L9961 datasheet(42/65 Pages) STMICROELECTRONICS

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3.10.3

Single read/block read

The READ operation shall be used to retrieve information from the internal I2C registers. However, as the device

implements a clear on write approach, it will not clear any latch.

Figure 13. I2C generic READ operation

GADG220620221333SA

The elementary READ operation consists of:

A START condition

The SLAVE ADDRESS byte (with R/ W = 0) identifying the slave device to be activated

The REGISTER ADDRESS byte identifying the memory address where data has to be read

A STOP condition

This first instruction subset loads the starting address into the memory address counter. Then the following

sequence starts the download of the data:

A START condition

The SLAVE ADDRESS byte (with R/ W = 1) identifying the slave device to be activated

L9961 will output two data bytes

L9961 will output an optional CRC byte covering all the previous bytes

In a block read, MCU can continue reading by clocking additional packets of two data bytes (plus a third CRC

byte optionally generated by L9961). The REGISTER ADDRESS defined at step 3 will be considered as the

starting address, and the memory address counter will be incremented by 1 at every 2 bytes output.

In case REGISTER ADDRESS saturates, L9961 will output 0xFF bytes.

The READ operation terminates with a STOP condition.

3.10.4

Single WRITE/block WRITE

The WRITE operation shall be used for configuring device parameters and sending actuation commands. As the

I2C peripheral implements a clear on write approach, the WRITE operation must also be used to reset any latch

writing a logic ‘1’ to the corresponding bit.

L9961

I2C protocol layer

DS14012 - Rev 3

page 42/65

L9961 датащи(PDF) 42 Page - STMicroelectronics