nRF51822 with 32MHz crystal in system OFF mode

RE: nRF51822 with 32MHz crystal in system OFF mode

Remo — Thu, 09 Jul 2015 13:21:23 GMT

Thank you for the clarification!

RE: nRF51822 with 32MHz crystal in system OFF mode

Stefan Birnir Sverrisson — Wed, 08 Jul 2015 14:30:47 GMT

The designers have informed me that only setting the

NRF_CLOCK->XTALFREQ = 0xFFFFFF00U;

is not guaranteed to work. You would need to set the UICR register for reliable operation. At this point I do not realize either the use for NRF_CLOCK->XTALFREQ since you always need to set the UICR register.

RE: nRF51822 with 32MHz crystal in system OFF mode

Remo — Wed, 08 Jul 2015 13:17:19 GMT

Hi Stefan

Thank you for your answer. As you suggested, I set the clock frequency in the CLOCK and the UICR registers. It works, but it also worked when I set the frequency only in the UICR register. For what is the NRF_CLOCK->XTALFREQ register actually needed? What exactly was the problem when the frequency was only set in the NRF_CLOCK->XTALFREQ register and the system OFF mode was activated?

Kind regards

RE: nRF51822 with 32MHz crystal in system OFF mode

Stefan Birnir Sverrisson — Wed, 08 Jul 2015 11:56:32 GMT

Thank you for your feedback.

I have updated the linked thread with a correction. Please try that and report your result.