35.4.2.1 LIN Client Receiver

When the Client process is a Receiver, the software performs the following tasks:

  • The UxP3 register is written with a value equal to the number of data bytes to receive
  • The C0EN bit is set or cleared to select the appropriate checksum. This must be completed before the Start bit of the checksum byte is received.
  • Each byte of the process response is read from UxRXB when UxRXIF is set

The UART updates the checksum on each received byte. When the last data byte is received, the computed checksum total is stored in the UxRXCHK register. The next received byte is saved in the receive FIFO and added with the value in UxRXCHK. The result of this addition is not accessible. However, if the result is not all ‘1’s, the CERIF bit is set. The CERIF flag persists until cleared by software. Software needs to read UxRXB to remove the checksum byte from the FIFO, but the byte can be discarded if not needed for any other purpose.

After the checksum is received, the UART ignores all activity on the RX pin until a Break starts the next transaction.