is there a clock in stm 32 that stays running even if the power is turned off at the MCU?

[LMoha.1]

Hello

for my application I use STM32L0, and I want to retrieve the exact date without changing it every time I turn off the power. Is there a timer that was triggered on the production day of the STM MCU that will allow us to retrieve the date?

[TDK]

No clock can run without power.

The RTC clock can run on minimal power from the VBAT supply, if you configure it correctly.

> Is there a timer that was triggered on the production day of the STM MCU that will allow us to retrieve the date?

No.

[LMoha.1]

Thank you very much

[Tesla DeLorean]

Suspend, running LSE from your supply/battery. Clock the RTC with that.​

[berendi]

The problem is that STM32L0/STM32L1 series don't have VBAT.

[LMoha.1]

@Community member​  . But the problem is that in my application, i turn off /ON the power . is that will Reset the RTC clock?

[Tesla DeLorean]

The electrons are going to need to come from somewhere​

[LMoha.1]

Ok

[Tesla DeLorean]

That's not the physics in my part of the universe.

The L series parts are designed to run off batteries, and that can be used to power the "lower power domain" of the IC which in turn can clock the LSE crystal.

You'd probably want to look at the SNAPHAT/CAPHAT devices for a persistent and self-sustaining clock source

https://www.st.com/content/ccc/resource/sales_and_marketing/promotional_material/brochure/09/c1/e0/e1/dc/64/4e/4e/BRRTC0314_lr.pdf/files/BRRTC0314_lr.pdf/jcr:content/translations/en.BRRTC0314_lr.pdf

[Piranha]

> Is there a timer that was triggered on the production day of the STM MCU that will allow us to retrieve the date?

> Ok i thought that quartz doesn't need power supply

Yes, they have a special perpetuum mobile edition for those, who don't waste their time on physics and other foolish things. Also it has an absolutely perfect accuracy and stability, therefore it always has the correct time.