Vision VV6500C001, VV6444C001, VV6410C036, STV-DCA-VGA-E01, STV-DCA-CIF-E01 Datasheet

STV0680A + VV6444/6410/6500

®

Low Cost Digital Camera (LCDC) Chipset

PRELIMINARY

DESCRIPTION

STMicroelectronics (ST), Imaging Division (formerly VLSI
VISION Ltd.), has utilised its extensive experience in design­ing imaging sensors for the digital still camera market to
develop chipsets for modular systems which wi ll provide the
core of a highly cost-competitive new standard in consumer
digital stills cameras (DSC).

The Low Cost Digital Camera chipsets from ST, incorporat­ing a CMOS imaging sensor and STV0680A co-processor
(formerly DCA1 ) enable camera manufacturers to offer an
end product which is genuinely price competitive with tradi­tional ‘point and shoot’ film-based cameras.

The chipset provides the basis of an easy-to-use, user
friendly camera, which will be equally adaptable for use by
children and adults for stills photography or dual-mode use
(i.e. Digital stills while untethered, and videoconferencing
from the same camera).

Incorporating a wide range of features, the STV0680A
chipset offers exc ep tion al performance at a very co mp etit iv e
price point. ST’s aim is to enable manufacturers to offer fully
functional DSC products to the end consumer for between
$50 and $100. An evaluati on k it (EVK) a nd re fere nce des ig n
manual are availab le, a s wel l as sta ndard TWAIN and Video
for Windows drivers. Alternative ly, a software development
kit (SDK) allows access to ST colour processing algorithms
under licence, to develop OEM software.

The chipset incorporates ST’s high performance VV6444/
6410 CIF (352 x 288 pix el) or VV65 00 VGA (640 x 480 pi xel)
resolution CMOS sensors. The complete camera will have
20 picture storage capacity for CIF resolution or 80 for QCIF
resolution, when using 16MBit memory. When using 64MBit
memory, it will have 26 picture storage capacity for VGA res­olution or 106 for QVGA resolution. A standby mode which
allows full picture retention at extremely low system power
consumption gives a battery life of up to several months.

An example upload and colour processing time for a CIF
image to the PC is 0.3 seconds when the USB interface is
used, and the chipset also offers a high frame rate tethered
USB video mode (dependant on PC and USB loading).

The chipset supports a 2x 7-segment display showing num­ber of pictures remaining, a low battery indicator, and opera­tion mode, as well as a buzzer indicating picture taken,
camera full, and self-timer countdown.

A CMOS solution gives manufacturers inherent benefits, pro­viding a highly integrated compact solution which has a low
system cos t, is straightforward to implement , and has low
power consumption, giving long battery life.

KEY FEATURES

• CIF (352 x 288) or VGA (640 x 480) resolution sensor

• Using 64MBit memory, 80 picture storage capacity in
camera (CIF), 26 (VGA), or 320 (QCIF).

• Using 16MBit memory, 20 picture storage capacity, in
camera (CIF), or 80 (QCIF)

• USB/RS232 inte rfa ce opti on s

• Evaluation kit available

• Low power consumption (typically 75mA) for complete
camera and low system cost per pixel

• High speed picture upload with USB

• USB tethered video mode gives a QCIF resolution
videoconferencing camera with VfW support

• ‘Continuous’ mode for capturing image sequences (while
untethered) and downloading to AVI file format

• Memory refresh allows picture retention when camera is
in standby mode with very low current consumption

• TWAIN/Video for Windows driver support

• Numeric LCD panel supported

• Colour processing and pixel defect detection/correction
software available under license as SDK for development
of OEM software. The license to use the colour algorithm
(embedded in the PC driver software) is included in the
price of the chipset.

PRODUCT FORMATS

Chipsets: For manufacturers wishing to design their own
cameras ST offers chipsets combining the colour CMOS
sensor with a companion processor.

An evaluation kit, including PC demo software, and a
comprehensive reference design manual are available,
including schematics and bills of materials.

Modules
modules are available to the basic specification outlined, but
geared to the customer’s individual requirements, subject to
commercial agreement with ST.

: For high volume OEM companies, lensed camera

SOFTWARE

Driver software is available to support both USB and RS232
interface, included in TWAIN and Video for Windows drivers
(VfW through USB only, WIN98). An AVI creator application
allows creation of video files from untethered ‘continuous’
mode images.

ST colour processing and defect detection/correction
software is supplied under licence agreement, as part of a
Software Development Kit (SDK). This runs on the host PC

under either Windows95

TM

or Windows98TM .

CDSTV0680F-C: Rev 3.0; Mar.2000

This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

Commercial in Confidence

1

PRELIMINARY

Digital Camera Chipset; Customer Datasheet, Rev 3.0,

March 2000

STV0680A + VV6444/6410/6500

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.1 Digital camera chipset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

1.2 Co-processor choices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.3 Sensor choices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

1.4 Key system features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

1.4.1 Image features (STV0680A-002). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.2 Image features (STV0680-001). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.3 User features on camera. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

1.4.4 User features on PC software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

1.4.5 Power management features and USB compliance . . . . . . . . . . . . . . . . . . . . . . . . . .9

1.4.6 General features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

2. Detailed features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.1 Sensor type and image formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.1.1 VV6444 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.1.2 VV6410 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.1.3 VV6500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2 User interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.2.1 Push buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.2.2 LED indicator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.2.3 Picture counter using 2 x 7 segment display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.2.4 Piezo buzzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.3 Battery Level Detect and USB auto-switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.4 PC interface options and software support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2

2.4.1 USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.4.2 RS232 (not available on STV0680-001) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.5 Anti-flicker exposure and gain control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

3. Camera modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

3.1 Standby mode (or USB suspend mode). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

3.1.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.1.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.1.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

3.2 ‘Snapshot’ mode (in High or Low resolution) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

3.2.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.2.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.2.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

3.3 ‘Continuous Capture’ mode (in High or Low resolution). . . . . . . . . . . . . . . . . . . . . . . .1 5

3.3.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.3.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.3.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

3.4 Self-timer Mode (in High or Low resolution) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 5

3.4.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

3.5 ‘Clear camera’. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

3.5.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.5.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

CDSTV0680F-C

This version: ST VIBU internal use only

2

CDSTV0680F-CTOC.fm

Commercial in confidence

PRELIMINARY

Digital Camera Chipset; Customer Datasheet, Rev 3.0,

March 2000

STV0680A + VV6444/6410/6500

3.5.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

3.6 ‘Change resolution’. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.6.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.6.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.6.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

3.7 Tethered USB Video mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

3.7.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.7.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.7.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

3.8 Powering the camera off. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.8.1 Entering this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.8.2 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.8.3 Exiting this mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

4. STV0680A hardware interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.1 STV0680A pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.2 Sensor interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.3 Memory interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.3.1 SDRAM Current consumption. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.3.2 SDRAM interface timing requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.3.3 SDRAM refresh Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.3.4 SDRAM initialisation Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 0

4.4 USB interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

4.5 UART module for RS232 interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

4.5.1 RS232 Physical interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

4.5.2 UART Module Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.6 Power management and battery type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

4.6.1 Power switching to USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

4.6.2 Switched sensor supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.6.3 Battery type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.7 Quartz Crystal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

4.8 Numeric LCD interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

4.8.1 LCD types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

4.8.2 LCD interface pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.9 Switches and LED’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.9.1 MODE push button and SHUTTER push button: GPIO0 and GPIO1 . . . . . . . . . . . .21

4.9.2 Input to select between 50 and 60Hz flicker frequency: GPIO3 . . . . . . . . . . . . . . . .21

4.9.3 LED indicator output: GPIO5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

4.9.4 Unused pins: GPIO2, 4, 6, 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

5. PC software. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.1 Driver support available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5.2 Demonstration software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5.3 OEM software. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.4 Software Development Kit (SDK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

5.4.2 API Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

6. Customisation options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

7. Detailed chipset specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

7.1 Typical camera specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

CDSTV0680F-C

This version: ST VIBU internal use only

3

CDSTV0680F-CTOC.fm

Commercial in confidence

PRELIMINARY

Digital Camera Chipset; Customer Datasheet, Rev 3.0,

March 2000

STV0680A + VV6444/6410/6500

7.2 STV0680/STV0680A companion processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

7.3 VV6444 Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

7.4 VV6410 and VV6500 sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.5 Typical current consumption of complete camera . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

7.5.1 Using VV6444 (sensor operates at @ 5V DC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.5.2 Using VV6410/6500 (sensor operates at @ 3.3V DC) . . . . . . . . . . . . . . . . . . . . . . . 33

8. STV0680A Pin descriptions and Package Information . . . . . . . . . . . . . . . . . . . . . . . 34

8.1 STV0680A Pin Listing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.2 STV0680A pinout diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

8.3 STV0680A Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

9. Schematics and example parts list for complete camera design . . . . . . . . . . . . . .40

9.1 Schematics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

9.2 Example Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

10. VV6444 Sensor Pinout and Package Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . 44

10.1 VV6444 Pin Listing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

10.2 VV6444 Pinout Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

10.3 VV6444 Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48

11. VV6410 Pinout information and package dimensions . . . . . . . . . . . . . . . . . . . . . . 50

11.1 VV6410 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 0

11.2 VV6410 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

11.3 VV6410 package Details (36pin CLCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

12. VV6500 Pinout and pin descriptions (48pin LCC package) . . . . . . . . . . . . . . . . . . 54

12.1 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

12.2 VV6500 pin descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

12.3 VV6500 package Details (48 pin LCC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

13. Evaluation kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

14. Ordering details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

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Revision notes

The following changes have been included since revision 2.00.

• Removed all schematics and only show example parts list, instead referring to respective reference designs (in Section 9.)

• Documentation now refers to STV0680A which supercedes STV0680 - see Section 1.2 for explanation.

• Clarified which STV068 0/680A variants and w hich PC operating sy stems offer VfW support a nd RS232 support, offeri ng VfW
support - see Table 3.

• Updated STV0680A pin descriptions (pinout not changed) in Section 8.

• Confirmed user interface functionality in Section 3. and added Table 6 to show modes of operation and button functions.

• Section 3.: Images ca ptured in both ‘Hi gh’ and ‘Low’ resol ution can be st ored in camera memory at the same time. The refore
there is no need for images stored in memory to be cleared before changing image resolution.

• Changed IR filter recommendation, see section Section 2.1.1.

• Added approximate shutter speeds, in

• Adjusted sensor image array sizes in Section 7. to the correct sizes.

• Updated ordering infor mation in Section 14.

• Updated current consumption information of STV0680, STV0680A, VV6444, and complete camera, see Section 7.2 and
Section 7.5.

Table 10

.

• Added VfW framerates for STV0680A (Section 2.1).

• New order number STV0680A-002

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STV0680A + VV6444/6410/6500 Digital Camera Chipset; Customer Datasheet, Rev 3.0,

March 2000

1. Introduction

1.1 Digital camera chipset

This document describes the features and functionality of a CMOS chipset, comprising an STMicroelectronics (ST) CIF or VGA
resolution sensor and an STV0680A companion processor (formerly known as DCA1: Digital Camera ASIC 1), 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.

In stills mode, the camera stores r aw im ag e d ata in memory. The c am era carries out no colour proc es sing, ensuring its s im pli ci ty
and low cost. Subsequent download of raw data to a PC for processing is done through an RS232 (not STV0680-001) or USB
interface, through demo software, a TWAIN driver, or OEM custom application. The license to use the colour algorithm
(embedded in the PC driver software) is included in the price of the chipset.

A video option is pr ovide d, when te ther ed throu gh US B, which c an al low fo r Video f or Wind ows appl icati ons, a nd ‘vi deo cl ips’ c a n
be recorded while untethered by continuously capturing images while in ‘Continuous’ mode, then downloaded to the PC for
playback, using software to create an AVI file.

Precise design guidelines are available from ST as a reference design (see Section 9.) A PC software development kit (SDK) is
available from ST, to interface to the camera and provide the basis for developing a custom software application for stills and/or
video, which includes colour processing software.

Push buttons:

Shutte r

Mode

Optional

LED Indicator

Optional

2 x 7 seg. LC D

Low cost lens

16MBit or 64MB it

SDRAM

Transceiver

Circuit

Power

ement

Mana

Circuit

RS232 interface
to PC

USB interface
to P C

6-9V Battery e.g., PP 3 ,

4-6 x AA, AAA, etc

CMOS Sensor:

VV6444/6410

CIF

VV6500

VGA

LCD

GPIO

Driver

memor

I/F

Sensor data

Sensor clock
Optional

Piezo

Buzzer

Mini

speaker

Switched sensor supply (5V for VV6444, 3v3 fo r VV6410/6500

Buffer Amp

Sensor

I/F

PWM

Audio I/F

12MH z XTAL

STV0680A

RS232

I/F

USB

I/F

Detect Low

Batter

3v3 supply (STV0680A

Figure 1 : Typical camera system block diagram

1.2 Co-processor choices

The following co-processor choices are available. The STV0680A supercedes STV0680, and uses different silicon and different
firmware compared to STV0680. Functionally it is exactly the same as STV0680 except that it supports a VfW driver. In addition,
a new firmware variant means that the STV0680A also supports VV6410 and VV6500 sensors, as well as 64Mbit memory size.

The firmware variant of STV0680 denoted by STV0680-001 does not support RS232 interface.:

Co-

processor

Sensors

supported

SDRAM

supported

USB

interface

RS232

interface

Video for
Windows

support

This version: ST VIBU internal use only

STV0680-001 VV6444 16Mbit onl

Yes No No

STV0680A-002 VV6444/6410/6500 16Mbit or 64Mbit Yes Yes Yes

Table 1 : Product choices

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1.3 Sensor choices

The following sensors are supported:

Sensor Resolution

Sensor supply

VV6444 CIF (352 x 288
VV6410 3.3v
VV6500 VGA

640 x 480

Table 2 : Sensor choices with STV0680/STV0680A

1.4 Key system features

The key features of a typical camera based on the STV0680A chipset are as follows:

1.4.1 Image features (

• Support for 5V or 3.3V CIF resolution sensor (VV6444 or VV6410) - 352 x 288 pixels

• Support for 3.3V VGA resolution sensor (VV6500) - 640 x 480 pixels

• 80 picture storage capacity possible for CIF, with 64MB memory

STV0680A-002

STV0680A + VV6444/6410/6500

voltage

5v

• 26 picture storage capacity for VGA, with 64MBit memory

• A greater numbe r of images can be stored when ‘Low’ resolution mode is enabl ed (e.g. 80 QCIF images with 16M bit memory,
106 QVGA images with 64Mbit memory). See Table 4 and Table 5.

• Automatic anti-flicker exposure and gain control

1.4.2 Image features (

• Supports 5V CIF resolution sensor (VV6444) - 352 x 288 pixels.

• 20 picture storage capacity possible for CIF with 16MB memory.

• 80 picture storage capacity possible for QCIF with 16MB memory.

• Automatic anti-flicker exposure and gain control

STV0680-001

)

1.4.3 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 ‘Conti nuo us’ mode a llo ws captu re of ima ge sequ ences for storag e in memory and sub seque nt dow nload to PC.

• Piezo buzzer indicates a number of useful events to the user, e.g. whether enough light is present for picture capture, etc.

• Indicator LED.

This version: ST VIBU internal use only

1.4.4 User features on PC software

PC software allows a number of features, including fast download of thumbnail images for picture selection, and automatic
detection and correction of sensor defects. Table 3 clarifies the driver compatibility available, including:

• TWAIN driver to suit all TWAIN compatible imaging applications

• Video for Windows d river for tet hered video m ode (throug h USB), a va ilab le at all res olutions , with f as test fram erates at QCIF
resolution

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• AVI video file creation from image sequences captured in ‘continuous’ mode

Interface type:

PC Operating system:

STV680-001 Not available TWAIN

STV0680A-002 TWAIN TWAIN, VfW

Custom OEM softwa re can be de velop ed by usin g t he SDK (fo r SDK a vaila bility , con tact S T), t o uplo ad thu mbnai ls/st ill im ages or
‘continuous’ images, e.g. for AVI file creation.

Win9x, WinNT4, Win2k

RS232

Table 3 : Driver choices

USB

Win98 and Win2k only

March 2000

1.4.5 Power management features and USB compliance

• Picture retention with extremely low power operation, which appears to the user as if the camera is “switched off”.

• Auto power-off after 30sec with no user activity

• Operates from 6-9V battery, although system voltage is 5V or 3.3V, dependant on sensor.

• Low battery detection

• Dependant on ha rdware configura tion, switc h-over to USB powe r supply is su pported, to all ow the devic e to operate wi th low
batteries or without batteries, when connected to USB.

• Full USB compl iance re quirement s are lis ted in the USB spe cification, however , in a ca mera d esigned u sing this c hipset, the
following must at least be inclu ded: (a) an SDRAM with sufficiently low self-r efresh current, (b) USB inrush protectio n circuitry,
and (c) (in the case of VV6444 only) a switched 5V sensor supply is used, to maintain sufficient supply voltage to the 5V
sensor. See Section 9. for further details.

1.4.6 General features

• High speed picture download over USB

• ST Colour processing algorithms available under license (as part of drivers/SDK)

• USB or RS232 serial interface options, and VfW / TWAIN driver support.

• Customisation of STV0680A is possible to vary the features described in this document, subject to commercial agreement
with ST, see Section 6.

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2. Detailed features

2.1 Sensor type and image formats

The sensor type is auto-detected by STV0680A, which ensures that the correct sensor timing is enabled, and the correct image
resolutions are enabled, as shown in Table 4.

For stills photo grap hy , ‘ High’ or ‘Low’ reso lu tion m od e can be selected, t o give CIF or QCIF pi ct ures from a CIF sens or, an d VGA
or QVGA from a VGA sensor (see Table 4 and Section 3.7). 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 for
images stored in memory to be cleared before changing image resolution.

Where USB is connected, the host PC software (through a Video for 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..

Sensor

VV6444/

6410

Max. no. of

Sensor

Image Size

Resolution

mode

Final Image Size

images

stored in

16MBit

memory

CIF 352 x 288 High CIF 352 x 288 20 80 9 frames/sec

Low QCIF 176 x 144

(Subsampled)

80 320

Max. no. of

images

stored in

64MBit

memory

(see notes)

Approximate

VfW framerate

(*)

25 frames/sec

VV6500 VGA 640 x 480 High VGA 640 x 480 (6) 26 2 frames/sec

Low QVGA 320 x 240

(Subsampled)

Table 4 : Image modes supported (

*Notes:

1. VfW framerate is dependant on PC performance and USB bus loading

2. Not all image sizes are supported by all STV0680/680A variants - see Table 2 for clarification.

3. A CIF camera with STV0 680A-002 and 64Mbit SDRAM can stor e up to 320 im ages b y using QC IF mode. Whe re >99 im ages
are still available, the LCD display will remain at 99. Where (no. of images available) <99, the LCD display will show the
number of images available, as is the case with all other modes.

(24) 106 12 frames/sec

STV0680A-002

)

Max. no. of

Sensor

Sensor

Image

Size

Resolution

mode

Final Image Size

images

stored in

16MBit

memory

VV6444 CIF 352 x

288

High CIF 352 x 288 20

Low QCIF 176 x 144

(Subsampled)

80

This version: ST VIBU internal use only

Table 5 : Image modes supported (

STV0680-001

)

2.1.1 VV6444

VV6444 is a CIF resolution, 5V CMOS imaging sensor. A brief specification is shown in Section 7. VV6444 has the same
functionality and array size as the un-microlensed VV6404 sensor, but has a microlensed array and different colour
characteristics. Although the VV64444 and VV6404 are electrically identical, the STV0680 and STV0680A use the correct

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settings for the VV6444 colour set. This means that a VV6404 should not be used with STV0680/680A.
For IR filter design, the best choice filter follows the GS0034 dielectric stack filter specification, which is available from ST. An

alternative, although not optimal filter, would be Schott S8612 doped glass, also sold as CM500.

March 2000

2.1.2 VV6410

VV6410 is a CIF resolution, 3.3V CMOS imaging sensor. A brief specification is shown in Section 7.
A dual design to support VV6444 and VV6410 is not possible, since VV6410 is a 3v3 sensor. A dual footprint for VV6410 and

VV6500 is not possible since the package types differ, however, the same support circuit is used. See Section 9.

2.1.3 VV6500

VV6500 is a VGA resolution, 3.3V CMOS imaging sensor. A brief specification is shown in Section 7.
A dual design to support VV6444 and VV6500 is not possible, since VV6500 is a 3v3 sensor. A dual footprint for VV6410 and

VV6500 is not possible since the package types differ, however, the same support circuit is used. See Section 9.

2.2 User interface

The user interface supported by STV0680A comprises of user controls, audible signals and visual displays.

! Note

The precise functionality of the
version shown here is close to the actual functionality available in STV0680A.

user interface

may vary from that of existing demonstration units. The

2.2.1 Push buttons

The following are typical of the type of funct ions whic h are supported by the chipset. Th ese functio ns are achie vable wit h no more
than 2 push buttons.

1. Mode button (Wake-up/Switch between modes)
when the camera is to be used for taking pictures, or (1.2) to switch between modes of operation shown in Section 3..

2. Shutter button (Shutter/confirm action): This button allows the user to take a picture or confirm an action, as shown in Sec­tion 3.

The modes of operation are described in Section 3.

: This button al lows th e user (1.1) t o wa ke the c amera u p from sta ndby mode

2.2.2 LED indicator

An LED display camera status, i.e. to show that the camera is in ‘Snapshot’ mode.

2.2.3 Picture counter using 2 x 7 segment display

STV0680A stores a picture counter value, which shows how many images can still be captured. STV0680A supports a 2x7
segment LCD panel. In ‘Snapshot’ mode and continuous capture mode, this LCD panel displays the number of pictures still
available, which is useful to identify when the user is approaching the maximum number of images which can be stored (see
Table 4 and Table 5). It is possible to clear the images stored in memory, in order to continue taking pictures, as shown in Table

6. In other modes, this LCD panel shows displays a 2-character code as shown in Table 6, which helps the user to navigate
around the modes.

Note

: A CIF camera with STV0680A-002 and 64Mbit SDRAM can store up to 320 images by using QCIF mode. Where >99
images are still available, the LCD display will remain at 99. Where (no. of images available) <99, the LCD display will show the
number of images available, as is the case with all other modes.

This version: ST VIBU internal use only

For suitable numeric LCD panel types, see Section 4.8.

2.2.4 Piezo buzzer

An on-chip Pulse Width Modulator (PWM) on STV0680A is used to generate buzzer sounds to signal certain events. The
following are typical of the type of events which are indicated by the buzzer, and each has its own distinctive sound:

1. Camera has been ‘Woken up’ from standby mode (either b y th e us er pres s ing a b u tton , by re-connecting the power source,
or by connecting a USB/RS232 connection).

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2. Camera has been ‘gone to sleep’ i.e. moved into standby mode. Pictures are retained in memory.

3. Picture has been successfully taken after the user presses the capture button.

4. Picture has NOT been taken after the user presses the capture button. This indicates to the user that there is insufficient
light, or that the exposure control was not ready due to a rapid change of lighting in the scene.

5. Picture has NOT been taken after the use r p r ess es th e c apture button, due to picture counter having reached the m axi mum
number of images. The user has the chance to zero the counter if desired.

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

7. Self-timer activated and counting down.

March 2000

STV0680A + VV6444/6410/6500

2.3 Battery Level Detect and USB auto-switch

An on-chip battery level detector on STV0680A detects when the battery voltage falls below a threshold. This threshold is
determined by the designer, dependant on the perception of what remains as ‘acceptable’ image quality as the battery voltage
falls. The chos en th res hol d level is determi ne d by a resistor va lu e, as s how n i n Se ction 9. Where no USB has been de tec ted, the
LCD display flashes, which indicates that the battery is low. Where a USB connection has been detected, the camera sources
power from USB, if certain additional hardware is fitted.

Note

: It may be a requirement of certain USB compl iance tests tha t such additi onal ha rdware is in cluded 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 PC interface options and software support

Either USB Interface (full speed 12Mbit/sec max.) or RS232 interface (115.2Kbaud) is supported by the chipset, with driver
software available from ST for both. The interface type is auto-detected by the chipset. PC software can be one of the following
(exact compatibility is clarified in Table 3):

1. Simple image upload demonstration software supplied by ST, allowing uploading of stills or ‘continuous’ images. This soft­ware should not be supplied as an end-user product.

2. TWAIN driver to suit all TWAIN compatible imaging applications

3. Video for Windows driver for tethered video mode (USB only)

4. Custom end-user soft ware developed by O EM u sin g SD K (for SDK a vailability, contact ST). The SDK is sup pl ied by ST as a
32-bit DLL f ormat, running on Windo w s 98, a nd ac cess ed throu gh a do cume nted s oftw are i nterface. This pro vide s the b asis
for developing a custom software application for uploading stills and/or video. See Section 5. for further details.

2.4.1 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 seconds per image for a CIF image (0.6 seconds for a VGA image),
plus post processing time per image.

For USB interface details, see Section 4.4.
Note

: Actual USB download and post processing time also depends on PC performance and USB bus loading

2.4.2 RS232 (not available on STV0680-001)

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 i s selec ted for down load, full im age d ownloa d take s a pproxi matel y 10 s econ ds pe r imag e for a CIF ima ge (arou nd
30 seconds for a VGA image), plus post processing time per image (of the order of 1 second approximately).

This version: ST VIBU internal use only

For RS232 interface details, see Section 4.5.
Note

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

2.5 Anti-flicker exposure and gain control

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 minimise ‘flicker’ effects. Detection of

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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 ‘Snapsh ot’ mode, th e ch ipset capt ures an im age if th e expos ure and gain val ue has re ached a suitab le valu e for th e
current scene. If the light detected 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.

Note

: Auto-detect of the mains lighting frequency is not currently supported.

March 2000

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3. Camera modes of operation

Mode

Standby

mode

’Snapshot’

mode

Continu-

ous cap-

ture

Self timer Takes one pi cture after a 10 second co unt-

’Clear

camera’

If shutter button pressed while in

this mode

No function - pictures cannot be taken in

standby mode

Takes one picture, if sufficient light availa-

ble, then returns to ‘Snapshot’ mode

Takes a picture every 80mS while button

pressed, regardless of light available, then

returns to ‘Snapshot’ mode

down, if sufficient light available, then

returns to ‘Snapshot’ mode

(1st press:)

Prompts user to

clear camera

2nd press:) Clears all

ima

es stored in cam­, then returns to

era

‘Snapshot’ mode

pressed while in this

Moves to continuous cap-

Moves to self timer mode Returns to

Moves to ‘Clear camera’

Moves to ‘Change resolu-

March 2000

If mode button

mode

Wakes up camera into

‘Snapshot’ mode

ture mode

mode

tion’ mode (see note)

STV0680A + VV6444/6410/6500

If no further

action

Remains in

standby mode

Stays in ‘Sna p-

shot’ mode for

30 seconds then

moves to

standby mode

‘Snapshot’ mode

after 5 seco nds

LCD

displays

(Display is

blank)

Number of pic­tures still avail-

able to take

Number of pic­tures still avail-

able to take

“St”

“CL”

’Change

resolution’

Changes resolution

High to Low) and return s to ‘Snapshot’

(i.e. Low to High, or

mode

Returns to ‘Snapshot’

mode

If currently in

Low Resolu-

tion: “Hr”

If currently in

High resolu-

tion: “Lr”

Table 6 : Camera modes

Note: In STV0680-001, pressing the Mode button while in ‘Clear Camera’ mode only moves onto ‘Change resolution’ mode if the
camera has no images stored. This is because in STV0680-001, mixed resolutions (i.e. ‘High’ and ‘Low’) cannot be stored at the
same time. In STV0680A-002, mixed resolutions can be stored at the same time.

The above modes are interrupted by the detection of a USB or RS232 connection. This is to allow for the possibility that the PC
driver takes control of the chipset (e.g. when starting a VfW application through USB).

3.1 Standby mode (or USB suspend mode)

3.1.1 Entering this mode

The camera enters st and by mo de aut omati cally af ter 3 0 secon ds of inacti vity if not tethere d to USB, or w hen USB suspe nd mode
is activated by the PC driver.

3.1.2 Description

This allows image data to be stored in memory with extremely low power consumption, which appears to the user as if the
camera is switched ‘off’, since there is no LCD display or LED lit. In VV6444-based designs, STV0680A powers off the sensor
completely, in VV6410/6500 based designs, the sensor is placed in suspend mode, and the camera enters a mode where only
SDRAM refresh is carried out. The shutter button is inactive in standby mode.

This version: ST VIBU internal use only

3.1.3 Exiting this mode

Wake-up from standby mode is achieved by any of the following means:

1. Pressing the ‘mode’ button (only if no USB detected)

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2.

RS232 receives start bit from host software

3. USB connection detected

4. If in USB suspend mode, U SB driver re-starts communications with the camera as per USB specification

(only if no USB detected

March 2000

3.2 ‘Snapshot’ mode (in High or Low resolution)

3.2.1 Entering this mode

This is the default mode on wake-up when not tethered to the PC, i.e. pressing the Mode button while in standby mode, or
powering up the camera. On entering this mode, the current resolution (i.e. ‘Hr’ or ‘Lr’) is displayed briefly, and there is a brief
pause (approx. 1second) during which pictures cannot be taken. This is to allow the Auto-exposure and Gain control to settle.
The LCD then displays the number of pictures still available.

3.2.2 Description

Using the shutter button, ‘Snapshot’ mode allows single pictures to be grabbed using the capture button. The LCD displays the
number of pictures still available. Auto-exposure and gain are continuously enabled. The camera grabs an image when the
capture button is pressed, if sufficient light is available, the exposure and gain algorithm is settled, and picture counter has not

reached it s

maximum. Image data is stored in memory and picture counter is decremented.

3.2.3 Exiting this mode

After 30 seconds of non-activity, while not tethered to the PC, the camera goes into Standby mode.

3.3 ‘Continuous Capture’ mode (in High or Low resolution)

3.3.1 Entering this mode

Enabled using the mode button (from ‘Snapshot’ mode, press once).

3.3.2 Description

The LCD displays “Ct”. Auto-exposure and gain are continuously enabled. While the shutter button is pressed, the user can
activate continuous capture at approx. 12.5 frames per second, to allow recording of a ‘video’ sequence, whether or not the
camera is tethered to the PC, and regardless of whether enough light is available. The picture counter is decremented once per
frame. The continuous image data is stor ed in memor y and can then be downloa ded to the PC. Once the memory is fu ll, the user
is alerted by an audible tone. It is possible to store a mixture of still images and ‘Continuous’ images in memory.

3.3.3 Exiting this mode

After 5 seconds of non-activity, or after releasing the shutter button, the camera returns to standby mode.

3.4 Self-timer Mode (in High or Low resolution)

3.4.1 Entering this mode

Enabled using the mode button (fro m ‘Snapshot’ mode, press twice).

3.4.2 Descript ion

The LCD displays “St”. Auto -exposure and gain are co ntinuous ly enable d. When the shut ter button is pressed, t he camera cou nts
down 10 seconds, then grabs an image, if sufficient light available and exposure and gain algorithm settled, and picture counter

has not reached its

maximum. Image data is stored in memory and picture counter is decremented.

This version: ST VIBU internal use only

3.4.3 Exiting this mode

After 5 seconds of non-activity, or after the timer has counted down 10 seconds, the camera returns to standby mode.

3.5 ‘Clear camera’

3.5.1 Entering this mode

Enabled using the mode button (from ‘Snapshot’ mode, press three times).

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3.5.2 Description

The LCD displays “CL”. Pressing shutter button twice will clear all the images in the camera.

3.5.3 Exiting this mode

After 5 seconds of non-activity, or after the camera has been cleared, the camera returns to standby mode.

3.6 ‘Change resolution’

3.6.1 Entering this mode

This is enabled using the mode button (from ‘Snapshot’ mode, press four times).
Note: In STV0680-001, the images stored in memory must be cleared before this mode can be entered. This is because in

STV0680-001, mixed resolutions (i.e. ‘High’ and ‘Low’) cannot be stored at the same time.

3.6.2 Description

The LCD displays the target resolution to which the camera can be changed, i.e. if in High resolution “Lr” (Low resolution) is
displayed, if in Low resolution, “Hr” (High resolution) is displayed. ‘High’ resolution stores the full image resolution from the sensor
array, while ‘Low’ subsamples the sensor array, to store 4x the number of images (e.g. 80 in QCIF mode, compared to 20 in CIF
mode).

Dependant on the type of s en sor us ed, diff eren t res ol uti ons are obt ained, see Table 4 or Tab le 5 . By pres s ing the sh utte r but ton,
user changes the resolution.

3.6.3 Exiting this mode

After 5 seconds of non-activity, or after the resolution has been changed, the camera returns to standby mode.

3.7 Tethered USB Video mode

3.7.1 Entering this mode

This is activated by the PC Video for Win dows driv er w hi le the cam era is tethered, dependant on whethe r VfW is supp orte d (se e
Table 3).

3.7.2 Descript ion

The camera is controlled by the PC driver.
Note: Any images or continuous image sequences contained in the camera are lost when the video for Windows driver starts.

3.7.3 Exiting this mode

This is controlled by the PC drivers.

3.8 Powering the camera off

3.8.1 Entering this mode

This is not truly a mode of operation, but a description of what happens if:

• The battery power and USB connection are removed from the camera

• The battery power is removed, and the PC to which the camera is tethered, is switched off.

This version: ST VIBU internal use only

• The battery v olt age falls extremely low. Ways of a vo idi ng this situation a re discussed in th e reference design, see Section 9 .

Note: normally a camera with U SB in terfa ce sho ul d so urc e po wer fro m th e USB connection, but this is hard ware dep end ant, see
Section 9.

3.8.2 Description

In this situation, all image data is lost.
Note: under certain circumstances, the image data may be maintained if the camera or PC is powered on again after a few

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3.8.3 Exiting this mode

When the camera is pow ered on again, ei ther when the battery is re-f itted, or t he USB is re-connec ted, or the PC is re-started, the
camera will power up into standby mode, High resolution, with all images available.

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4. STV0680A hardware interfaces

4.1 STV0680A pinout

The STV0680A pinout has been carefully developed to minimise the physical size of the support printed circuit board by
facilitating placement of and electrical routing to peripheral support components such as the SDRAM. The complete pinout and
listing is shown in Section 8.

4.2 Sensor interface

STV0680A uses a standard ST digital interface from the sensor, and the sensor clock input is provided by an output from
STV0680A. Designing a camera using this chipset should design as close as possible to the reference design (Section 9.), in
which case the chipset can be regarded as a functional ‘bla ck box’, and no further details regar ding the STV0680A-sensor
interface are required.

4.3 Memory interface

STV0680A is designed to in terfa ce to an ex te rnal 16 Mb it or 64Mbit SDRAM (see Ta ble 4 and Table 5). The SDRAM device mu st
have a 16 bit wide data bus and op erate from a 3.3V sup ply. Two si zes of SD RAM memory are suppor ted by STV068 0A, 16MBits
(1M x 16 bits wide) or 64MBits (4M x 16 bits wide), the memory size is auto-detected by STV0680A. STV0680A clocks the
SDRAM at 6MHz, typica lly thi s i s well below the figures offered by most manufactu rers ’ de vic es . D ev ic es whic h are PC 66 a nd/o r
PC100 compliant are preferred. For interface wiring, see Section 9.

4.3.1 SDRAM Current consumption

For maximum system battery li fe while no picture s are bein g taken, an d to assi st in mee ting require ments for U SB compl iance, an
SDRAM should be chosen with the lowest possible self refresh current specification. For suggested SDRAM part numbers, see
Section 9.

4.3.2 SDRAM interface timing requirements

The following timing diagrams should be referred to when selecting SDRAM other than those recommended in Section 9.

DCLK

CKE

Command

A0-9,BA

A10

DQM

DQ

t

CK

t

t

CMS

CMH

ACTIVE

ROW COLUMN

ROW

t

AS

t

t

AH

RCD

t

CMS

t

L

READ

t

H

READ Latenc

t

AC

DOUT M

t

RAS

NOP PRECHARGE NOP

t

CMH

t

OH

DOUT M + 1 DOUT M + 2 DOUT M + 3

t

RC

t

RP

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