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DP83865 - fixed MAC Interface

Grzegorz Slugocki
Prodigy 20 points
Other Parts Discussed in Thread: DP83865

Hi. 

I'm using the DP83865 in the configuration: FPGA - DP83865. I want to set a fixed MAC interface (GMII) regardless of the negotiated speed. How can I do it?

Thanks

Greg

 

 

  • 0
    TI__Mastermind 31600 points

    Greg,

    I am not sure that I understand your question.  Are you asking if the DP83865 can function in 10Base-T, 100Base-TX, and 1000Base-T via the GMII without any additional configuration?  If so, this is part of normal operation.  The GMII will adjust based on the negotiated line speed.  There are some details on the GMII in the DP83865 datasheet.  If this is not the basic point of your question, please let us know what additional information we can provide.

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 20 points

     

    Hi Patrick,

    I asking if the DP83865 can function in 10Base-T, 100Base-TX, and 1000Base-T via the GMII (always). In the datasheet is information:

    "The link speed is determined by Auto-Negotiation, by

    strapping options, or by register writes. Based on the

    speed linked, an appropriate MAC interface is enabled."

    For 10Base-TX and 100Base-Tx MAC interface is MII, but I want use GMII (always use GTX_CLK with a frequency 125 MHz). Is it possible?

    Then I needs only one interface in the FPGA to handle all speed.

    Greg 

     

     

  • 0
    TI__Intellectual 1720 points

    Hi Greg,

    GMII interface is also used for 10/100 communication with the MAC.

    Can you please be more specific to what you refer to when requesting 'Fixed GMII regardless to negotiated speed' ?

    Thanks & Regards,

    Oren

  • 0 in reply to Oren Shalita
    TI__Mastermind 31600 points

    Greg,

    It appears to me that two copies of your original post were on the forum and both were receiving replies.  In order to keep the threads from diverging, I have joined them.  Please use this thread for replies going forward.

    Patrick

  • 0 in reply to Patrick OFarrell
    TI__Mastermind 31600 points

    Greg,

    Just following up to see where you are on this.  There were still some open questions on our side, but it is not clear to me if you have the information that you need to close this out.  Is there further clarification that we can provide?

    Patrick