31.5.2.1 Receiver Reset, Enable and Disable
After device reset, the RXLP is disabled and must be enabled before being used. The receiver can be enabled by setting bit RXEN in the Control register (RXLP_CR). At this command, the receiver starts looking for a start bit.
The programmer can disable the receiver by setting bit RXLP_CR.RXDIS. If the receiver is waiting for a start bit, it is immediately stopped. However, if the receiver has already detected a start bit and is receiving the data, it waits for the stop bit before actually stopping its operation.
The receiver can be put in reset state by setting bit RXLP_CR.RSTRX. In this case, the receiver immediately stops its current operations and is disabled, whatever its current state. If RSTRX is applied when data is being processed, this data is lost. After initiating a reset it is mandatory to clear bit RXLP_CR.RSTRX.