Function uart 

pub fn uart(
    clocks: &mut GenericClockController,
    baud: impl Into<Hertz>,
    sercom: UartSercom,
    pm: &mut PM,
    uart_rx: impl Into<UartRx>,
    uart_tx: impl Into<UartTx>,
) -> Uart

Convenience for setting up the labelled RX, TX pins to operate as a UART device running at the specified baud.