NRF54L15-DK deep sleep, wake up via RTC

RE: NRF54L15-DK deep sleep, wake up via RTC

Håkon Alseth — Wed, 03 Sep 2025 10:32:49 GMT

Hi,

Thanks for sharing the log.

The symbol:

[quote userid="147802" url="~/f/nordic-q-a/124130/nrf54l15-dk-deep-sleep-wake-up-via-rtc/547609"]warning: attempt to assign the value 'y' to the undefined symbol GRTC_WAKEUP_ENABLE[/quote]

is local to the sample that I shared here:

[quote userid="2115" url="~/f/nordic-q-a/124130/nrf54l15-dk-deep-sleep-wake-up-via-rtc/547597"]zephyr/samples/boards/nordic/system_off[/quote]

Here's the local definition of it:

https://github.com/nrfconnect/sdk-zephyr/blob/main/samples/boards/nordic/system_off/Kconfig#L16

If you are trying to integrate it into your own project, just copy the code directly without the guard for "GRTC_WAKEUP_ENABLE" symbol.

Kind regards,

Håkon

RE: NRF54L15-DK deep sleep, wake up via RTC

Nikollao — Wed, 03 Sep 2025 10:22:43 GMT

C:/ncs/button_k_sleep/prj.conf:8: warning: attempt to assign the value 'y' to the undefined symbol GRTC_WAKEUP_ENABLEParsing C:/ncs/v3.1.0/zephyr/Kconfig
Loaded configuration 'C:/ncs/v3.1.0/zephyr/boards/ezurio/bl54l15u_dvk/bl54l15u_dvk_nrf54l15_cpuapp_ns_defconfig'
Merged configuration 'C:/ncs/button_k_sleep/prj.conf'
Merged configuration 'C:/ncs/button_k_sleep/build/button_k_sleep/zephyr/.config.sysbuild'

error: Aborting due to Kconfig warnings

CMake Error at C:/ncs/v3.1.0/zephyr/cmake/modules/kconfig.cmake:377 (message):
command failed with return code: 1
Call Stack (most recent call first):
C:/ncs/v3.1.0/nrf/cmake/modules/kconfig.cmake:83 (include)
C:/ncs/v3.1.0/zephyr/cmake/modules/zephyr_default.cmake:131 (include)
C:/ncs/v3.1.0/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
C:/ncs/v3.1.0/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:97 (include_boilerplate)
CMakeLists.txt:2 (find_package)

-- Configuring incomplete, errors occurred!

RE: NRF54L15-DK deep sleep, wake up via RTC

Håkon Alseth — Wed, 03 Sep 2025 10:21:02 GMT

Can you share the output?

RE: NRF54L15-DK deep sleep, wake up via RTC

Nikollao — Wed, 03 Sep 2025 10:20:04 GMT

Sorry my mistake, build fails. so I am trying to write CONFIG_GRTC_WAKEUP_ENABLE=y in my .conf file but this does not build. I intended to flash only, not debug.

RE: NRF54L15-DK deep sleep, wake up via RTC

Håkon Alseth — Wed, 03 Sep 2025 10:18:15 GMT

Hi,

Happy to help out.

Debugging while entering systemoff is generally not easy, because this is a mode where (mostly) combinatory logic is powered + the GRTC, while the active SWD debug interface requires certain CPU parts to run to work as intended.

Due to this, we have a "emulated system off mode", which will not work entirely as the function does without debug mode:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/pmu.html#ariaid-title5

We recommend that you add a while(1) loop after, to ensure that you do not debug/step further.

Kind regards,

Håkon

RE: NRF54L15-DK deep sleep, wake up via RTC

Nikollao — Wed, 03 Sep 2025 10:05:33 GMT

Hi, Thanks for the response. When setting CONFIG_GRTC_WAKEUP_ENABLE=y in the prj.conf file, debug fails. Any idea why? Sorry, I am new to the NRF environment.

RE: NRF54L15-DK deep sleep, wake up via RTC

Håkon Alseth — Wed, 03 Sep 2025 09:49:57 GMT

Hi,

There is a sample that shows wakeup from system off with the nRF54L-series devices in zephyr/samples/boards/nordic/system_off, where specifically this logic is what enables the GRTC to run in systemoff mode:

https://github.com/nrfconnect/sdk-zephyr/blob/main/samples/boards/nordic/system_off/src/main.c#L100-L108

Remember to set "CONFIG_GRTC_WAKEUP_ENABLE=y" when evaluating.

Kind regards,

Håkon