STM32N6 NUCLEO - GPIO fault

[daniel_varga]

Board: NUCLEO-N657X0-Q

Revision: C

Problem: MCU cannot pull PA2 to low, only to about 2.5V. I tried it in push-pull and open drain modes. SB6 has been desoldered to isolate it from the analog attenuation circuit, but it didn't work with it soldered. It doesn't work with the "GPIO_IOToggle" example project either, same behaviour. Pulling the pin up to 3V3 works just fine. PA2 is the pin so far which has caused this issue. Holding the reset button makes the pin go high (3V3), indicating a hardware issue, as far as I know. My best guess is it is somehow pulled up through a pull up resistor, but I haven't found any evidence of it in the documentation.

I attached some documentation which I investigated.

Any help is appreciated, thank you!

[mƎALLEm · Accepted solution]

Hello @daniel_varga and welcome to the community.

@daniel_varga wrote:

Holding the reset button makes the pin go high (3V3), indicating a hardware issue.

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That seems to tell the IO on PA2 is destroyed. Pulling down reset pin puts the IO in Hi-Z.

Do you have another board to test and confirm?

[TDK]

Do other pins have the same issue? If not, likely the board has been damaged. There's nothing special about PA2.

[daniel_varga]

Now that you say it, I can recall a measurement when I might have accidentally given overvoltage to the pin. Since these are not very resilient to that, frying the GPIO is the most plausible explanation...
I don't currently have another board to test this, but this is the only explanation so far.
Thanks for the answer!

[daniel_varga]

Thanks for the answer! Other pins seem fine, I'm fairly certain now that I have fried it accidentally :(