2.1 Address Mode

This mode is only set the first time the USI Overflow Interrupt is executed after the START condition is detected. The data has already been sampled into the USI data register. If the address is not recognized the interface is reinitialized to wait for the next START condition, and therefore discards the rest of the message.

If it is a “general call” a bit in the status register will be set. Any actions that need to be taken based on this must be carried out by the main application.

The direction mode is read from the eight bits in the address transmission, and is stored in the masterReadDataMode status bit, before the byte is acknowledged by the slave.

Depending on the masterReadDataMode setting, a transmission/reception is prepared before leaving the interrupt and waiting for the sampling of the next eight bits.