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STM32H743Z (LQFP144) GPIO not working on PC2_C and PC3_C?

David Viens
Associate II

Moved a design from STM32F745Z to STM32H743Z (rev Y as thats the only thing ever available you know) 

with the help of CubeMX's "List Pinout compatible MCUs" and for the most part that went dandy except when trying to using PortC!

It took me a while to figure this out but PC2 and PC3 (which worked fine in F745Z) did NOT pulse or correctly (or read values) when setting those pin as Digital GPIO on H743Z

Backtracked a bit and noticed changes in the way PC2 (PC2_C) and PC3 (PC3_C) are described from TT_a and Analog only functions to a bunch of things in later revs of the datasheets.

My #1 request for a future build of CubeMX is to be able to quickly show which pins are FT_x and TT_x. THIS IS CRUCIAL FOR SYSTEM DESING and is NOT something that CubeMX knows at ALL.

We need a way to highlight all FT pins, all TT pins, etc. Especially if a pin was FT_x and it changed to TT_x in a subsequent MCU - this is NOT pinout compatible!

But back to my question, is there any way to salvage my boards and make PC2_C/PC3_C output 3.3V Push Pull? (my VCC is 3.3v)

My scope does not show any movement which pulsing PortC on those specific pins, which PC0,PC1,PC4,5,6,7 work just fine fine.

Tried messing with o PC2SO/PC3SO in SYSCFG_PMCR and that didn't change, the bits always read as 1's

Thanks for any info.

12 REPLIES 12
MEdgerton
Senior

Update:

I have PC3_C working at high speed. But not PC2_C (PC2). I cannot see any reason why this is not working now. I believe this to be a low-level ST bug in firmware or something. I built a project from scratch and can show this on the scope just tolling IO pins PC0. PC2, PC3. PC2 does not work at high speed. Nothing other than a scope connected.

Can someone double check this. How do I report a suspected bug to ST?

Mohammed Eshaq
Associate III

I am working on a project, and was trying to use PC2_C as a GPIO_EXTI and just realized that this particular pin doesn't generate interrupt signal, meaning, your ISR will not be called for this particular pin. I had to change the layout and use another pin as a GPIO_EXTI to continue.

I was able though to use it as an GPIO Input but performance was a bit weird.

I believe this is a bug that must be reported to STM; If the pin cannot be used as a GPIO or GPIO EXTI then the CubeMX tool should block/not allow you to select these option for this pin.

We have seen the same problem.

https://community.st.com/s/question/0D53W00000xpDZLSA2/stm32h735v-lqfp100-pc2c-and-pc3c-speed

You are correct, it is a hardware issue.