4.7 Acknowledge (ACK/NAK)

Each receiving device, when addressed, must generate an ACK bit after the reception of each byte. The master device must generate an extra clock pulse for ACK to be recognized.

The Acknowledging device pulls down the SDA line for t_SU-DATA before the low-to-high transition of SCL from the master. SDA also needs to remain pulled down for t_H-DATA after a high-to-low transition of SCL.

During read, the master must signal an End-of-Data (EOD) to the slave, by not generating an ACK bit (NAK), once the last bit has been clocked out of the slave. In this case, the slave will leave the data line released to enable the master to generate the Stop condition.