27.3.2.3 TWI Client Operation

The TWI client is byte-oriented with optional interrupts after each byte. There are separate interrupt flags for the client data and address/Stop recognition. Interrupt flags can also be used for polled operations. Dedicated status flags indicate ACK/NACK received, clock hold, collision, bus error, and R/W direction.

When an interrupt flag is set to ‘1’, the SCL is forced low, giving the client time to respond or handle any data, and will, in most cases, require software interaction. The number of interrupts generated is kept to a minimum by automatically handling most conditions.

The Address Recognition Mode (PMEN) bit in the Client Control A (TWIn.SCTRLA) register can be configured to allow the client to respond to all received addresses.