How can I change the 32.768KHz Low Power Clock Source using nRF Connect SDK v2.x?

With nRF Connect SDK v2.0.0 and later only VS Code is made available as an IDE as VS Code provides many features including both Command Line Interface (CLI) and Graphical User Interface (GUI) in one environment.

Prior to nRF Connect SDK, the 32.768KHz source in nRF5 SDK applications defaulted to using the external crystal oscillator. The BL65x DVK’s populate an external 32.768KHz crystal but it is not connected via open solder bridges. Therefore, either the solder bridges need to be shorted to make the external crystal connection or change the clock source to internal RC Oscillator via the sdk_config.h file.

With nRF Connect SDK the correct 32KHz clock source is selected depending on the EVK. For BL654 DVK examples are built using internal RC oscillator. On BL5340 DVK the external crystal oscillator is selected as the DVK does close the solder bridge pads.

If the 32KHz clock source needs to be changed an application can change accordingly in the prj.conf file of the project. The following direct dependencies need to be added to prj.conf to override the default clock configuration.

External Crystal Oscillator and accuracy selection:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_50PPM=y

Internal RC Oscillator and accuracy selection:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y

Kconfig dependencies can be found:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.3.0/kconfig/index.html