37.3.12.1.2 ACNTMD = 1 (8 bits are
loaded into the high byte of I2CxCNT)
In Host Transmit mode, the first byte following either the 7-bit or 10-bit client address is transferred from I2CxTXB into the high byte of the I2CxCNT register in addition to the transmit shift register.
In Host Reception mode, the first byte received from the client is loaded into the high byte 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 byte received after receiving a matching 7-bit or 10-bit address is loaded into the high byte 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 byte loaded into I2CxTXB following the reception of a matching 7-bit or 10-bit address is transferred into the high byte of the I2CxCNT register in addition to the transmit shift register.