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Fail to configure ETH + LTDC 24bit for STM32H725ZG in CubeMX

Senior II


The STM32H725ZG comes in a 144-pin package and configuring ETH RMII + LTDC 24 bits (RGB888) in parallel would seem realistic. But I have failed even though I have tried to move around pin configurations quite a bit.

A single pin (PA2) seems to be the issue.

Thanks for any hints in case I missed something.

ST Employee

Hello @Lars Sörqvist​,

It would be better to share your configuration, this will help Community user to understand your issue.

Check the LTDC initialization, ETH clock...

Review this article, it may help you: How-to-create-project-for-STM32H7-with-Ethernet-and-LwIP-stack-working

Check the board User Manual, maybe you have a physical connection issue.


When your question is answered, please close this topic by clicking "Accept as Solution".

Thanks Imen,

But so far it is a straightforward issue about pin configuration only, i.e. no user code or LwIP involved.

These are my steps:

  1. I started STM32CubeMX with a new project from scratch for the MPU STM32H725ZG.
  2. I then trried to configure ETH RMII + LTDC RGB88 respectively
  3. There where pin conflicts (no other features/pins configurated)
  4. I tried to move pins around in STM32CubeMX but still ended upp with conflicts

I was just hoping to get an extra pair of eyes on this in case I missed some pin swapping, thats all.

Kind regards

Chief II

Consider using LTDC in 18-bit mode. Take a note that most LCD panels are 18-bit anyway, even those with 24-bit interface.

Thanks, yes that it possible.

However, I have a specific 24-bit screen in mind but I assume I would need to move up to a chip with more pins then?