I'm using an RTC as I explained in this thread.
Our device have a battery in VBAT, so the RTC still works when the device it's power off. But after a power on the RTC can loss up to 1 second, I think due we configure the RTC again.
Using backup registers we can detect if we come for the first power on (and we have to configure the RTC) or not (and maybe we can avoid configuring the RTC).
How we can avoid this delay? Which should be the configuration of the RTC in the second case?