UART Configuration Custom Board nRF5340

[dario.sortino]

Hello!

I have a custom board that I am trying to set up but I'm not entirely sure what to do.

In my board, I have an nRF5340 SoC, that has 2 interfaced with the external world: a micro USB port (connections are done exactly like the DK), and a UART with RX in PIN 1.00, and TX in PIN 1.01.

I want to use the micro USB to print something to a console as a "debugging" tool, and the more classic UART to print some different stuff.

What are the devicetree and defconfig configurations for this kind of usecase? I think I should set two different UART interface in the dts (&uart0 and &uart1?), but how do I tell one UART to go trough USB? In the DK dts I can see

chosen {
		zephyr,console = &uart0;
		zephyr,shell-uart = &uart0;
		zephyr,uart-mcumgr = &uart0;
		zephyr,bt-mon-uart = &uart0;
		zephyr,bt-c2h-uart = &uart0;
		zephyr,bt-hci-rpmsg-ipc = &ipc0;
	};

but I can't figure out what exactly I need to use in my custom board.

Any help would be appreciated

[Kenneth]

Hello,

I suggest to take a look at the applications\matter_weather_station project for the Thingy:53.

In specific you can find that there is an overlay file that will override from default uart to usb cdc uart for logging/shell:

Default using uart (\boards\arm\thingy53_nrf5340)

        zephyr,console = &uart0;
        zephyr,shell-uart = &uart0;

To usb cdc uart (\matter_weather_station\configuration\thingy53_nrf5340_cpuappapp.overlay)

        zephyr,console = &cdc_acm_uart0;
        zephyr,shell-uart = &cdc_acm_uart0;

In addition I can find in the prj.conf the following:

# Configure UART logging and shell
CONFIG_LOG=y
CONFIG_LOG_MODE_DEFERRED=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_PRINTK=y
CONFIG_LOG_PROCESS_THREAD_STACK_SIZE=1024
CONFIG_LOG_PROCESS_THREAD_STARTUP_DELAY_MS=4000
CONFIG_LOG_BUFFER_SIZE=8192
CONFIG_LOG_FUNC_NAME_PREFIX_DBG=n
CONFIG_MATTER_LOG_LEVEL_DBG=y
CONFIG_SHELL=y
CONFIG_SHELL_LOG_BACKEND=y

# Enable USB CDC ACM
CONFIG_USB_DEVICE_STACK=y
CONFIG_USB_DEVICE_REMOTE_WAKEUP=n
CONFIG_USB_DEVICE_PRODUCT="Thingy:53 Matter Weather"
CONFIG_USB_DEVICE_VID=0x1915
CONFIG_USB_DEVICE_PID=0x530D
CONFIG_USB_CDC_ACM=y
CONFIG_USB_CDC_ACM_LOG_LEVEL_ERR=y
CONFIG_USB_DEVICE_LOG_LEVEL_ERR=y
CONFIG_UART_LINE_CTRL=y
CONFIG_SHELL_BACKEND_SERIAL_INIT_PRIORITY=51
CONFIG_SHELL_BACKEND_SERIAL_CHECK_DTR=y

Best regards,
Kenneth

[dario.sortino]

&zephyr_udc0 {
	cdc_acm_uart0: cdc_acm_uart0 {
		compatible = "zephyr,cdc-acm-uart";
	};
};

Hi Kenneth,

I assume that I need to define a node label as above (I found this also here https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/subsys/usb/console), but when compiling I have a parse error having the zephyr_udc0 undefined.

How can I solve this behaviour?

[Kenneth]

I missed that. Have you tried a pristine build?

Kenneth

[dario.sortino]

Yes, I have tried that. I can't get where it takes the reference from.

[Kenneth]

I am not sure which ncs version you are working on, but have you tried for instance to build the nrf\samples\bluetooth\peripheral_uart\?

Edit: Have you made your own board file or are you building for DK?

Kenneth

[dario.sortino]

I'm on nRF Connect SDK v2.1.0, and I made the board file following this guide

here https://www.youtube.com/watch?v=ufjv2NaLfN8

The example you mention builds just fine (using nrf5340dk as board in the board configuration)

[Kenneth]

Do you have the following in your .dts file:

zephyr_udc0: &usbd {
compatible = "nordic,nrf-usbd";
status = "okay";
};

[dario.sortino]

That did the trick, thank you so much!