42.7.5.7.1 Read/Write Operation
A TWIHS high-speed frame always begins with the following sequence:
- START condition (S)
- Host Code (0000 1XXX)
- Not-acknowledge (NACK)
When the TWIHS is programmed in Client mode and TWIHS High-speed mode is activated, Host code matching is activated and internal timings are set to match the TWIHS High-speed mode requirements.