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vlacr.11
Associate II
January 31, 2022
Question

Ethernet on ST STM32H747I Discovery board

Hello, I am working on the ST STM32H747I Discovery and I have a question regarding Ethernet. According to the ST documentation (https://www.st.com/resource/en/user_manual/dm00504240.pdf), some hardware modification is mandatory to manage Ethernet. However, I can perform some Ethernet communication on my ST STM32H747I Discovery board without any modification (works like a charm). Any clue about that ?

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3 replies

ST Employee
February 1, 2022

Hello @vlacr.1​ 

I am not sure but i would say that it depends one how you are initializing the ethernet. which code are you using for that ?

Serial Management Interface, MDIO and MDC Pins are not mandatory. I found that for applications not using the MDIO tie both MDIO and MDC to VDD that is why we talk use the term of managed and unmanaged Phys. That could be the explanation...

BR,

Bruno

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vlacr.11
vlacr.11Author
Associate II
February 8, 2022

Hello @Bruno_ST​ ,

Thanks for your answer. We use Zephyr RTOS with the STM32_HAL.

I am glad to hear there could be an explanation :) .

Best Regards,

Vincent

Piranha
Principal III
February 10, 2022

Just take a note that MODE[2:0] pin straps configure the PHY into all-capable auto-negotiation mode. That means you have to set the MAC to the same configuration as will be the result of the auto-negotiation. That said, the typical result will be a 100 Mbps full-duplex mode.