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Visitor II
April 12, 2025
Solved

RMII Connection Confusion

  • April 12, 2025
  • 2 replies
  • 536 views

Hello,

This might seem like a silly question but when using the pin names generated by cube IDE for the RMII interface does TXDx connect to TXDx on the PHY or RXDx?

 

On the schematic for the NUCLEO board it seems that the microcontroller pin in named the same as the pin which it connects to on the PHY.

 

Is this the case?

 

Thank you. This really worrying me as I would feel pretty *** if I connect TX to TX and it didn't work.

    This topic has been closed for replies.
    Best answer by TDK

    Yes, TX is connected to TX.

     

    TDK_1-1744461864847.png

    2 replies

    Visitor II
    April 12, 2025

    I should add that:

    I have checked to alternate pin functions table for the part and found the cube IDE label to be conventionally named.

    I have re checked the LAN8742Ai schematic checklist and re confirmed that the table on page 11 does state that the TXDx pin connects the same named pin on the MAC device.

    So the LAN87Ai pin names do not follow the TX RX naming convention because the RMII interface has a net naming standard maybe??

    TDKAnswer
    Super User
    April 12, 2025

    Yes, TX is connected to TX.

     

    TDK_1-1744461864847.png

    Visitor II
    April 13, 2025

    Great, thanks!!