RTC reverts back to last set value when power removed


#1

Why does the internal RTC back to the last value set when power is removed from the device?

For example - I set the time/date to

AT+CCLK=“07/09/21,13:02:00”

and ran it for twenty minutes. I then removed the power. After a while I reapplied power and read the time.

at+cclk?
at+cclk?

+CCLK: “07/09/21,13:02:24”

I can understand the RTC stopping at the time the power was removed but why does it revert back to the last set time???


#2

Because it doesn’t waste flash write cycles every time the RTC ticks or tocks probably.


#3

Interesting. In older versions it went back to a default time (e.g. some time in 1998, which I found in the oldest module we still have in use.)

Best Regards,
Jan