An issue with the LWIP UDP RX buffer (STM32H753)

[rLand.21]

Hello, community.

So, we are using STM32F753 and activated the LWIP library from the CubeMx.

We use a UDP socket to send strings (used as commands for our own made CLI protocol).

When reading the Rx buffer in the STM, we see that the strings are sometimes received wrong.

For example, we send the following strings over the UDP (the content itself is not important):

"ver 4d" - Received correctly in the Rx buffer

"pwmgen 100 ef" - Received as "pwer" (some kind of a mix with the previous packet)

This mix causes misreading of the string and therefore the CLI protocol not working.

We hope to find some direction to the solution.

If any more details are needed, I'll be happy to provide them.

Thanks,

Raz

[Pavel A.]

Is D cache enabled? Do you flush & invalidate it properly? Search this forum for related threads.

[rLand.21]

Hi Pavel,

Can you elaborate on the D cache thing? where do I enable it and what does it do?

Thanks!

[Pavel A.]

Your reply indicates that you are new to STM32F7 or Cortex-M7​ generally. ST has a Programming Manual for their Cortex-M7 family, there you can find this information.

See also this document, it applies to STM32F7 too.

[KDJEM.1]

Hello @rLand.2​  and welcome to the Community :),

Please follow this article "Ethernet not working on STM32H7x3", it may resolve your problem.

Also, I advise you to take a look at this FAQ: How to create project for STM32H7 with Ethernet and LwIP stack working. This FAQ may help you to configure your project in STM32CubeMX .

I hope this help you!

Kaouthar

[rLand.21]

Ok, it seems the address configurations we have set were wrong and it looks better now in a demo.

We are now running the full application with the fix to fully test it and hopefully resolve this ticket :)

Thank you so much!

[rLand.21]

Thank you for the help guys!

KDJEM.1 has brought us the solution.

Really appreciated!

[KDJEM.1]

Hi @rLand.2​ ,

Glad to know that the issue is already fixed :).

Thank you for your contribution in STCommunity.

Kaouthar

[Piranha]

> to fully test it

Regardless of the results the HAL/Cube is an unreliable broken bloatware anyway...

https://community.st.com/s/question/0D50X0000BOtfhnSQB/how-to-make-ethernet-and-lwip-working-on-stm32