“STM32L433RCT freezing (lock-up) problem

[albfurkan]

Hello,

I am experiencing the following issue with the STM32L433RCT microcontroller I am using: when I pull the NRST pin LOW and then release it to HIGH, the microcontroller does not recover from reset. In this case, power cycling the device does not solve the problem either. However, if I disconnect the battery from the circuit and then reapply power, the device starts up normally.

This issue occurs mostly during the first boot. After the initial startup is successful, even if I reconnect the battery and pull NRST LOW again, the system does not lock up. I am concerned about what would happen in the field if the device were to freeze and could not recover using a reset.

[TDK]

That chip boots up into the bootloader when flash is empty. Could be what is happening. You will need to do a power cycle after programming the chip to reset the "flash empty" flag. Just toggling NRST will not do it.

Could also be any number of other issues. Is BOOT0 held low or set via option bytes?

Attach a debugger to see where the chip is at and why it's not functioning correctly.