RTC is not incremented with a voltage Vbat below 0.6V

Mickael_Biyotee · ‎2024-02-02

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

SofLit · ‎2024-02-02

Hello,

You can use ADC in watchdog mode:

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View solution in original post

TDK · ‎2024-02-02

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

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SofLit · ‎2024-02-02

Hello,

You can use ADC in watchdog mode:

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.
PS: Be polite in your reply. Otherwise, it will be reported as inappropriate and you will be permanently blacklisted from my help/support.

Mickael_Biyotee · ‎2024-02-06

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