27.3.2.2.3.3 Case M3: Address Packet Transmit Complete - Address not Acknowledged by Client
If no client device responds to the
address packet, the WIF and the RXACK flags will be set to ‘1’. The clock
hold is active at this point, forcing the SCL low.
The missing ACK response can indicate that the I2C client is busy with other tasks or is in a sleep mode and cannot respond.
The software can prepare to take one of the
following actions:
- Retransmit the address packet
- Complete the transaction by issuing a Stop condition in the Command (MCMD) bit field from the Host Control B (TWIn.MCTRLB) register, which is the recommended action