RTC drift when LF-RC is chosen in sdk-config.h

[Bhumika]

Hello,

I can see RTC drift of around 14 seconds in 1 hr when I select the internal RC oscillator in sdk-config of nrf-calender example.

Is this much drift expected? In my perception, 14 seconds of drifts in an hour is very high. The Time calculated using the nrf-calender example is ahead of the actual time by 14 seconds in an hour.

I am using nrf52840 dk-board for running the example.

Please suggest what can be done to sync time correctly.

[Vidar Berg]

Hello,

Assume calibration is not enabled in this example? The RC must be calibrated periodically to reach the +/- 500 ppm accuracy (Calibrating the 32.768 kHz RC oscillator).   Calibration is usually taken care of by the Softdevice, but if you use an application without a Softdevice you need to enable calibration yourself.

Here's an example where calibration is enabled without the Softdevice:

6201.SDK17.0.2_peripheral_rtc_w_rcosc.zip