29.3.3.3 Smart Mode

The TWI interface has a Smart mode that simplifies the application code and minimizes the user interaction needed to adhere to the I²C protocol.

For the TWI host, the Smart mode will automatically send the ACK action as soon as the Host Data (TWIn.MDATA) register is read. This feature is only active when the Acknowledge Action (ACKACT) bit in the Host Control B (TWIn.MCTRLB) register is set to ACK. The TWI host will not generate a NACK after the MDATA register is read if the ACKACT bit is set to NACK. This feature is enabled when the Smart Mode Enable (SMEN) bit in the Host Control A (TWIn.MCTRLA) register is set to ‘1’.

For the TWI client, the Smart mode will automatically send the ACK action as soon as the Client Data (TWIn.SDATA) register is read. The Smart mode will automatically set the Data Interrupt Flag (DIF) to ‘0’ in the Client Status (TWIn.SSTATUS) register if the TWIn.SDATA register is read or written. This feature is enabled when the Smart Mode Enable (SMEN) bit in the Client Control A (TWIn.SCTRLA) register is set to ‘1’.