Case M2: Address Packet Transmit Complete - Address not Acknowledged by Slave

If no slave device responds to the address, the Master Write Interrupt Flag (WIF in TWI.MSTATUS) and the Master Received Acknowledge Flag (RXACK in TWI.MSTATUS) are set. The RXACK flag reflects the physical state of the ACK bit, i.e. no slave did pull the ACK bit low. The clock hold is active at this point, preventing further activity on the bus.