Enabling internal clock for NRF 52832

[Sachin]

Hi,

 I am trying to enable the internal clock for NRF 52832 (BMD-350) module.

The configuration option for the clock has

1. RC Oscillator 

2. Crystal Oscillator

3. Synthesized from HFCLK

4. External Low Swing

5. External full swing

The SoftDevice SDK is 1.9.1. Please suggest how I should enable the same 

Thanks

[Einar Thorsrud]

Hi,

You enable the RC by setting CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y in for instance your prj.conf. This should implicitly set CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n, but you can also do it explicitly. The same applies to calibration. This should automatically be enabled but you can do it with CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC_CALIBRATION=y. Lastly, set the accuracy to 500 ppm using CONFIG_CLOCK_CONTROL_NRF_K32SRC_500PPM=y, as this is the accuracy of the internal 32.768kHz RC oscillator.

[Sachin]

Thanks for the quick support Einar Thorsrud (with) . When I enable all the configurations above.

Getting the following compile time error

#error "Two-stage LFXO start procedure enabled but LFCLK source is not set to LFXO!"

[Einar Thorsrud]

Where do you get that warning from (which file)? I am not able to find it when searching through the SDK code, so I cannot check why you get it. It is clearly related to some code that rely on the LFXO though, which for some reason is included. If this is from some code that is not part of the SDK, than please explain or share it.

Also, my comment was about how to select LRFC in general in the nRF Connect SDK, you mentioned a lot of keywords so I am not sure if that is what you wanted, but that was my assumption (for instance synthesized clock is typically not useful due to current consumption constraints, and swing configurations are relevant for external clocks (not just crystals). You can see all relevant configuration options by searching for CONFIG_CLOCK_CONTROL_NRF_ in the Kconfig search.