34.5.1 I/O Lines

Using the USART’s I/O lines requires the I/O pins to be configured using the I/O Pin Controller (PORT).

When the SERCOM is used in USART mode, the SERCOM controls the direction and value of the I/O pins according to the table below. If the receiver or transmitter is disabled, these pins can be used for other purposes.

Table 34-2. USART Pin Configuration
PinPin Configuration
TxDOutput
RxDInput
XCKOutput or input

The combined configuration of PORT and the Transmit Data Pinout and Receive Data Pinout bit fields in the Control A register (CTRLA.TXPO and CTRLA.RXPO, respectively) will define the physical position of the USART signals in Table 34-2.