45.6.10.8.7 End of Frame Condition
The USART configured in LON mode terminates the frame with a 3 tbit long Manchester code violation. After sending the last CRC bit, it maintains the data transitionless during three bit periods.
While receiving data the USART configured in LON mode will detect an end of frame condition after a teof transitionless Manchester code violation. US_LONMR.EOFS can configure teof.