Resetting RTC domain (workaround for an issue in device errata) would clear time/date data.

wesleywong · ‎2024-07-04

MCU: STM32G070CBT6

According to ES0468 - Rev 5 (STM32G070CB/KB/RB device errata), for issue 2.2.10, the only workaround can be applied is erasing the RTC domain by software during power up.

But this workaround would clear RTC time/date data. Normally, the RTC would keep running as long as VBAT is powered. When VDD is powered, I can keep the RTC time/date data if backup register has specific data. But after appling above workaround, the RTC time/date data and backup register would be erased.

Is there any way to keep the RTC time/date while appling the workaround?

waclawek.jan · ‎2024-07-04

That erratum describes incomplete backup-domain (i.e. VBAT-powered circuitry) *reset*, i.e. a situation, where VBAT is not powered actively from a battery, and drops below 700mV.

If your RTC is running, you have a battery on VBAT which certainly hasn't dropped that low, so the problem can't occur.

JW