Device Tree, proj.conf and strange uart behaviour

RE: Device Tree, proj.conf and strange uart behaviour

Jas39 — Thu, 18 Apr 2024 14:21:35 GMT

When set in the other order the buildsystem warned that CONFIG_UART_0_INTERRUPT_DRIVEN=y when setting CONFIG_UART_0_ASYNC=y

I switched order and did not investigate further. Your statement is inline with my expectations on build that order should not matter.

RE: Device Tree, proj.conf and strange uart behaviour

Vidar Berg — Thu, 18 Apr 2024 14:04:03 GMT

Hm, the order should not matter. I recommend checking the generated .config file in build/zephyr if you want to verify if the symbol is set correctly. You should also see Kconfig warnings in the build log if assignments from your prj.conf are ignored due to missing dependencies or conflicting configurations.

RE: Device Tree, proj.conf and strange uart behaviour

Jas39 — Thu, 18 Apr 2024 13:50:48 GMT

Thanks Vidar.

Worth noting is that order seems to be important, this sequence works:

# Expilict async on uart0 to override USB CDC

CONFIG_UART_0_INTERRUPT_DRIVEN=n

CONFIG_UART_0_ASYNC=y

RE: Device Tree, proj.conf and strange uart behaviour

Vidar Berg — Thu, 18 Apr 2024 12:37:21 GMT

Hello,

The xiao ble sense board is using USB CDC for console, logging, etc, and the USB stack is not compatible with the Asynchronous API, only the Interrupt-driven API. However, it should be possible to disable enable the ASYNC api for the uart0 node by setting CONFIG_UART_0_INTERRUPT_DRIVEN=n and CONFIG_UART_0_ASYNC=y in your prj.conf file.

Best regards,

Vidar

Edit: Replaced the word 'disable' with 'enable'. Attached below is also a modified version of the central UART sample I created to support the USB interface if you prefer that over using UART. (Note: it requires SDK v2.5.2 to build, as it has not been ported to v2.6.0).

devzone.nordicsemi.com/.../central_5F00_uart_5F00_w_5F00_usb_5F00_ncs_5F00_2_5F00_5_5F00_2.zip