57.9.3.11 TWI High-Speed Host

TWI High-Speed Host mode is enabled when FLEX_TWI_CR.HSEN=1 and FLEX_TWI_CR.MSEN=1. TWI High-Speed mode operation is similar to TWI operation, with the following exceptions:

1. A host code is sent first at normal speed before enabling TWI High-Speed mode.
2. Arbitration is only possible during host code transmission.
3. When TWI High-Speed mode is active, an internal mechanism is enabled to shorten the SCL signal rise time
4. When TWI High-Speed mode is active, clock stretching is only allowed after acknowledge (ACK), not-acknowledge (NACK), START (S) or repeated START (Sr) (as a consequence, overflow can happen).
5. When TWI High-Speed mode is active, the data transfer uses the TWI High Speed mode bit rate which can be defined in FLEX_TWI_HSCWGR.