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10. Write to Camera

Information to be communicated from host to camera consists of configuration data (for example automatic gain control ON), and

parametric information (for example sensor integration time). The write data is formed into two bytes. A 4-bit Header Code in the

first byte is used by the camera to determine the destination of the 12-bit message following the header.

Figure 10 : Receive Data Format

After the camera acknowledges the receipt of a valid address the host transfers the first data byte which the camera

acknowledges by pulling SDA low. The second byte is then sent followed by a final acknowledge from the camera. A stop

condition is produced by the host after the second message byte. As with the read procedure, the stop condition is not absolutely

necessary as the camera’s serial interface will reset automatically after two bytes have been received.

The valid Header Codes and their data structures are fully described in the following pages.

10.1 Timing Protocol

When an exposure or gain value has been written to the camera it is held in the interface until the camera is ready to consume

the new data. For correct operation, there should be no further read or write accesses to the camera during this hold period.

Normal communication between other modules connected to the serial interface will not cause problems. The minimum length of

the wait period is

S

ADDRESS[7:1]

W

A

DATA[11:8]

DATA[7:0]

AA P

Write = 0

Camera acknowledge (valid address)

Camera acknowledge

HEADER

0 0 1 0 0 x x 0