How to use the internal RTC on nRF52833 SoC to keep system time across reboots

Hello,

I need your help on how to use the internal RTC on nRF52833 SoC to keep the system time under zypher.

I need the RTC to keep its time after,

1- Reboots

2- Sleep using k_sleep( Duration ) 

3- System Off mode, although this use case may not be necessary but still interested if it is possible.

Finally, looking at the nRF52833 RTC registers I could not find a way of setting the time. Is there one?

Kind regards

Mohamed