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STV0681

DUAL-MODE DIGITAL CAMERA CO-PROCESSOR

DESCRIPTION

● Quick Power Down (by holding Mode Button).

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.

● “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.

FEATURES

ST have maintained the standard features already

available in the successful STV068B chipset,

including:

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.

● 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.

Recorded audio sounds can also be played back on

the camera, with the addition of an amplifier chip

and speaker or headphone socket.

● High frame rate web cam (tethered video)

over USB.

● Audio record/playback and “Delete Last”

function

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).

● 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.

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).

● 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

Note: Simultaneous audio record and

continuous video capture is not possible.

● 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.

March 2003

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STV0681

Table of Contents

Chapter 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Digital camera chipset ..........................................................................................................5

Key system features .............................................................................................................6

1.1

1.2

Chapter 2

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

2.1

2.2

2.3

2.4

2.5

2.6

Chapter 3

Camera Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Modes available .................................................................................................................15

Description of modes .........................................................................................................16

3.1

3.2

Chapter 4

4.1

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

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

4.10

Chapter 5

Customising the STV0681 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

External EEPROM .............................................................................................................27

EEPROM data format ........................................................................................................28

Programming the EEPROM ...............................................................................................28

5.1

5.2

5.3

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Chapter 6

Software support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

General features ................................................................................................................29

Software installation ...........................................................................................................30

6.1

6.2

Chapter 7

7.1

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

7.2

7.3

7.4

7.5

7.6

7.7

7.8

Chapter 8

STV0681 pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

STV0681 pinout .................................................................................................................35

STV0681 pin description .................................................................................................... 36

8.1

8.2

Chapter 9

STV0681 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Chapter 10 Evaluation Kit (EVK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

10.1

10.2

Ordering details ..................................................................................................................42

Technical support ...............................................................................................................43

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STV0681

Document Revision History

Revision

Draft

1.0

Date

Comments

Initial release (product preview)

A

May 2001

April 2002

B

C

4.0

Document status updated to datasheet.

Major changes: removed references of VV6410 and VV6444

sensors

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)

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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

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

STV0681

1.1.6 “Delete Last” function

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

LED

Flashgun

Enable/Trigger

Audio

Speaker

2 x 7 seg. LCD

Push

Buttons:

“Shutter

/Record”

Amplifier

“Mode”

CMOS Sensor

VV6411 (CIF)

Microphone

OEM Flashgun

Module

Comparator

VV6501 (VGA)

16MBit or 64MBit

SDRAM

GPIO

LCD

Driver

memory

I/F

Enable/Trigger

Audio DAC

Audio

Pre-Amp

RS232 interface

to PC

RS232

I/F

Transceiver

Sensor data

Sensor

I/F

Circuit (Discretes)

STV0681

Sensor clock

USB

I/F

Detect Low

Battery

Image Array

VReg

Power

Management

Circuit (Discretes)

USB interface

to PC

Piezo

Buzzer

PWM

4.5 - 6v Battery e.g.

3-4 x AA, AAA, etc.

12MHz XTAL

Lens +

IR Filter

Subject

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 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

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 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.

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.

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Introduction

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● 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 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.

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Detailed Features

2

Detailed Features

2.1

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 Windows 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.

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

(“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 Max. no. of

images

stored in

16MBit

memory

(Note 2)

images

stored in

64MBit

memory

(Note 2)

Approximate

VfW framerate

(Note 1)

Sensor

Image Size

Resolution

mode

Final Image Size

CIF 352 x 288

VGA 640 x 480

High

Low

CIF 352 x 288

20

80

15 frames/sec.

QCIF 176 x 144

(Subsampled)

322

22.5 frames/sec.

(see Note 3)

High

Low

VGA 640 x 480

(6)

26

2 frames/sec.

12 frames/sec.

QVGA 320 x 240

(Subsampled)

(26)

107

(see Note 3)

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.

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 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.

Note: 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

2.2.4 Piezo buzzer

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

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

3

4

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.

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

7

End of continuous capture in un-tethered ‘Continuous’ mode due to full memory.

Self-timer activated, count down has started.

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

STV0681

Table 2: List of custom sound functions

Frequency 50kHz

Frequency 60kHz

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.

Note: 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

Audio record and playback

2.4.1 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

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

3

4

TWAIN driver to suit all TWAIN compatible imaging applications,

Video for Microsoft Windows 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 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 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.

Note: 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.

Note: Actual post processing time after RS232 download also depends on PC performance

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Detailed Features

STV0681

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 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 µs 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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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 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

After 30sec of inactivity

Standby mode (untethered)

Normal: 20 / 80

Audio Record: Ar

Audio Playback: AP

Delete Last: dA / dP / dC

Continuous Capture: Ct

Self-Timer: St

Notes:

1. Audio Record only available if audio hardware is fitted

2. Audio Playback only available once an audio clip has been recorded

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)

Clear All: CL

Resolution: Hr / Lr

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Camera Modes of Operation

STV0681

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 - 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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ADCS 7283313C

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 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 low-

resolution 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

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 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 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, based

on a current consumption of approximately 50µA for STV0681 + support circuit.

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ADCS 7283313C

STV0681

STV0681 Hardware Interfaces

4.2.2 SDRAM interface timing requirements

Figure 4: SDRAM Read Timing (16Mbit device, burst read)

t

CK

t

L

H

DCLK

CKE

t

CMS

CMH

READ

Command

A0-9,BA

ACTIVE

ROW

NOP

PRECHARGE

NOP

COLUMN

A10

ROW

t

CMS

AS

AH

t

CMH

t

OH

t

AC

DQM

DQ

DOUT M

DOUT M + 1

DOUT M + 2

DOUT M + 3

t

RCD

READ Latency

t

RC

t

RP

RAS

DQ sample

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STV0681 Hardware Interfaces

STV0681

Figure 5: SDRAM Write Timing (16Mbit device, burst write)

t

CK

t

L

H

DCLK

CKE

t

CMS

CMH

WRITE

Command

A0-9,BA

ACTIVE

ROW

NOP

PRECHARGE

NOP

COLUMN

A10

ROW

t

AS

AH

CMS

t

CMH

t

DH

DS

DQM

DQ

DIN M

DIN M + 1

DIN M + 2

DIN M + 3

t

RCD

t

RC

t

RP

RAS

Table 3: Timing parameters for SDRAM read/write

Symbol

Min.

Max

Units

Symbol

Min.

Max

Units

t

166.45

166.89

ns

t

81.01

ns

CK

DS

DH

½

t

83.41

CH

CK

t

1

t

CL

RCD

CK

½

t

5

t

AC

RAS

0

ns

t

7

2

OH

CMS

CMH

AS

RC

82.88

82.85

82.88

t

RP

t

1

RCD

t

82.76

ns

AH

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.

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ADCS 7283313C

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 are:

● 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 Hardware Interfaces

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 8.66µs.

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 transmission is activated by STV0681, the contents of an internal transmit shift register are

shifted onto the TXD pin, every 8.66µs.

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

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.

● 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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ADCS 7283313C

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

2

4

6

7

Audio Record

No

Yes

No

Audio

Yes

Playback

Flashgun

Yes

No

Yes

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 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 Hardware Interfaces

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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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).

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:

● 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 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)

Contents

0

Leave blank

1

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)

2

3

4

5

6

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)

7

8

9

10

11

50Hz/60Hz flicker free selection

0 = board link (GPIO3) , 1 = 50Hz, 2 = 60Hz

12

13

Number of self-timer beeps

CheckSum - low byte of sum of EEPROM locations 1 to 12

inclusive.

20

Length of Manufacturer String

Manufacturer String (ASCII codes)

Length of Product String

21-54 (max)

55

56-89 (max)

90

Product String (ASCII codes)

Length of Interface0 String

91-127 (max)

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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ADCS 7283313C

STV0681

Software support

6

Software support

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 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:

● 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:

● 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:

● 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:

● 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

RS232

USB

Interface type:

Microsoft Windows

:

Microsoft Windows

Win98 and Win2k only,

Windows millenium

Windows XP

:

Win9x, WinNT4, Win2k,

Windows Millennium

Windows XP

PC Operating system

N/A

8.6, 9.0, 9.1, 9.2

Mac OS

6.2.2 EVK software

Note: 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

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.

4

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.

TM

The SDK is supplied by ST as a 32-bit DLL format, running on Microsoft Windows 98/Win2K , 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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ADCS 7283313C

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 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

4.1-6V (when powered from battery or USB)

Supply voltage

o

0 C - 40 C

Operating temperature range

Max. RS232 cable length supported

CIF output

2m

352 x 288 pixels

176 x 144 pixels

640 x 480 pixels

320 x 240 pixels

Raw Bayer

QCIF output

VGA output

QVGA output

SDRAM storage and image upload format

PC driver output format

Colour RGB bitmap

Table 7: Approximate shutter speeds

Min.

Sensor resolution

Max

CIF

8 µs

44 ms

66 ms

VGA

8 µs

7.2

Absolute maximum ratings

Table 8: STV0681 absolute maximum ratings

Parameter

Range

Units

Ambient temperature

Storage temperature

Voltage on USB D+/D-

0 to 40

-50 to 150

0-VDD

°C

V

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Detailed Chipset Specifications

STV0681

7.3

STV0681 specifications

Table 9: STV0681 specifications

Parameter

Min.

Typ.

Max.

Units

Supply voltage

3.0

3.3

18

10

3.6

V

Current consumption (normal operation)

Stand-by current consumption

Package

-

mA

µA

-

100TQFP (14x14x1.4)

1 000 000: 1

Exposure control

7.4

USB specifications

Table 10: STV0681 USB specifications

Parameter

VDD

Description

Min.

Typ.

Max. Units Notes

Power Supply

3.0

3.3

3.6

0.8

V

USB differential pad D+/D- input low

ILU

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

2.0

2.7

0.2

0.8

0.0

2.8

1.51

V

IHU

IHUZ

DI

3.6

1

2

2.5

0.3

CM

OLU

OHU

CRS

3.6

USB differential pad D+/D- output signal cross over

voltage

1.79

R

USB differential pad D+/D- pull up resistor

USB differential pad D+/D- pull-down resistor

Rise Time

1.425

14.25

4

1.575

15.75

20

kΩ

ns

%

PU

PD

TF

R

Fall Time

4

20

F

Differential Rise Time and Fall Time Matching

Driver Output Resistance

96

98

Note 3

Note 4

RFM

Z

24.7

26.6

30.0

Ω

DRV

Note: 1 V = |(D+) - (D-)|

DI

2 V

includes V range.

DI

CM

3 TF

=(TF / TF ).

R F

RFM

4 Z

includes an external resistor of 20 Ohms serial to this transceiver.

DRV

32/44

ADCS 7283313C

STV0681

Detailed Chipset Specifications

7.5

DC characteristics

Table 11: STV0681 DC characteristics

Parameter

Description

CMOS input low voltage

Min.

Typ.

Max.

Units

V

0.35 VDD

V

II

CMOS input high voltage

0.65 VDD

IH

T+

T-

CMOS schmitt input low to high threshold voltage

CMOS schmitt input high to low threshold voltage

Threshold point

2.15

1.05

1.65

T

Output high voltage

2.4

OH

OL

Output low voltage

0.4

7.6

PLL characteristics

Table 12: STV0681 PLL characteristics

Parameter

Conditions

Symbol

Min.

Typ.

Max. Unit

Peak to peak jitters

Duty cycle

@VCOfreq = 240MHz - 312MHz

--

500

55

ps

%

V

45

50

3.3

Operating voltage range

Input low voltage

VDD

VIL

3

3.6

0.8

VDD

0.1

--

VDD=3.3V

-

V

Input high voltage

Pull in Time + Locking Time

Output Slew Rate

VIH

0.7VDD

V

Ready

Tsr(Fout)

--

ms

ns

CL: Output Load (pF)

0.100+0.1082*CL

7.7

Crystal tolerance

Table 13: STV0681 crystal tolerance

Parameter

Min.

Typ.

Max.

Units

Crystal specification

Crystal frequency

50/50/10/30 (12mhz Fundamental)

12.000

MHz

ppm

°C

Frequency tolerance

Temperature stability

Operating temperature

50

-10

ADCS 7283313C

33/44

Detailed Chipset Specifications

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

Typical

Comments

’Snapshot’/Continuous/

Self timer mode

60mA

Assuming appropriate hardware included, power is sourced

from PC while USB connected.

(while un-tethered)

’Snapshot’/Continuous/

Self timer mode

(while tethered to PC)

60mA

90mA

While playing back audio

sounds through speaker

Assuming 8Ω speaker as explained in application note

AN1310

Standby mode

Approx. 270µA + SDRAM Total current in this mode equals:

self-refresh current

(when NOT connected to

USB)

STV0681 standby current consumption (see Note 1)

(see Note 2) + sensor

suspend mode current

+ SDRAM self-refresh current (see Note 2)

+ peripheral circuitry (approx. 50µA).

+ Sensor suspend mode current

PC Suspend mode

Approx. 300µA + SDRAM Total current in this mode equals:

self-refresh current

(when connected to USB):

Sensor SUSPEND pin

asserted

STV0681 Standby current consumption (see Note 1)

(see Note 2) + sensor

suspend mode current

+SDRAM self-refresh current (see Note 2)

+ peripheral circuitry (approx. 50µA)

+ 200µA, based on 1.5k pull-up in camera and 15k pull-

down in PC.

+ Sensor suspend mode current

Standby mode

Approx. 270µA + SDRAM Total current in this mode equals:

self-refresh current

(when not connected to

USB): sensor powered off

using FET (see Note 3)

STV0681 Standby current consumption (see Note 1)

(see Note 2)

+SDRAM self-refresh current (see Note 2)

+ peripheral circuitry (approx. 50µA).

PC Suspend mode

Approx. 100µA + SDRAM Total current in this mode equals:

self-refresh current

(when connected to USB):

sensor powered off using

FET (see Note 3)

STV0681 Standby current consumption (see Note 1)

(see Note 2)

+SDRAM self-refresh current (see Note 2)

+ peripheral circuitry (approx. 50µA).

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.

34/44

ADCS 7283313C

STV0681

STV0681 pin description

8

STV0681 pin description

8.1

STV0681 pinout

Figure 6: STV0681 pinout diagram

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

100

RESET

XOUT

XIN

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

LO_BAT

DACRES

DACOUT

AUD_VDD

PIEZO

TEST2

TEST1

TEST0

USB-

LCD_COM

VSS

USB+

USB_DET

AD_4

AD_3

VDD

STV0681

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

VSS

TQFP100

AD_5

AD_2

AD_6

AD_1

AD_7

AD_0

AD_8

AD_10

AD_9

AD_13

AD_11

AD_12

ADCS 7283313C

35/44

STV0681 pin description

STV0681

8.2

STV0681 pin description

Table 15: STV0681 pin listing

Type Description

Pin no.

Signal

drive

Sensor Interface

65

64

56

57

SENSPWR

Output, active

high

Power-up Sensor

2mA

(SL)

SENSRST

SCL

Output, active low Reset Sensor

2mA

(SL)

Input/Output

(OD,T)

Sensor serial interface

4mA

(SL)

SDA

Input/Output

(OD,T)

Sensor serial interface

4mA

(SL)

58

59

60

61

62

63

SD[3]

Input (S,T)

Output

Sensor data

SD[2]

Sensor data

SD[1]

Sensor data

SD[0]

Sensor data

QCLK

Qualification clock from sensor

Clock output to sensor

SENS_CLK

4mA

I/O and Camera Control pins

75

74

73

72

71

68

MODE

Debounced input

Input

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

SHUTTER

FLASH_EN

50/60_SEL

COMP_OUT

LED

Input

Output (OD)

8mA

(SL)

67

66

AMP_ENABLE Output, active low

(OD)

Audio Amplifier Enable

Flashgun trigger

8mA

(SL)

FL_TRIG

Output, active low

(OD)

8mA

(SL)

USB Interface

42

USBDET

Input (S)

Detect Power source from USB.

USB

specific

ation

V1.1

(For camera with RS232 only, this pin should be tied

to GND)

43

DATA+

DATA-

Input/Output

USB bus

complia

nt I/O

(For camera with RS232 only, this pin should be

connected to test points to allow for USB production

test (lens focussing))

44

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))

36/44

ADCS 7283313C

STV0681

STV0681 pin description

Table 15: STV0681 pin listing

Type Description

Pin no.

Signal

drive

RS232 Interface

54

55

TXD

RXD

Output

Serial data transmit

4mA

(SL)

(For camera with USB only, this pin should be tied to

RXD)

Input (S)

Serial data receive

(For camera with USB only, this pin should be tied to

TXD)

STV0680B Master Clocks and Reset

48

49

50

XIN

Input

Quartz Crystal IN

XOUT

RESET

Output

Input (S)

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

Output

Data input/output mask for dram_DQ[15:8]

2mA

(SL)

Clock: all SDRAM input signals are sampled on the

positive edge

4mA

(SL)

Clock enable: activates (HIGH) and deactivates

(LOW) the SDRAM CLK signal

2mA

(SL)

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

2mA

(SL)

AD1

2mA

(SL)

AD2

2mA

(SL)

AD3

2mA

(SL)

AD4

2mA

(SL)

AD5

2mA

(SL)

AD6

2mA

(SL)

AD7

2mA

(SL)

AD8

2mA

(SL)

AD9

2mA

(SL)

AD10

AD11

AD12

2mA

(SL)

SDRAM address A11 for 64M SDRAM or BA for 16M

SDRAM

2mA

(SL)

SDRAM address A12, BA0 for 64M SDRAM, unused

on 16M

2mA

(SL)

ADCS 7283313C

37/44

STV0681 pin description

STV0681

Table 15: STV0681 pin listing

Pin no.

28

Signal

Type

Output

Description

drive

AD13

SDRAM address A13, BA1 for 64M SDRAM, unused

on 16M

2mA

(SL)

25

23

21

19

18

100

2

CS

Output, active low Chip select: enables (registered LOW) and disables

(registered HIGH) the SDRAM command decoder.

2mA

(SL)

RAS

CAS

WE

Output, active low SDRAM row address strobe command

Output, active low SDRAM column address strobe command

Output, active low SDRAM write enable command

2mA

(SL)

2mA

(SL)

2mA

(SL)

DQML

DQ0

DQ1

DQ2

DQ3

DQ4

DQ5

DQ6

DQ7

DQ8

DQ9

DQ10

DQ11

DQ12

DQ13

DQ14

DQ15

Output

Data input/output mask for dram_DQ[7:0]

SDRAM Data Bus

SDRAM Data bus

SDRAM Data Bus

2mA

(SL)

Input/Output

2mA

(SL)

2mA

(SL)

4

2mA

(SL)

6

2mA

(SL)

8

2mA

(SL)

10

14

16

17

15

13

9

2mA

(SL)

2mA

(SL)

2mA

(SL)

2mA

(SL)

2mA

(SL)

2mA

(SL)

2mA

(SL)

7

2mA

(SL)

5

2mA

(SL)

3

2mA

(SL)

1

2mA

(SL)

38/44

ADCS 7283313C

STV0681

STV0681 pin description

Table 15: STV0681 pin listing

Type Description

Pin no.

Signal

drive

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

LCD Common

4mA

(SL)

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

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

77

LO_BAT_REF

Input (A)

1.22V battery level comparator reference input

ADCS 7283313C

39/44

STV0681 pin description

STV0681

Table 15: STV0681 pin listing

Type Description

Pin no.

Signal

drive

Power and Ground

12, 38,

70, 84

DVSS

Power pin

Digital Ground

Digital Power

11, 39,

69, 85

DVDD

76

81

53

51

52

AUD_VSS

AUD_VDD

PLLGVSS

PLLAVDD

PLLAVSS

Power pin

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

Input

I(A)

Non-user pin - connect to 3V3

DAC bias amplifier reference input.

8-bit DAC current source output.

TEST1

TEST2

DACRES

DACOUT

O (A)

0-10mA

Key

SL

OD

S

slew rate limited output

open drain output

Schmidt input

A

analogue input/output

T

5V tolerant pad (these pads do not have diode protection)

Note: 1 Where the I/O pad type is not explicitly defined, assume CMOS.

40/44

ADCS 7283313C

STV0681

STV0681 package mechanical data

9

STV0681 package mechanical data

mm

inch

Dim.

Min.

Typ.

Max.

Min.

Typ.

Max.

A

1.60

0.15

1.45

0.27

0.20

0.063

0.006

0.057

0.011

0.008

A1

A2

B

0.05

1.35

0.17

0.09

0.002

0.053

0.007

0.003

1.40

0.22

0.055

0.009

C

D

16.00

14.00

12.00

0.50

0.630

0.551

0.472

0.019

0.630

0.551

0.472

0.024

D1

D3

e

E

16.00

14.00

12.00

0.60

E1

E3

L

0.45

0.75

0.018

0.030

TQFP100

L1

1.00

0.039

3

K

3.5° (min.), 7° (max.)

D

A

D1

D3

A2

A1

75

51

76

50

0.076mm

.003 inch

Seating Plane

e

E3 E1

E

B

Pin 1

identification

26

100

25

1

K

C

TQFP100M

L

L1

ADCS 7283313C

41/44

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 Part number

STV0681 companion processor

STV0681

VV6411 CIF color CMOS sensor (36LCC package)

VV6501 VGA color CMOS sensor (36LCC package)

Complete Evaluation Kit

VV6411C036

VV6501C001

STV0681 complete Evaluation Kit

STV-681-E01

(includes STV-681-M01, STV-6411C-D01 and STV6501C-D01)

Additional EVK Components

Evaluation Kit Motherboard

STV-681-M01

STV-6411C-D01

STV-6501C-D01

Sensor Daughter Board with VV6411

Sensor Daughter Board with VV6501

Note: All Evaluation Kits include hardware and software support for Audio, Custom sounds, and Flashgun

features.

42/44

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

43/44

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.

The ST logo is a registered trademark of STMicroelectronics

STMicroelectronics GROUP OF COMPANIES

Australia - Brazil - Canada - China - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan

Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A.

www.st.com

ADCS 7283313C

44/44

型号:	VV6501C001
是否Rohs认证：	符合
生命周期：	Obsolete
IHS 制造商：	STMICROELECTRONICS
零件包装代码：	LCC
包装说明：	LCC-36
针数：	36
Reach Compliance Code：	compliant
HTS代码：	8542.39.00.01
风险等级：	5.81
Is Samacsys：	N
模拟集成电路 - 其他类型：	ANALOG CIRCUIT
JESD-30 代码：	S-XQCC-N36
湿度敏感等级：	3
功能数量：	1
端子数量：	36
最高工作温度：	40 °C
最低工作温度：
封装主体材料：	UNSPECIFIED
封装代码：	QCCN
封装形状：	SQUARE
封装形式：	CHIP CARRIER
峰值回流温度（摄氏度）：	250
认证状态：	Not Qualified
子类别：	Other Analog ICs
最大供电电压 (Vsup)：	5.5 V
最小供电电压 (Vsup)：	4.1 V
标称供电电压 (Vsup)：	5 V
表面贴装：	YES
技术：	CMOS
温度等级：	COMMERCIAL
端子形式：	NO LEAD
端子位置：	QUAD
处于峰值回流温度下的最长时间：	NOT SPECIFIED
Base Number Matches：	1

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