Boot0 Pin issue in STM32L051

[MSale.1]

What would happen to the microcontroller if during running normally then suddenly the boot_0 pin switched to high?

in my case and due some voltage spike the boot_0 pin state switched to high for very short time nano seconds. most of the time its ok but some times the microcontroller stuck. also the supply voltage has this spike too. from my reading if the boot pin become high then the boot memory switch to system memory. would this cause the microcontroller to totally stuck?

Regards

M.Salem

[TDK]

The BOOT0 pin is sampled immediately after reset only. After that, it can go to other values without affecting the functionality of the chip. Keep in mind the absolute maximum ratings still apply at all times, but if you're within 0-VDD, it's fine.

[MikaelM · Accepted solution]

Hello @MSale.1 ,

please report to reference manual rm0377 (https://www.st.com/resource/en/reference_manual/rm0377-ultralowpower-stm32l0x1-advanced-armbased-32bit-mcus-stmicroelectronics.pdf ) and check paragraph "Boot configuration".

For stm32L051x devices :
"The boot mode configuration is latched on the 2nd rising edge of SYSCLK after reset. It is up
to the user to set nBOOT1 and BOOT0 to select the required boot mode.

The boot mode configuration is also re-sampled when exiting from Standby mode. Consequently the boot mode configuration must not be modified in Standby mode".

If the spike is not in this "category", the spike on boot0 is not sampled.
Please check also the VDD level and be sure that the level is not drops below Vpdr thresholds (1.5V ).
"Power-on reset (POR)/power-down reset (PDR)" paragraph of reference manual.
Best regards.
Mikael