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Visitor II
April 18, 2025
Question

STM32H747I MDIO - can it goes until 32bit

  • April 18, 2025
  • 2 replies
  • 425 views

I am using STM32H747-DISCO board for development, and I try to access for MDIOs connectivity of the STM32H747, I found a document describe about MDIO:
STM32H7-Peripheral-Management data Input Output slave interface (MDIOS)
From the document it describes like the STM32H7 MDIO can go up to 16bits, can it go beyond that and modify it to read/write 32bit data?

If this model cannot support 32bit MDIO, does any other STM32 IC support 32bit MDIO?

This topic has been closed for replies.

2 replies

Billy OWEN
ST Employee
April 18, 2025

Hi @Khey87 

 

This post has been escalated to the ST Online Support Team for additional assistance.  We'll contact you directly.

 

Regards,

Billy

Feng XIONG
ST Employee
April 23, 2025

Hi,

As discussed, there are two options of the ethernet setup.
1) STM32 MCU works as the slave (containing the ethernet PHY) and there is another master (containing the ethernet MAC) to control the STM32 MCU via the MDIO bus. From STM32 MCU point of view, it's MDIOS (MDIO slave) and what "STM32H7 - MDIOS" online doc covers.
2) STM32 MCU works as the master (MAC) which connects with another slave device (PHY) via MDIO. This MDIO is part of the ethernet interface.

The customer confirms that their setup is the 2nd one. STM32H747 supports MDIO (Clause 22 and Clause 45) master interface for PHY device configuration and management.

Best Regards,

Feng