March 2003
ADCS 7283313C
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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 dual-
mode 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:
q
Support for VV6411 (CIF) and VV6501 (VGA)
CMOS imaging sensors.
q
Support for SDRAM sizes 16MBit (up to 20
CIF images) or 64Mbit (up to 80 CIF or 26
VGA images).
q
Low resolution "economy" mode allows for
more images to be stored.
q
High frame rate web cam (tethered video)
over USB.
q
Audio record/playback and "Delete Last"
function
q
Custom sounds playback (e.g. "Talking" or
"Musical" camera)
q
Support for an OEM Flashgun module
q
Automatic anti-flicker exposure control.
q
Image up load over RS232 or USB.
q
Driver support for Win98/Win2k/WinME and
MacOS 8.6/9.0/9.1.
q
Continuous capture while untethered (except
when Flashgun enabled) and downloading to
AVI file format
q
Power-saving "stand-by" mode which
maintains memory contents.
q
Simple user interface including 2 buttons,
status LCD display, and buzzer.
q
Evaluation Kit (EVK) available.
q
Software Development Kit (SDK) allows OEM
PC Software applications to be written.
q
Quick Power Down (by holding Mode Button).
q
"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
).
Note:
Simultaneous audio record and
continuous video capture is not possible.
STV0681
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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
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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
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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
C
4.1
November
2002
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)
ADCS 7283313C
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STV0681
Introduction
1
Introduction
1.1
Digital camera chipset
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 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 Windows
TM
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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