PA2 pin goes low on power up for no reason.

[Shadowhunter]

Hello to everyones

In a project where I used the STM32G0B1RTC6 MCU I have the following problem:

The PA2 pin used as uart2 TX sometimes goes low at power on and stays there forever
even if I try to reset the CPU again. If it is configured regularly then it works as it should.

After several tests I noticed that this happens only in some cases where for a reason that I won't explain, the supply voltage has a rise of the type indicated in the picture i attach.

The strange thing is that the rest of the mcu works, the program runs regularly and the uart2 -rx receives data even though the uart2-tx is stuck low.

Not even a reset can solve the situation, it is necessary to turn off and restart to solve the problem.

I am interested in understanding the nature of the problem. I have solved the problem for the moment by moving the Uart2-tx functionality to pin PD5 but in this way I lose the possibility of booting the MCU through uart2 (PA2/PA3).

I thank anyone who can help me

[Imen.D · Accepted solution]

Hello @Shadowhunter ,

Check if this issue with PA2 is related to a known problem documented in the errata for the STM32G0 series, which can cause the pin to be stuck in a low state, as you have observed.

[Shadowhunter]

Thank very much i resolved the problem based on the 2.2.11 in "Errata sheet" using the software workaround.
In my case it worked.