VS6724 Datasheet, PDF (26/118 Pages) STMicroelectronics – 2 Megapixel single-chip camera module

Functional description
VS6724
Note:
STOP mode: This is a low power mode. The analogue section of the VS6724 is switched off
and all registers are accessed over the I²C interface. A run command received in this state
automatically sets a transition through the Pause state to the run mode.
If a STOP command is issued while streaming an incomplete frame may be generated, it is
recommended that a Pause command is issued and a timeout set in bTimeToPowerdown to
force an automatic transition to STOP.
The analogue video block is powered down, leading to a lower global consumption.
Pause mode: In this mode all VS6724 clocks are running and all registers are accessible
but no data is output from the device. The device is ready to start streaming but is halted.
This mode is used to set up the required output format before outputting any data.
The analogue video block is powered down, leading to a lower global consumption
The PowerManagement register can be adjusted in PAUSE mode but has no effect until the
next RUN to PAUSE transition.
RUN mode: This is the fully operational mode. In running mode the device outputs a
continuous stream of images, according to the set image format parameters and frame rate
control parameters. The image size is derived through downscaling of the UXGA image
from the pixel array.
ViewLive: this feature allows different sizes, formats and reconstruction settings to be
applied to alternate frames of data, while in run mode.
Snapshot mode: The device can be configured to output a single frame according to the
size, format and reconstruction settings in the relevant video pipe context. In normal
operation this frame will be output, once the exposure, white balance and dark-cal systems
are stable. To reduce the latency to output, the user may manually override the stability
flags.
The snapshot mode command can be issued in either Run or Stop mode and the device will
automatically return previous state after the snapshot is taken. The snapshot mode must not
be entered into while ViewLive is selected.
FLASHGUN mode: In flashgun mode, the array is configured for use with an external
flashgun. A flash is triggered and a single frame of data is output and the device
automatically switches to Pause Mode.
VS6724 supports the following flashgun configurations:
● Torch Mode - user can manually switch on/off the FSO IO pin via a register setting.
Independent of mode.
● Pulsed Mode - the flash output is synchronized to the image stream. There are two
options available:
– Pulsed flash with snapshot. Device outputs a single frame synchronized to flash.
– Pulsed flash with viewfinder. Device outputs a flash pulse synchronized to a single
frame in the image stream.
– In the pulsed mode there are two possible pulse configurations:
– Single pulse during the interframe period when all image lines are exposed. This is
suitable for SCR and IGBT flash configurations. The falling edge of the pulse can
be programmed to vary the width of the pulse.
– Single pulse over entire integration period of frame. This is suitable for LED flash
configurations.
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