Blinky runs on DK, but not on external Seeed Xiao nRF52840

RE: Blinky runs on DK, but not on external Seeed Xiao nRF52840

IrvingC — Tue, 20 Jan 2026 13:54:46 GMT

Was only configured in debug, now in the build for normal running. So now everything's working, have 3 active threads plus main all happily talking to each other. Now to port my application code! Thanks a lot for your help 😀, much appreciated.

RE: Blinky runs on DK, but not on external Seeed Xiao nRF52840

Kenneth — Mon, 19 Jan 2026 15:42:07 GMT

[quote user="IrvingC"]though still not able to get printk coming out of the Xiao usb port - any thoughts on that?[/quote]

Hello,

I believe that should be possible by following \zephyr\boards\common\usb\cdc_acm_serial.dtsi

Also, have you set CONFIG_PRINTK=y?

Kenneth

RE: Blinky runs on DK, but not on external Seeed Xiao nRF52840

IrvingC — Mon, 19 Jan 2026 12:50:38 GMT

Thanks Kenneth. I had looked at the partition manager info but hadn't got the naming convention quite right. That's working fine now, and debugging now working as well, though still not able to get printk coming out of the Xiao usb port - any thoughts on that?

In an ideal world I'd spend a couple of weeks working through the tutorials, but this is a rush job so have to get to grips with it ASAP. I've spent a few long nights reading; the Zephyr tool-chain is, understandably, a much more complex environment than the pre-configured embedded RTOS on the ESP32 but porting the existing code I don't see as a problem once I've got the platform basics working.

RE: Blinky runs on DK, but not on external Seeed Xiao nRF52840

Kenneth — Mon, 19 Jan 2026 10:05:37 GMT

Hello,

If you haven't already I recommend to check out our decAcademy: https://academy.nordicsemi.com/ I also recommend to start with an nRF52840-DK before moving to a module or own board, then you can get familiar with the architecture and development environment before you proceed with the board level modifications.

In specific information about partition manager is covered in this lesson:
https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-8-sysbuild/topic/sysbuild-partition-manager/

Kenneth

RE: Blinky runs on DK, but not on external Seeed Xiao nRF52840

IrvingC — Sun, 18 Jan 2026 19:28:36 GMT

Hi Kenneth,

That partially helped in that it doesn't appear to generate the UF2 file anymore, however the partitions still stay fixed and this seems to be because late in the build, long after any configuration has occurred I see:

-- Configuring done
-- Generating done
-- Build files have been written to: C:/Users/skype/blinky_seeed/build/blinky_seeed
-- Found partition manager static configuration : C:/ncs/v3.2.1/zephyr/boards/seeed/xiao_ble/pm_static.yml
-- Configuring done
-- Generating done

which seems to wipe out any previous partition management

I can compile for the nrf52840dk and that runs but it has the wrong gpio number (13 not 26) so the LED0 doesn't flash (but oddly dLED2 on P0.06 does weakly). I used an overlay to change the pin that eventually worked, though the whole thing seems flaky, sometimes the build failed claiming a device driver wasn't found which had nothing to do with the overlay. But that's not a long term solution as I need the USB & UART to work and it seems that's not working without the bootloader installed.

Or how do I get printk statements out to the PC from the external board - either via the DK or preferably through it own USB port? because at the moment what comes out on COM12 is from the program on the DK not the external board.

So, do I need to go back to the default Xiao BLE configuration, with the bootloader in place; I don't need it but it may be the only way to get this to work, or how do I sort the partitioning out so the build doesn't require the bootloader and get the local USB/UART working...?

RE: Blinky runs on DK, but not on external Seeed Xiao nRF52840

Kenneth — Wed, 14 Jan 2026 16:23:28 GMT

Hello,

I don't have the module in question, but if you set those two kconfig options to =n and it doesn't compile in, then it sounds to me that you need to make sure the change is saved and perform a pristine build (e.g. delete build folder). Instead of modifying the board files directly you can simply put in prj.conf:

CONFIG_BUILD_OUTPUT_UF2=n

CONFIG_USE_DT_CODE_PARTITION=n

CONFIG_FLASH_LOAD_OFFSET=0

Alternatively try to build for the nrf52840dk for test and program it instead.

Kenneth