Universal Asynchronous Receiver/Transmitter (UART) is a fairly simple protocol with two lines (transmit and receive) going between two devices. The lines are normally held high until one of the ...

for sercom3 pad 1 is pin 1 so RX is pin 1 (SERCOM_RX_PAD_1 = this sercom is uart with RX on pad 1) for sercom3 pad 0 is pin 0 so TX is pin 0 (UART_TX_PAD_0 = uart TX pad is pad 0) the first two ...