Serial Communication

VV5430

CD5430F-A

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8.

Serial Communication

The VV5430 includes a full duplex (two-wire) serial interface, and can be controlled and configured by a host processor. The base

pins 20 and 16. This allows up to four separate camera devices to be controlled on one serial link, which, for example, makes

multiplexing of camera outputs possible.

The serial interface reads or writes data to a set of Registers that define the characterisation of the sensor, and control certain

operations.

8.1

Serial Communication Protocol

The host must perform the role of a communications master and the camera acts as either a slave receiver or transmitters

communication between host and camera takes the form of three or five byte messages of 8-bit data, with a maximum serial clock

(SCL) frequency of 100kHz. Since the serial clock is generated by the host, the host determines the data transfer rate.

The host processor initiates a message by forcing both Serial Data (SDA) and Serial Clock (SCL) low. The first byte addresses

the required device, and defines either a READ message (four bytes to follow) or a WRITE message (two bytes to follow). After

the camera has acknowledged a valid address (ACK, bit 9 of SCL), the host then either reads four bytes of data from the camera

or transmits a further two bytes to the camera. The data transfer protocol on the bus is illustrated below:

Figure 8 : Data Transfer Protocol

1

2

78

9

1

2

3 - 8

9

Start condition

Stop condition

SDA

SCL

MSB

ACK

ACK

Read/Write bit

Acknowledge from receiver

P

S