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

For the TWI Slave, the Smart mode will automatically send the ACK action as soon as the Slave Data (TWIn.SDATA) register is read. The Smart mode will automatically set the Data Interrupt Flag (DIF) to ‘0’ in the Slave 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 Slave Control A (TWIn.SCTRLA) register is set to ‘1’.