsoft Windows driver for tethered video mode (USB only),
4 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 for m at, running on Microsoft Windows 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 im age do wnload is e xtremel y f ast f or the enti re 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
.
Note: Actual USB download and post processing time also depends on PC performance and USB bus
loading
2.5.2 RS232
Thumbnails of image s , comple te stored images , or th e en tire SDRAM co ntents can be do wnload ed
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 (ar ound 30 seconds for a V GA i mag e), plus post pr ocessing time per image
(of the order of 1 second approximately).
For RS232 interface details, see
Section 4.4
.
Note: Actual post processing time after RS232 download also depends on PC performance
Detailed Features STV0681
14/44 ADCS 7283313C
2.6 Anti-flicker exposure and gain control
2.6.1 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 b utt on is pressed in ‘Snapshot’ mode, the chipset capt ures 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
possibl e. Hence choosing the correct anti -flick er setting is im portant, in order to pr ev ent dark stripes
from appearing across the image, and this selection must be done in hardware.
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 f e w 100 µs in order to correctly e xpose all sensor lines , (contact ST
f or more precise detai ls), theref ore the flashg un module design should h av e reached maximum light
output within this period after the falling edge of the flash trigger output from STV0681.
P ossib le flashgun implementati ons, regard ing hardware interf ace, charge sensing, and flash energ y
required are discussed in a separate application note AN1312 available from STMicroelectronics.
Figure 2: Illustration of flicker problem
Flicker setting not correct Flicker setting correct
ADCS 7283313C 15/44
STV0681 Camera Modes of Operation
3 Camera Modes of Operation
This section refers to the two switches as discussed in section
Section 2.2.1
●“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 giv en mode is displa yed it m ay be selected b y pressing the shutter b utton. 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)
Normal: 20 / 80
Audio Record: Ar
Audio Playback: AP
Delete Last: dA / dP / dC
Continuous Capture: Ct
Self-Timer: St
Clear All: CL
Resolution: Hr / Lr
Notes:
1. Audio Record only available if audio hardware is fitted
2. Audio Playback only available once an audio clip has been recorded
3. DeleteLast 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
Themodeisinhibitedifthecameraisempty.
4. Continuous Capture mode is inhibited when the flashgun is enabled
(SW6 down)
Press Mode button
After 30sec of inactivity
Standby mode (untethered)
Camera Modes of Operation STV0681
16/44 ADCS 7283313C
3.2 Description of modes
3.2.1 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 - usin g 64M bit mem ory) or ‘Lr’ for low r esol ution ( 322 QC IF or 1 07 VGA
images - using 64Mbit memor y) and then displays the number of pictures which may be taken.
Please note that in lo w resolution m ode, al though there can be up to 322 imag es a vailab le , the LCD
counter only goes up to 99, it reports 99 until there are less than 99 images left.
The camera goes back to stand b y mo de after 30 seconds of i nactivity, 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 butt on to take a picture . The camera beeps . A high pitched beep indicates that the
picture w as tak en 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 ti me, whether or not the camer a 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 nor mal 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 but ton within 5 seconds causes the camera to start recordin g 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 stop s because the me mory is ful l, the ‘m emory ful l’ audio tone is sounded and t he displa y
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 shu tter b utton within 5 seconds causes th e camera to pla y ba c k the m ost recent audio
recording. If the shutter b utton is not pre ssed within 5 seconds the camera r ev erts 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.
ADCS 7283313C 17/44
STV0681 Camera Modes of Operation
3.2.5 Delete Last Object - dA/dP/dC
This mode is available with audio record hardware fitted.
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 butto n once causes the camera to beep and ‘dA’, ‘d P’ 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 p ressed down (and the camera is not full). If the shutter b utton 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 contin uous mode, onl y ev ery alternate fiel d is grab bed hence capture r ate is halv ed. F or e xample ,
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, f oll owe d by a longer beep. A f urther beep wil l then indicate that the pictu re has been tak en
(high beep - picture successful, low beep - in suffi cient light, picture not tak en). 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 camer a to beep and the ‘CL’ to start fla shing. Pre ssing
the shutter bu tton again within 5 seconds clears all the i mages/audio clips in the camer a 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 low-
resolution mode) or Lr to change to low-resolution (if currently in high-resolution mode). Press the
shutter b utto n w it hin 5 seconds to sel ect th e r esoluti on o ption, the camer a bee ps and the di splay 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.
STV0681 Hardware Interfaces STV0681
18/44 ADCS 7283313C
4 STV0681 Hardware Interfaces
4.1 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 fur ther details regarding the STV0681-sensor
interface are required.
4.2 Memory interface
STV0681 is designed to interface to an exter nal 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 b y STV0681 , 16MBits (1M x 16 bit s wide) or 64MB its (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 300µA when un-tethered. Meeting this specification, which is included in the requirements for
USB compliance, assumes an SDRAM with up to approximately 250µA self-refresh current, base d
on a current consumption of approximately 50µA for STV0681 + suppor t circuit.
ADCS 7283313C 19/44
STV0681 STV0681 Hardware Interfaces
4.2.2 SDRAM interface timing requirements
Figure 4: SDRAM Read Timing (16Mbit device, burst read)
DCLK
Command
DQM
A0-9,BA
A10
ACTIVE READ NOP PRECHARGE NOP
ROW COLUMN
ROW
DOUT M DOUT M + 1 DOUT M + 2 DOUT M + 3
DQ
READ Latency
tCK
t
RCD
t
RC
CKE
t
RAS
DQ sample DQ sample DQ sample DQ sample
t
RP
tCMS tCMH
tAS tAH
tLtH
tCMS tCMH
t
AC
t
OH
STV0681 Hardware Interfaces STV0681
20/44 ADCS 7283313C
4.2.3 SDRAM refresh period
The SDRAM refresh period from STV0681 is guaranteed to be inferior or equal to 15.6µs 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 981µs in STV0681.
Figure 5: SDRAM Write Timing (16Mbit device, burst write)
Table 3: Timing param eters for SDRAM read/write
Symbol Min. Max Units Symbol Min. Max Units
tCK 166.45 166.89 ns tDS 81.01 ns
tCH ½t
CK tDH 83.41 ns
tCL ½t
CK tRCD 1t
CK
tAC ½t
CK tRAS 55t
CK
tOH 0nst
RC 7t
CK
tCMS 82.88 ns tRP 2t
CK
tCMH 82.85 ns tRCD 1t
CK
tAS 82.88 ns tAH 82.76 ns
DCLK
Command
DQM
A0-9,BA
A10
ACTIVE WRITE NOP PRECHARGE NOP
ROW COLUMN
ROW
DIN M DIN M + 1 DIN M + 2 DIN M + 3
DQ
tCK
t
RCD
t
RC
CKE
t
RAS
t
RP
tCMS tCMH
tAS tAH
tLtH
tCMS tCMH
t
DS
t
DH
ADCS 7283313C 21/44
STV0681 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 ar e:
●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.
STV0681 Hardware Interfaces STV0681
22/44 ADCS 7283313C
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 (ref er to Ref erence Desi gn f or details). Unscreened cab le can be used, a suitab le lo w cost
connector is a 3.5mm stereo audio jack plug.
4.4.2 UART module overview
Receiving data
The UART modu le in STV0681 receiv es serial data th rough the RXD pi n. Dat a recepti on is ini tiated
by a 1-to-0 transition on RXD, and the received data is sampled every 8.66µs.
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 tra nsmission is acti v ated b y STV0681, the conten ts of an i nternal transmit shift re gister are
shifted onto the TXD pin, every 8.66µs.
The U AR T oper ates at 12M Hz, which is not an integ er multip le of 115200 , so the actual b aud 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.
ADCS 7283313C 23/44
STV0681 STV0681 Hardware Interfaces
4.5 Power management and battery type
STV0681 and the SDRAM require a 3.3V supply. When a VV 6411 or VV6501 (3.3 V) 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 ex plained more fully in the reference design.
4.5.1 Power switching to USB
Included in the USB compli ance requirem ents , is the ability of the camera to report to the PC when
connected to the USB bus, whet he r or no t 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.
●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 batter y life.
4.5.3 Battery type
It is possibl e to use v arious battery types and configurations . The evaluation ki t uses f our 1.5V AAA
cells.
STV0681 Hardware Interfaces STV0681
24/44 ADCS 7283313C
4.6 Quartz c rystal
Regardless of the sensor type or anti -f lic ker requirements , the sensor + ST V0681 chipset ope r ates
from a single 12MHz fundamental quar tz 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 multi plex ed, dir ect driv e 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.
ADCS 7283313C 25/44
STV0681 STV0681 Hardware Interfaces
4.8 Switc hes 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
.
Their specific functions are detailed in the reference design and in the following documents
available from ST:
●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 se nsor microphone pream plifi er ), and t he r esul tin g hi gh o r lo w si gnal fr om the comp ar at or
is read a t GPIO4. T he samplin g frequency i s 11kHz, an d the successive appro xim ation is done at 8
bits resolution pe r sample. It is not po ssible 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 lev el thr ough the D A C output, which i s amplified to the speak er
or headphone soc k et. GPIO6 is used to s witch off the ampli fier during periods of audio r ecording, to
prevent the successive appro ximatio n waveform from being hear d during periods of recordin g, and
to reduce the power consumption and unwanted crackle through the speaker.
An actual hardware implementation is given in the audio application note AN1310.
Tabl e 4: Other GPIO usage with STV0681
GPIO 2 4 6 7
Audio Record No Yes No No
Audio
Playback No No Yes No
Flashgun Yes No No Yes
STV0681 Hardware Interfaces STV0681
26/44 ADCS 7283313C
4.9 Flashgun hardware interface
STV0681 will revert to flashgun exposure when it detects GPIO2 is high. Ideally the hardware
should combin e the tw o factors of (a) user inten tion ( e.g. user switches on flashgun) an d (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 s witching on the flashg un charger , and the fla shgun being abl e to fire. To re vert to flashgu n
exposure before the flashgun is completely charged up would cause very bad pictures to be taken
in lo w lig ht con diti on s because ther e i s n o “ low li gh t” thre shold when fla shgun 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 bu tton is pressed, a picture is taken and the
flash trigger pin GPIO7 i s pulse d low at the correct poi nt in time so that all lines of the CM OS 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.
ADCS 7283313C 27/44
STV0681 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).
Alternativ e values f or the VID an d PID as well as Manuf acturer and Product strings ma y 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:
●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
5.1 External EEPROM
An external 128byte serial EEPROM may be used in conjunction with STV0681 to hold customer
specific infor mation.
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 suitabl e
EEPROM device is manufactured by STMicroelectronics part number M24C01W (alternatives are
available from other suppliers).
Customising the STV0681 STV0681
28/44 ADCS 7283313C
5.2 EEPROM data format
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.
Location(decimal) Contents
0 Leave blank
1 VidLo, The low byte of the Vendor ID
2 VidHi, The high byte of the Vendor ID
3 PidLo, The low byte of the Product ID
4 PidHi, The high byte of the Product ID
5 Max Power (in units of 0.5mA)
6 Max Power with audio playback enabled (in units of 0.5mA)
7 Auto powerdown time Hi byte (in units of 256ms)
8 Auto powerdown time Lo byte (in units of 10ms)
9 Mode button press time Hi byte (in units of 256ms)
10 Mode button presss time Lo byte (in units of 10ms)
11 50Hz/60Hz flicker free selection
0 = board link (GPIO3) , 1 = 50Hz, 2 = 60Hz
12 Number of self-timer beeps
13 CheckSum - low byte of sum of EEPROM locations 1 to 12
inclusive.
20 Length of Manufacturer String
21-54 (max) Manufacturer String (ASCII codes)
55 Length of Product String
56-89 (max) Product String (ASCII codes)
90 Length of Interface0 Str ing
91-127 (max) Interface 0 String (ASCII codes)
ADCS 7283313C 29/44
STV0681 Software support
6 Software suppor t
6.1 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 availabl e 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:
●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 do wnload .WAV files from th e PC t o the cam era ( 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 thr ough d emon str ati on software , OEM custom software , o r using stan dar d TWAIN
applications. Features include:
●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 featur es 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:
●Streaming video through standard VfW driver
●Automatic detection and correction of sensor defects
●Colour processing of full image, using the ST colour process
Software support STV0681
30/44 ADCS 7283313C
6.2 Software inst allation
The following software support is only available to OEMs. Access to the latest installation files is
possible through a pass word-protected web page, contact ST f or details. The installation files are f or
the following:
●Drivers (always check the Web site for latest driver version).
●EVK software, i.e. LC DCdemo.exe and AVIcreator.exe, G2Video.exe, and CTItest2.exe
●SDK installation: source code for sample applications, and documentation
6.2.1 Driver support available
6.2.2 EVK software
Note: The f ollo wing is also suppl ied with evalu ation kits/de monstrati on units , b ut all the f ol low ing softw are
is only f or demonstration purposes and should NOT be supplied as an end- user pr oduct. H o wever,
application-level source code (i.e. not driver/colour processing source) for LCDCdemo.exe, AVI
creator, and CTItest.exe i s a v aila bl e as part of the SDK, wh ich allo ws si mila r applicati ons to be b uilt
by the software developer:
1 Simple demonstration software LCDCdemo.exe for uploading thumbnails and images.
2AVIcreator.exe software for uploading continuous images for creating ‘movie’ clips.
3G2Video.exe is a VfW application which shows streaming video while tethered to USB and
allow s creation of.AVI video clips .
4CTItest.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 b y ST as a 32-bit DLL f ormat, running on Mi crosoft Windows 98/Win2 KTM, 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.
Table 5: Driver choices
Interface type: RS232 USB
PC Operating system
Microsoft Windows:
Win9x , Wi nNT4, Win2k,
Windows Millennium
Window s XP
Microsoft Windows:
Win98 and Win2k only,
Windows millenium
Windows X P
Mac OS N/A 8.6, 9.0, 9.1, 9.2
ADCS 7283313C 31/44
STV0681 Detailed Chipset Specifications
7 Detailed Chipset Specifications
7.1 Typical camera specifications
The following data assumes that the camera has been built according to the ST Reference Design.
Dual USB or batter y power supply is only possible when the required powe r switching hardware is
included.
Figures are approximate and depend on actual components sources.
7.2 Absolute maximum ratings
Table 6: Typical camera speci ficati ons
Supply voltage 4.1-6V (when powered from battery or USB)
Operating temperature range 0oC - 40oC
Max. RS232 cab le length supported 2m
CIF output 352 x 288 pixels
QCIF output 176 x 144 pixels
VGA output 640 x 480 pixels
QVGA output 320 x 240 pixels
SDRAM storage and image upload format Raw Bayer
PC driver output format Colour RGB bitmap
Table 7: Approximate shutter speeds
Sensor resolution Min. Max
CIF 8 µs44ms
VGA 8 µs 66 ms
Table 8: STV0681 absolute maximum ratings
Parameter Range Units
Ambient temperature 0 to 40 °C
Storag e tempera ture -50 to 150 °C
Volt age on USB D+/D- 0-VDD V
Detailed Chipset Specifications STV0681
32/44 ADCS 7283313C
7.3 STV0681 specifications
7.4 USB specifications
Note: 1 V
DI
= |(D+) - (D-)|
2V
CM
includes V
DI
range.
3TF
RFM
=(TF
R
/ TF
F
).
4Z
DRV
includes an external resistor of 20 Ohms serial to this transceiver.
Table 9: STV0681 specifications
Parameter Min. Typ. Max. Units
Supply voltage 3.0 3.3 3.6 V
Current consumptio n (normal operation) 18 - mA
Stan d-by current consum pt ion - 10 - µA
Package 100TQ F P (14x14x1 .4)
Exposure control 1 000 000: 1
Table 10: STV0681 USB specifications
Parameter Description Min. Typ. Max. Units Notes
VDD Power Supply 3.0 3.3 3.6 V
VILU USB differential pad D+/D- input low 0.8 V
VIHU USB diffe re ntial pad D+/D- input hig h (d riven) 2.0 V
VIHUZ USB differential pad D+/D- input high (floating) 2.7 3.6 V
VDI USB differential pad D+/D- input sensitivity 0.2 V 1
VCM USB differential pad D+/D- common mode voltage 0.8 2.5 V 2
VOLU USB di fferential pad D+/D- outp ut l ow v ol tage 0. 0 0.3 V
VOHU USB differe ntial pad D+/D- outp ut hi gh vo l tage 2.8 3. 6 V
VCRS USB differential pad D+/D- output signal cross over
voltage 1.51 1.79 V
RPU USB differential pad D+/D- pull up resistor 1.425 1.575 kΩ
RPD USB differential pad D+/D- pull-down resistor 14.25 15.75 kΩ
TFRRise Time 4 20 ns
TFFFall Time 4 20 ns
TFRFM Differential Rise Time and Fall Time Matching 96 98 %
Note 3
ZDRV Driver Output Resistance 24.7 26.6 30.0 Ω
Note 4
ADCS 7283313C 33/44
STV0681 Detailed Chipset Specifications
7.5 DC characteris tics
7.6 PLL characteristic s
7.7 Crystal tolerance
Table 11: STV0681 DC characteristics
Parameter Description Min. Typ. Max. Units
VII CMOS input low voltage 0.35 VDD V
VIH CMOS i nput high voltag e 0.65 VD D V
VT+ CMOS schmi tt input low to high th reshold volt age 2.15 V
VT- CMOS schmitt input high to low threshold voltage 1.05 V
VTThresho l d point 1.65 V
VOH Output high voltage 2.4 V
VOL Output low voltage 0.4 V
Table 12: STV0681 PLL characterist ics
Parameter Conditions Symbol Min. Typ. Max. Unit
Peak to peak jitters @VCOfreq = 240MH z - 312MH z -- -- -- 500 ps
Duty cycle -- 45 50 55 %
Operating voltage range VDD 3 3.3 3.6 V
Input l o w voltage VDD=3.3V VIL - 0.8 V
Input high voltage VDD=3.3V VIH 0.7VDD VDD V
Pull in Time + Locking Time Ready -- -- 0.1 ms
Output Slew Rate CL: Output Load (pF) Tsr(Fout) -- 0.100+0.1082*CL -- ns
Table 13: STV0681 crystal tolerance
Parameter Min. Typ. Max. Units
Crystal specification 50/50/10/30 (12mhz Fundamental)
Crystal frequency 12.000 MHz
Frequen cy toleran ce 50 ppm
Temperature stability 50 ppm
Operating temperature -10 °C
Detailed Chipset Specifications STV0681
34/44 ADCS 7283313C
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
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. 100-250µA
.
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.
Table 14: Current consumption, complete STV0681+VV6411/650 1 camera
Mode Typical Comments
’Snapshot’/Continuous/
Self timer mode
(while un-tethered)
60mA Assuming appropri ate hardw are incl uded, pow er is so urced
from PC while USB connected.
’Snapshot’/Continuous/
Self timer mode
(while tethered to PC)
60mA
While playing back audio
sounds thro ugh speaker 90mA Assuming 8Ω speaker as expl ained in applicat i on note
AN1310
Sta ndby mode
(when NOT connected to
USB)
Approx. 270µA + SDRAM
self-refresh curren t
(see
Note 2
) + sensor
suspend mode current
To tal current in thi s m ode equals:
STV0681 standby current cons um ption (see
Note 1
)
+ SDRAM se l f-refre sh current (see
Note 2
)
+ periphe r al ci rcuitry (approx. 50µA).
+ Sensor suspend mode current
PC Suspend mode
(when connected to USB):
Sensor SUSPEND pin
asserted
Approx. 300µA + SDRAM
self-refresh curren t
(see
Note 2
) + sensor
suspend mode current
To tal current in thi s m ode equals:
STV0681 Standby current consumption (see
Note 1
)
+SDRAM self-refre sh curren t (see
Note 2
)
+ periphe r al ci rcuitry (approx. 50µA)
+ 200µA, based on 1.5k pull-up in camera and 15k pull-
down in PC.
+ Sensor suspend mode current
Sta ndby mode
(when not connected to
USB ): senso r powered off
using FET (see
Note 3
)
Approx. 270µA + SDRAM
self-refresh curren t
(see
Note 2
)
To tal current in thi s m ode equals:
STV0681 Standby current consumption (see
Note 1
)
+SDRAM self-refre sh curren t (see
Note 2
)
+ periphe r al ci rcuitry (approx. 50µA).
PC Suspend mode
(when connected to USB):
sensor powered of f using
FET ( s ee
Note 3
)
Approx. 100µA + SDRAM
self-refresh curren t
(see
Note 2
)
To tal current in thi s m ode equals:
STV0681 Standby current consumption (see
Note 1
)
+SDRAM self-refre sh curren t (see
Note 2
)
+ periphe r al ci rcuitry (approx. 50µA).
ADCS 7283313C 35/44
STV0681 STV0681 pin description
8 STV0681 pin description
8.1 STV0681 pinout
Figure 6: STV0681 pinout diagram
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
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
STV0681
TQFP100
DQ_15
DQ_1
DQ_14
DQ_2
DQ_13
DQ_3
DQ_12
DQ_4
DQ_11
DQ_5
VDD
VSS
DQ_10
DQ_6
DQ_9
DQ_7
DQ_8
DQML
WE
DQMU
CAS
DCLK
RAS
CKE
CS
RESET
XOUT
XIN
TEST2
TEST1
TEST0
USB-
USB+
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
MODE
SHUTTER
FLASH_EN
50/60
COMP_OUT
VSS
VDD
LED
AMP_EN
FL_TRIG
SENSPWR
SENSRST
SENS_CLK
QCLK
SD[0]
SD[1]
SD[2]
SD[3]
SDA
SCL
RXD
TXD
PLL_GVSS
PLL_AVSS
PLL_AVDD
AUD_VSS
LO_BAT_REF
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 pin description STV0681
36/44 ADCS 7283313C
8.2 STV0681 pin description
Table 15: STV0681 pin listing
Pin no. Signal Type Description drive
Sensor Interface
65 SENSPWR Output, active
high Power-up Sensor 2mA
(SL)
64 SENSRST Output, active low Reset Sensor 2mA
(SL)
56 SCL Input/Output
(OD,T) Sensor serial interface 4mA
(SL)
57 SDA Input/Output
(OD,T) Sen sor seri al i nterface 4mA
(SL)
58 SD[3] Input (S,T) Sensor data
59 SD[2] Input (S,T) Sensor data
60 SD[1] Input (S,T) Sensor data
61 SD[0] Input (S,T) Sensor data
62 QCLK Input (S,T) Qualification clock from sensor
63 SENS_CLK Output Clock output to sensor 4mA
I/O and Camera Control pins
75 MODE Debounced inpu t Push button (Wake-up/M ode)
74 SHUTTER Debounced inpu t Push button (Shutt er/Confirm)
73 FLASH_EN Input Enable Flash Exposure (Active High)
72 50 /60_SEL Input S elect between 50Hz and 60Hz lightin g
71 COMP_OUT Input Output from Audio Comparator
68 LE D Outp ut (OD) LED indicator 8mA
(SL)
67 AMP_ENABLE Output, active low
(OD) Audio Amplifier Enable 8mA
(SL)
66 FL_TRIG Output, active low
(OD) Flashgun trigger 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)
USB
specific
ation
V1.1
complia
nt I/O
43 DATA+ Input/Output US B bu s
(For camera with RS232 only, this pin should be
connected to test po ints to al l ow for US B production
test (lens focussing))
44 DATA- Inp ut/Outp ut USB bus.
(For camera with RS232 only, this pin should be
connected to test po ints to al l ow for US B production
test (lens focussing))
ADCS 7283313C 37/44
STV0681 STV0681 pin description
RS232 Interface
54 TXD Output Serial data transmit
(For camera with USB only, this pin should be tied to
RXD)
4mA
(SL)
55 RXD Input (S) Serial dat a receive
(For camera with USB only, this pin should be tied to
TXD)
STV0680B Master Clocks and Reset
48 XIN Input Quartz Cr ystal IN
49 XOUT Ou tp ut Quartz Crystal OUT
50 RESET Input (S) Active (LOW) STV0680B re se t
System Memory (SDRAM) Interface
20 DQMU Output Data input/output mask for dram_DQ[15:8] 2mA
(SL)
22 DCLK Output Clock: all SDRAM input signals are sampled on the
posi ti ve edge 4mA
(SL)
24 CKE Output Clock enable: activates (HIGH) and deactivates
(LOW ) the SDRAM CLK signal 2mA
(SL)
32 AD0 Output SDRAM address A0 2mA
(SL)
34 AD1 Output SDRAM address A1 2mA
(SL)
36 AD2 Output SDRAM address A2 2mA
(SL)
40 AD3 Output SDRAM address A3 2mA
(SL)
41 AD4 Output SDRAM address A4 2mA
(SL)
37 AD5 Output SDRAM address A5 2mA
(SL)
35 AD6 Output SDRAM address A6 2mA
(SL)
33 AD7 Output SDRAM address A7 2mA
(SL)
31 AD8 Output SDRAM address A8 2mA
(SL)
29 AD9 Output SDRAM address A9 2mA
(SL)
30 AD10 Output SDR A M address A1 0 2mA
(SL)
27 AD11 Outpu t SDRAM addr ess A 11 f or 64M SDR AM or BA for 16M
SDRAM 2mA
(SL)
26 AD12 Output SDRAM address A12, BA0 f or 64M SDRAM, unused
on 16M 2mA
(SL)
Table 15: STV0681 pin listing
Pin no. Signal Type Description drive
STV0681 pin description STV0681
38/44 ADCS 7283313C
28 AD13 Output SDRAM address A13, BA1 f or 64M SDRAM, unused
on 16M 2mA
(SL)
25 C S Output, active low Ch i p select: enables (re gistere d LOW) and disables
(registered HIGH) th e SDRAM c om mand de coder. 2mA
(SL)
23 RAS Output, active low SDRAM row address strobe command 2mA
(SL)
21 C AS Output, active low SDRAM column ad dress strobe com mand 2mA
(SL)
19 WE Output, active low SDRA M write enable command 2mA
(SL)
18 DQML Output Data input/output mask for dram_DQ[7:0] 2mA
(SL)
100 DQ0 Input/Output SDRAM Data Bus 2mA
(SL)
2 DQ1 Input/Output SDRAM Data Bus 2mA
(SL)
4 DQ2 Input/Output SDRAM Data Bus 2mA
(SL)
6 DQ3 Input/Output SDRAM Data Bus 2mA
(SL)
8 DQ4 Input/Output SDRAM Data Bus 2mA
(SL)
10 D Q 5 Input /Output SDRAM D a t a B us 2mA
(SL)
14 D Q 6 Input /Output SDRAM D a t a B us 2mA
(SL)
16 D Q 7 Input /Output SDRAM D a t a B us 2mA
(SL)
17 D Q 8 Input /Output SDRAM D a t a bus 2mA
(SL)
15 D Q 9 Input /Output SDRAM D a t a bus 2mA
(SL)
13 DQ10 Input/Output SDRAM Data bus 2 mA
(SL)
9 D Q11 Input/Output SDRA M Data Bu s 2 m A
(SL)
7 D Q12 Input/Output SDRA M Data Bu s 2 m A
(SL)
5 D Q13 Input/Output SDRA M Data Bu s 2 m A
(SL)
3 D Q14 Input/Output SDRA M Data Bu s 2 m A
(SL)
1 D Q15 Input/Output SDRA M Data Bu s 2 m A
(SL)
Table 15: STV0681 pin listing
Pin no. Signal Type Description drive
ADCS 7283313C 39/44
STV0681 STV0681 pin description
LCD Interface
83 LCDCOM Output LCD Common 4mA
(SL)
93 LC D1_6 Outp ut LCD di gi t 1 segment G 2mA
(SL)
94 LC D1_5 Outp ut LCD di gi t 1 segment F 2mA
(SL)
95 LC D1_4 Outp ut LCD di gi t 1 segment E 2mA
(SL)
96 LC D1_3 Outp ut LCD di gi t 1 segment D 2mA
(SL)
97 LC D1_2 Outp ut LCD di gi t 1 segment C 2mA
(SL)
98 LC D1_1 Outp ut LCD di gi t 1 segment B 2mA
(SL)
99 LC D1_0 Outp ut LCD di gi t 1 segment A 2mA
(SL)
86 LC D2_6 Outp ut LCD di gi t 2 segment G 2mA
(SL)
87 LC D2_5 Outp ut LCD di gi t 2 segment F 2mA
(SL)
88 LC D2_4 Outp ut LCD di gi t 2segment E 2mA
(SL)
89 LC D2_3 Outp ut LCD di gi t 2segment D 2mA
(SL)
90 LC D2_2 Outp ut LCD di gi t 2segment C 2mA
(SL)
91 LC D2_1 Outp ut LCD di gi t 2 segment B 2mA
(SL)
92 LC D2_0 Outp ut LCD di gi t 2 segment A 2mA
(SL)
Piezo Interface
82 P I EZO Output Direct connec tion to pi ezo buzzer 8mA
(SL)
Battery Level Comparator Interface
78 LO_BAT Input (A) Battery level comparator input. The voltage on
low_b at is compared to the r efer ence to determine
the battery status
77 LO_BAT_REF Input (A) 1.22V battery level comparator reference input
Table 15: STV0681 pin listing
Pin no. Signal Type Description drive
STV0681 pin description STV0681
40/44 ADCS 7283313C
Note: 1
Where the I/O pad type is not explicitly defined, assume CMOS.
Power and Ground
12, 38,
70, 84 DVSS Power pin Digital Ground
11, 39,
69, 85 DVDD Power pin Digital Power
76 AUD_VSS Power pin Audio DAC Ground. Requires clean suppl y.
81 AUD_VDD Power pin Audio DAC Power. Requir es clean supply.
53 PLLGVSS Powe r pi n PLL Gu ard Ground
51 P LLAVD D Power pin PLL Analog Power
52 P LLAVSS Power pin PLL Analo g Ground
Non-user pins
45 TE S T 0 Input Non-use r pi n - connec t to 3V3
46 TE S T 1 Input Non-use r pi n - connec t to 3V3
47 TE S T 2 Input Non-use r pi n - connec t to 3V3
79 DACRES I(A) DAC bias amp lifier reference input.
80 DACOUT O (A) 8-bit DAC current source output. 0-10mA
Key
SL slew rate lim i ted output
OD open drain ou tput
S Schmidt input
A analogue i nput/output
T 5V tolerant pad (these pads do not have diode protection)
Table 15: STV0681 pin listing
Pin no. Signal Type Description drive
ADCS 7283313C 41/44
STV0681 STV0681 package mechanical data
9 STV0681 packa ge mechanical data
TQFP100
Dim. mm inch
Min. Typ. Max. Min. Typ. Max.
A1.600.063
A1 0.05 0.15 0.002 0.006
A2 1.35 1.40 1.45 0.053 0.055 0.057
B 0.17 0.22 0.27 0.007 0.009 0.011
C 0.09 0.20 0.003 0.008
D 16.00 0.630
D1 14.00 0.551
D3 12.00 0.472
e0.50 0.019
E 16.00 0.630
E1 14.00 0.551
E3 12.00 0.472
L 0.45 0.60 0.75 0.018 0.024 0.030
L1 1.00 0.039
3
K 3.5° (min.), 7° (max.)
A
A2
A1
Seating Plane
C
50
5175
76
D3
D1
D
e
TQFP100M
0.076mm
.003 inch
K
L
L1
Pin 1
identification
100 1
B
25 26
EE1E3
Evaluation Kit (EVK) STV0681
42/44 ADCS 7283313C
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 memo ry, connectors, n umeric LCD display, battery holder , push b uttons/s witches,
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
Note:
All Ev aluation Kits inclu de hardw are and softwar e support f or A udio , C ustom sounds, and F lashgun
features.
Table 16: Ordering details for STV0681 + VV6411/6501 Evaluation Kits
Description Part number
STV0681 companion processor STV0681
VV64 11 CIF colo r CMOS sens or (36LCC package) VV6 411C036
VV65 01 VGA color CMOS sensor (3 6LCC packag e) V V6501C 001
Complete Evaluation Kit
STV0681 complete Evaluation Kit
(includes STV-681-M01, STV-6411C-D01 and STV6501C-D01) STV-681-E01
Additional EVK Components
Evaluation Kit Motherboard STV-681-M01
Senso r Daughter Board with V V6411 STV-6411C-D 01
Senso r Daughter Board with V V6501 STV-6501C-D 01
ADCS 7283313C 43/44
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 44/44
STV0681
Information furnished is believed to be accura te and reliable . How e ve r , ST Microelectronics assumes no responsibility for th e consequences
of use of suc h information nor for any infringe m ent of patents or other rig hts of third partie s whic h 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 pu b lic at ion 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.
The ST l ogo is a regi s tered trademark of STMicroe l ectronic s
© 2003 STMicroelectronics - Al l Rights R e s erved
STMicroelectronics GROUP OF COMPANIES
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