21.4.2.5 Error Handling

The module has the capability to automatically detect and flag framing errors and CRC mismatch. A framing error is the detection of a status or data nibble period, less than 12 ticks or greater than 27 ticks. If a framing error is detected, the FRMERR bit (SENTxSTAT[2]) is set and a receive error interrupt is generated. After a framing error has been detected, the module clears SYNCTXEN (SENTxSTAT[0]) and begins looking for another valid Sync period. The FRMERR bit remains set until another valid Sync period has been detected and SYNCTXEN = 1. The application may optionally clear the FRMERR bit.

Note: If the PPP bit is set, the module will not generate a framing error on successive valid Sync pulses. This is due to the possibility that a Pause pulse could be interpreted as a valid Sync and the following actual Sync pulse could be interpreted as a frame error. Framing errors for nibble data will still be detected when PPP = 1.

If CRC verification fails, the CRCERR bit (SENTxSTAT[3]) is set and a receive error interrupt is generated. The CRCERR bit remains set until a valid Sync period for a new message has been received. Software may optionally clear the CRCERR bit. The CRCEN bit (SENTxCON1[8]) must be set to receive an interrupt on a CRC error.