Asynchronous Transmission Setup

Use the following steps as a guide for configuring the UART for asynchronous transmissions.

  1. 1.Initialize the UxBRG register pair and the BRGS bit to achieve the desired baud rate.
  2. 2.Set the MODE bits to the desired Asynchronous mode.
  3. 3.Set the TXPOL bit if inverted TX output is desired.
  4. 4.Enable the asynchronous serial port by setting the ON bit.
  5. 5.Enable the transmitter by setting the TXEN Control bit. This will cause the UxTXIF Interrupt flag to be set.
  6. 6.If the device has PPS, configure the desired I/O pin RxyPPS register with the code for the TX output.
  7. 7.If interrupts are desired, set the UxTXIE Interrupt Enable bit in the respective PIE register. An interrupt will occur immediately provided that global interrupts are also enabled.
  8. 8.Write one byte of data into the UxTXB register. This will start the transmission.
  9. 9.Subsequent bytes may be written when the UxTXIF bit is ‘1’.
Figure 1. UART Asynchronous Transmission
Figure 2. UART Asynchronous Transmission (Back-to-Back)