nRF9160 Route LFCLK to External Device

[Akash Patel]

Hi team,

Is it possible to route the low frequency clock inside the nRF9160 to an external device? If not, then the only option is to generate the clock using the timer peripheral as we have suggested in the past for nRF52 devices such as here?

Regards,

Akash

[ovrebekk]

Hi Akash

There is no easy way to do this unfortunately, as the nRF9160 doesn't have any new features for doing this that were not present on the nRF52. 

The only way to generate an accurate 32.768kHz pulse on a pin based on the LF clock is to use the RTC TICK event to generate the raising flank of the GPIO, and use a TIMER module to generate the falling flank approximately half a period later. 

If you use the RTC TICK event for both the raising and falling flank you get a simpler and more efficient solution, but then the output will be at half the frequency. 

Best regards
Torbjørn