I keep lossing my rtc datetime, when on lipo power.
But on usb, i don’t see any issue.
The schematic of the RAK12002 show the super caps charge from 3V3 (not 3V3_S).
When i have a RAK4631/RAK19001 and the 4631 spents 99% for the time deep sleep, is 3V3 bus still powered and charging the caps?
Not sure why you loose RTC time when running from battery, it should not happen.
3V3 is always on independent whether the RAK4631 is in deep sleep or the supply is from USB or battery.
What is your initialization for the RTC? My default code for the RTC is RAK12002_rtc.cpp
Maybe this setting helps:
rtc.writeToRegister(0x35, 0x00);
rtc.writeToRegister(0x37, 0xB4); // Direct Switching Mode (DSM): when VDD < VBACKUP, switchover occurs from VDD to VBACKUP
I had those initializations in my early projects, but they disappeared at some point.
I have added them back into the current project.
Hopefully that fixes my issues. I will let you know in a couple days.
Thx.