Using FreeRTOS without external 32,768 Hz crystal on nrf52840

[dao]

I am developing a firmware on a nrf52840 board with FreeRTOS. Unfortunately, due to a mistake during the development process, the board misses the XTAL 32,768 Hz. 

Is there any way we can configure FreeRTOS without this XTAL? 

Thanks a lot.

[bjorn-spockeli]

Hi Dao, 

Yes, you can run any BLE example ( regardless if you're using FreeRTOS or not) without the external XTAL 32,768kHz, you can use the internal 32kHz RC oscillator. This is done by setting the following defines in the sdk_config.h file.  

#define NRF_SDH_CLOCK_LF_SRC 0

#define NRF_SDH_CLOCK_LF_RC_CTIV 16

#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2

#define NRF_SDH_CLOCK_LF_ACCURACY 0 

Best regards

Bjørn

[dao]

Thanks Bjorn, it worked.