I have an STM32L0 project that operates from a CR2032 coin cell battery. The board operates fine most of the time but there have been a few occassions where the power cuts out after a couple of hours or so and then the board will fail to boot up with either a new battery or even through an ST-Link connected to a PC for USB power - it also thus fails trying to recognise the MCU. Eventually, powering it from a benchtop power supply connected to the retainer or even the 3.3V rail turns it back on fine again and then it can operate from the original battery for literally days regardless if I temporarily remove it. The bench power supply is still set at 3V and 3/400mA - which doesn't make sense to me because the ST-Link provides more than that I thought - this is still more than a coin battery though.
I've attached the MCU and power related schematic. The boost converter is for an OLED that's connected via the i2C pins. OLED is on a standard breakout board so nothing custom.
From a firmware perspective it doesn't use any of the low power modes yet, the clock uses LSE. I do have an RTC enabled but I don't do anything with back-up registers, I also don't change anything in Flash memory in the firmware so that ruled out any flash corruption type issues - in any case even if there was corrupted flash I don't think that explains why it starts working after enough power is applied. Also the issue isn't time related, it's not like it starts working after a period of time so it's not a thermal and cooling type of issue, it's literally whenever you give it enough power it will work as normal again. I've attached a stripped down version of main.c, the other functions I've taken out don't do anything special other than math stuff and turning timers on and off plus some writing out to the OLED if a button is pressed.
Maybe it's something/s silly I've missed in the schematic but hoping someone has some ideas! Thanks
