NRF52840 External crystal oscillator invalid

[anzhongxin]

Hi:

52840 with softdevice, I use External low frequency oscillator  (32.768K) ,the system run normal,but some days later,system can't run. So,I find the problem，the problem is the external crystal oscillator cannot start, softdevice enable failed!

reprogram,the problem remains, but I change the cofing  NRF_SDH_CLOCK_LF_SRC = 0  use internal RC or replace the MCU,   system can run normal.

I use s140_nrf52_6.1.0_softdevice.hex!

[Susheel Nuguru]

Seems like your external crystal is not starting correctly.

You should check the clock accuracy of your XTAL in the spec given to you by its manufacturer and check if you are enabling the softdevice with the correct PPM accuracy settings matching your XTAL.