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Visitor II
April 12, 2025
Question

STM32L432KC Nucleo GPIOA resets to 0xABFF FFEF instead of 0xABFF FFFF

STM32L432KC Nucleo GPIOA resets to 0xABFF FFEF instead of 0xABFF FFFF

I can't write 0 to $4800 0000 [GPIOA_MODER]

Ports B and C behave as expected: the correct reset values and it is possible to write 0x0000 0000 to B and C.

How can I resolve this?

Or has GPIOA died?

Firmware version: V2J45M31

ST-LINK/V2-1

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2 replies

Amel NASRI
ST Technical Moderator
April 23, 2025

Hi @Karel ,

It looks like PA2 is configured as alternate function in your case.

Can you try the following:

  • Use STM32CubeProgrammer to read GPIOA_MODER register 
  • Perform a mass erase it remains the same
  • Try an ST-Link firmware upgrade if needed.

-Amel

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KnarfB
Super User
April 23, 2025

works for me in VS code and CubeProgrammer. Same Firmware version.

KnarfB_0-1745420866159.png

bare metal assembly to switch the GPIO clock(s) on, nothing else:

_start:
 ldr r0, =0x40021000
 movs r1, #3
 str r1, [r0, #0x4C]

KnarfB