VV5404 datasheet(35/54 Pages) STMICROELECTRONICS

35 / 54 page

VV5404 & VV6404

CD5404-6404F-A

35/54

5.5.9

Exposure Control Registers [010_00002] - [010_10012]

There is a set of programmable registers which controls the sensitivity of the sensor. The registers are as follows:

1. Fine exposure.

2. Coarse exposure time.

3. Gain.

4. Clock division.

The gain parameter does not affect the integration period rather it amplifies the video signal at the output stage of the

sensor core.

Note: The external exposure (coarse, fine, clock division or gain) values do not take effect immediately. Data from

the serial interface is read by the exposure algorithm at the start of a video frame. If the user reads an exposure value

via the serial interface then the value reported will be the data as yet unconsumed by the exposure algorithm, because

the serial interface logic locally stores all the data written to the sensor.

Between writing the exposure data and the point at which the data is consumed by the exposure logic, bit 0 of the

status register is set. The gain value is updated a frame later than the coarse, fine and clock division parameters,

since the gain is applied directly at the video output stage and does not require the long set up time of the coarse and

fine exposure and the clock division.

To eliminate the possibility of the sensor array seeing only part of the new exposure and gain setting, if the serial

interface communications extends over a frame boundary, the internal re-timing of exposure and gain data is disabled

while writing data to any location in the Exposure page of the serial interface register map. Thus if the 5 bytes of

exposure and gain data is sent as an auto-increment sequence, it is not possible for the sensor to consume only part

of the new exposure and gain data.

The range of some parameter values is limited and any value programmed out-with this range will be clipped to the

maximum allowed.

oeb_composite

su5[4]

su5[3]

Comments

Drive strength = 2mA

Default drive strength = 4mA

Drive strength = 6mA

unallocated

Outputs are not being driven therefore

driver strength is irrelevant

Table 23 : Output driver strength selection

VV5404 датащи(PDF) 35 Page - STMicroelectronics