How to set LFRC as the LFCLK clock source for nRF52840

[TsuKawa]

Hello,

I am using "nRF Connect SDK v2.3.0" with "nRF52840".
I would like to set LFRC as the LFCLK clock source.
Please let me know if the following <prj.conf> settings are sufficient in the environment below.

<prj.conf>

CONFIG_SYSTEM_CLOCK_WAIT_FOR_STABILITY=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y
CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y

<Enviroment>
Hardware: custom board based on "u-blox EVK-NINA-B3"
Software: nRF Connect SDK v2.3.0.

I would appreciate it if you could let me know about any deficiencies or points to note.

[Vidar Berg]

Hello,

Only CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y is needed. CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM will be selected automatically when RC is selected as can be seen here link. CONFIG_SYSTEM_CLOCK_WAIT_FOR_STABILITY is also enabled by default, see https://github.com/nrfconnect/sdk-zephyr/blob/328411d85839340607fe033fa4de4f59cb2eb038/drivers/timer/Kconfig.nrf_rtc#L45. 

Best regards,

Vidar

[TsuKawa]

I appreciate for your help. 

I will give it a try.