37.3.12.1.3 ACNTMD = 2 (16 bits are loaded into I2CxCNT)

In Host Transmit mode, the first two bytes following either the 7-bit or 10-bit client address are transferred from I2CxTXB into both high and low bytes of the I2CxCNT register in addition to the transmit shift register.

Important: When using the auto-load feature in any Transmit mode (Client, Host, Multi-Host), the first of the two bytes following the address is the I2CxCNT register’s high byte, followed by the I2CxCNT register’s low byte. If the order of these two bytes is switched, the value loaded into the I2CxCNT register will not be correct.
In Host Reception mode, the first two bytes received from the client are loaded into both high and low bytes of the I2CxCNT register in addition to the I2CxRXB register. The value of the Acknowledge Data (ACKDT) bit is used as the host’s acknowledgement response to prevent a false NACK from being generated before the I2CxCNT register is updated with the new count value.

In Client Reception mode, the first two bytes received after a receiving a matching 7-bit or 10-bit address are loaded into both high and low bytes of the I2CxCNT register in addition to the I2CxRXB register, and the value of the ACKDT bit is used as the client’s acknowledgement response.

In Client Transmit mode, the first two bytes loaded into I2CxTXB following the reception of a matching 7-bit or 10-bit address are transferred into both high and low bytes of the I2CxCNT register in addition to the transmit shift register.