Optimize STM32MP135F RTC power consumption

aloiseau · ‎2025-10-02

I have a STM32MP135F with a 3V3 47mF supercap on its VBAT line.

Internal RTC appears to work fine with power outages up to 3 or 4 hours, whereas I hoped one day.

I see in datasheet "Table 27. Current consumption in Vbat mode" that I can tweak VBAT powered sub-components to reduce this set (Backup SRAM, ) and increase RTC backup duration, but I fail to find those settings. Does anyone have it in mind?

I am using Yocto and OpenSTLinux on a board derived from DK2.

Regards

PatrickF · ‎2025-10-02

Hi @aloiseau

I think there is no DTS control for this. It is probably hardly coded inside TF-A or opTEE.
Look for PWR_CR2.BREN bit.

Regards

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