RTC is not incremented with a voltage Vbat below 0.6V

[Mickael_Biyotee]

Hello,
we use an STM32WB55 with an RTC backup via a super capa.
when the Vbat voltage drops below 0.6V, the RTC registers are no longer incremented.
if the board reboots at this point, we have a datetime offset.
is it possible to detect this problem when the STM32WB55 starts up?

thank you in advance for your help

[TDK]

Measure the VBAT voltage on startup with the ADC and, if it was below the threshold, require that the RTC be reset.

[SofLit · Accepted solution]

Hello,

You can use ADC in watchdog mode:

[Mickael_Biyotee]

Thanks for your answers.
I added reading VBat at CPU startup and resetting the RTC if necessary and it works very well.