57.9.6.7 TWI Single Data Access

When FIFO is enabled and a byte access is performed in FLEX_TWI_THR, one byte is written in the FIFO. The same behavior applies for FLEX_TWI_RHR.

See TWI Transmit Holding Register and TWI Receive Holding Register.

However, it is possible to write/read multiple data each time FLEX_THR_THR/FLEX_US_RHR is accessed. See TWI Multiple Data Access.