I'm using a SAM D20 Xplained pro board and having some difficulty understanding how the muxing works. I'm using Atmel Studio.
This configuration works for me with SERCOM4 configured as USART.
config_usart.mux_setting = USART_RX_1_TX_0_XCK_1;
config_usart.pinmux_pad2 = PINMUX_PB08D_SERCOM4_PAD0; //TX
config_usart.pinmux_pad3 = PINMUX_PB09D_SERCOM4_PAD1; //RX
What should my settings be if I want to use SERCOM3 as a USART with PA03 = TXD and PA04 = RXD?