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

[Karel]

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

[Amel NASRI]

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

[KnarfB]

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

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

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

KnarfB