Are there interfaces reserved in the Datatime module for users to add an external RTC device as a clock source?

[Harvey Zheng]

Hi,

I am using NCS v1.9.0 and have a question about datatime module.

It seems to have NTP and Modem clock sources, but I don't want to use either clock source. I have an external RTC device that I want to use as a clock source, but I didn't find the unified function interface like Zephyr sensor.h. Is there a way to extend the clock source without modifying the source code?

Thanks! 

[Elfving]

Hello!

I believe the internal RTC is always used (through clock_gettime). That in turn is regularly set from NTP/modem if configured for that. It can also be set from an arbitrary external source, with date_time_set. I think the main purpose of date_time lib is to get time from either LTE network or NTP server. But if the you do not want to use that, I don't understand why you would use the date_time lib? 

Zephyr do have some APIs for Real Time Clocks here btw.

Regards,

Elfving

[Harvey Zheng]

Hi,

Thanks，Elfving. I use data_time lib, because I don't want the application to care what clock source is used by the drivers layer, but choose at compile time just like choose LTE or NTP in date_time lib.

Now I use the externak RTC, and I can easily switch to LTE network or NTP server in the future. I think it's more flexible.

[Elfving]

I see. Sounds good! 

Regards,

Elfving