Operation

VT5366

16/30

5.3

Initialization

It is recommended that the VT5366 autoclear function is activated during a read. To do this

the processor should write the value 0x02 to register 0x20 after enabling the VT5366 (by

setting PowerDown LOW). This only needs to be done once after the power supply has

been applied.

5.4

Reading the X any Y motion vectors

It is recommended that the processor reads the motion data at a rate of around every 2ms.

The X and Y motion information is read using a single I2C ‘multiple read’ transaction. The

sequence is as follows;

(1) Read I2C registers 0x21 (contains X-motion) and 0x22 (contains Y-motion).

Note that these two registers MUST be read with a single I2C ‘multiple read’ transaction.

See

Chapter 6.

As shown above X and Y motion vectors can be read from registers 0x21 and 0x22. The

values are in 2’s complement notation to allow positive and negative motion to be

represented. The values read represent the accumulated motion since the last time the

registers were read. As soon as the registers have been read they will automatically be reset

to 0 and the Motion Detect output (pin 24) will go LOW.