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
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.
ADCS 7283313C
5/44
STMICROELECTRONICS [ ST ]
