STV-DCA/VGA-E01 STMICROELECTRONICS [STMicroelectronics], STV-DCA/VGA-E01 Datasheet - Page 21

• Manufacturer Part Number: STV-DCA/VGA-E01
• Description: Low Cost Digital Camera (LCDC) Chipset
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STV0680A + VV6444/6410/6500
4.6.1
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 (see also Section 9.):
4.6.2
Dependant on the hardware implementation, the SENSPWR output from STV0680A can be used to power off completely the
sensor during Standby mode (in the case of VV6444) or put the sensor into Suspend mode (in the case of VV6410/6500). This
has a significant improvement on battery life.
4.6.3
This is hardware dependant. The schematics referred to in Section 9. assume either three or four 1.5V cells.
4.7
Regardless of the sensor type or anti-flicker requirements, the sensor + STV0680A chipset operates from a single 12MHz
fundamental quartz crystal. For specification requirements, see Table 15. STV0680A includes an on-chip low jitter PLL, for PLL
characteristics, see Table 14.
4.8
STV0680A supports a 2-digit LCD panel only, for alpha-numeric display.
4.8.1
STV0680A 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 .
4.8.2
'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
4.9
The GPIO lines on STV0680A have pre-defined functions as follows, see Section 2.2 for user interface functionality, and Section
9. for precise hardware implementation.
4.9.1
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.
4.9.2
This allows for factory setting of the anti-flicker frequency, dependant on the final country of destination. See also Section 2.5.
The polarity of this selection is detailed in the reference design (see Section 9.).
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STV0680F_contents.fm
! Note
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The USBDETECT input to STV0680A 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
Quartz Crystal
Numeric LCD interface
Switches and LED’s
Power switching to USB
Switched sensor supply
Battery type
LCD types
LCD interface pinout
MODE push button and SHUTTER push button: GPIO0 and GPIO1
Input to select between 50 and 60Hz flicker frequency: GPIO3
The precise functionality of early demonstration units may vary from the actual user interface supported
by STV0680A.
fifteen signals in total.
Digital Camera Chipset; Customer Datasheet, Rev 3.0, March 2000
Commercial in confidence
CDSTV0680F-C
PRELIMINARY