Break and Sync Transmit Sequence

The following sequence will start a message frame header made up of a Break, followed by an auto-baud Sync byte. This sequence is typical of a LIN bus master.

  1. 1.Configure the EUSART for the desired mode.
  2. 2.Set the TXEN and SENDB bits to enable the Break sequence.
  3. 3.Load the TXxREG with a dummy character to initiate transmission (the value is ignored).
  4. 4.Write ‘55h’ to TXxREG to load the Sync character into the transmit FIFO buffer.
  5. 5.After the Break has been sent, the SENDB bit is reset by hardware and the Sync character is then transmitted.

When the TXxREG becomes empty, as indicated by the TXxIF, the next data byte can be written to TXxREG.