Seeeduino Xiao Zephyr Problem

maxgerhardt · February 14, 2022, 7:01pm

Since PlatformIO declares

platformio/platform-atmelsam/blob/develop/boards/seeed_xiao.json#L30-L32


      
          "variant": "XIAO_m0",
          "zephyr": {
             "variant": "seeeduino_xiao"

the used Zephyr version is seeduino_xiao, which declares as its serial and console output device as

github.com

zephyrproject-rtos/zephyr/blob/main/boards/arm/seeeduino_xiao/seeeduino_xiao.dts#L15-L17


      
          
          
	chosen {
          		zephyr,console = &sercom4;

which is a hardware UART at 115200 baud, not USB, on the pins

github.com

zephyrproject-rtos/zephyr/blob/main/boards/arm/seeeduino_xiao/seeeduino_xiao.dts#L51-L59


      
          
          
&sercom4 {
          	status = "okay";
          	compatible = "atmel,sam0-uart";
          	current-speed = <115200>;
          	rxpo = <1>;
          	txpo = <0>;
          
          
	pinctrl-0 = <&sercom4_uart_default>;

PB9 and PB8, which, per schematic is the pin labeled “A7” (RX) and “A8” (TX).

So, if you connect a USB UART adapter to thoses pins (and GND) and open the serial monitor at 115200 baud (monitor_speed = 115200 in the platformio.ini), you should see that output.

For console over the USB-CDC serial, see zephyr/samples/subsys/usb/console at main · zephyrproject-rtos/zephyr · GitHub.