JAJSSE7 November 2023 DRV8214
PRODUCTION DATA
To read from a follower device, the leader device must first communicate to the follower device which register will be read from. This communication is done by the leader starting the transmission similarly to the write process which is by setting the address with the R/W bit equal to 0b (signifying a write). The leader device then sends the register address of the register to be read from. When the follower device acknowledges this register address, the leader device sends a START condition again, followed by the follower address with the R/W bit set to 1b (signifying a read). After this process, the follower device acknowledges the read request and the leader device releases the SDA bus, but continues supplying the clock to the follower device.
During this part of the transaction, the leader device becomes the leader-receiver, and the follower device becomes the follower-transmitter. The leader device continues sending out the clock pulses, but releases the SDA line so that the follower device can transmit data. At the end of the byte, the leader device sends a negative-acknowledge (NACK) signal, signaling to the follower device to stop communications and release the bus. The leader device then sends a STOP condition.