SLVSE65C July 2018 – December 2023 DRV8847
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
To read from a slave device, the master device must first communicate to the slave device which register will be read from. This communication is done by the master 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 master device then sends the register address of the register to be read from. When the slave device acknowledges this register address, the master device sends a START condition again, followed by the slave address with the R/W bit set to 1b (signifying a read). After this process, the slave device acknowledges the read request and the master device releases the SDA bus, but continues supplying the clock to the slave device.
During this part of the transaction, the master device becomes the master-receiver, and the slave device becomes the slave-transmitter. The master device continues sending out the clock pulses, but releases the SDA line so that the slave device can transmit data. At the end of the byte, the master device send a negative-acknowledge (NACK) signal, signaling to the slave device to stop communications and release the bus. The master device then sends a STOP condition.