14.2.4.2 Slave Mode
After setting the ENS1 bit in the 14.4.1 Control Register, the I2C peripheral is in Slave mode (which is not addressed by the master). The I2C peripheral checks for its own slave address and the general call address. If one of these addresses is detected, the I2C peripheral is addressed by the master and then an interrupt is requested. The I2C peripheral can operate as a slave transmitter or a slave receiver.