Case M4: Address Packet Transmit Complete - Direction Bit Set

If the master receives an ACK from the slave, the master proceeds to receive the next byte of data from the slave. When the first data byte is received, the Master Read Interrupt Flag (RIF in TWI.MSTATUS) is set and the Master Received Acknowledge Flag (RXACK in TWI.MSTATUS) is cleared. The clock hold is active at this point, preventing further activity on the bus.