Is it possible to use softDevice on nRF52840 without 32k crystal?

RE: Is it possible to use softDevice on nRF52840 without 32k crystal?

Artak — Tue, 14 Nov 2017 04:26:37 GMT

I'm using the 14.1 version and I was able to make it working after changing the value of NRF_SDH_CLOCK_LF_SRC. Thanks :)

RE: Is it possible to use softDevice on nRF52840 without 32k crystal?

Jørgen Holmefjord — Mon, 13 Nov 2017 10:07:59 GMT

Which SDK version are you using? Note that the clock source used by the softdevice is not the one you configure in the CLOCK peripheral settings in sdk_config.h. In SDK 14.x.0, you can configure clock source for the softdevice using the sdk_config.h macros NRF_SDH_CLOCK_LF_SRC, NRF_SDH_CLOCK_LF_RC_CTIV, and NRF_SDH_CLOCK_LF_RC_TEMP_CTIV.

RE: Is it possible to use softDevice on nRF52840 without 32k crystal?

Artak — Fri, 10 Nov 2017 15:46:56 GMT

Hi Jørgen,

I have tried to perform the following changes into ble_app_blinky example:

Changed the value of macro CLOCK_CONFIG_LF_SRC to 0 from sdf_config.h
Added call to nrf_drv_clock_init() at the very first line of main() function.

But the example still works properly on PDK board only if the 32K xtal is connected.

Do I miss something important?

RE: Is it possible to use softDevice on nRF52840 without 32k crystal?

Jørgen Holmefjord — Fri, 10 Nov 2017 07:32:38 GMT

Hi,

Yes, you can use 32.768 kHz RC oscillator (LFRC) as the clock source.

Best regards,

Jørgen