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DP83TC811EVM MII Interface Connection

Teik Hooi Teoh
Intellectual 655 points

Other Parts Discussed in Thread: DP83TC811EVM, DP83TC811, DP83TC811SEVM

Hi,

I am looking for available platform or evaluation board that can provide MII connection to DP83TC811EVM (which has header connector fo MII, RMII, RGMII interfaces).

Is there anything from TI for that purpose?

If not, is is possible to have the MII interface back-yo-back connection using two sets of DP83TC811EVM?

Please advice. Thanks!

Regards,

Teoh

  • 0
    TI__Expert 7040 points

    Hi Teoh,

    It is not possible for MII to be configured in back-to-back mode. Unfortunately we do not have Ethernet evaluation boards that include a MAC or MC to pair the the DP83TC811.

    Regards,
    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 655 points

    Hi Justin,

    What is the main reason that this is not possible? I did come across back-to-back for RMII and RGMII.

    I am just curious, as the DP83TC811SEVM is designed to have the xMII interface in header connector, should it be meant for interfacing with another device / eval board with MII connection interface?

    If that device / eval board is not within TI, is there any other that can do so?

  • 0 in reply to Teik Hooi Teoh
    TI__Expert 7040 points

    Hi Teoh,

    In MII mode, the PHY provides both TX and RX clock signals to the MAC. This means that that when two PHY's are connected both clock signals are outputs and cannot be configured as an input where one is needed.

    The DP83TC811 EVM can be interfaced with MII MAC through jumper wires. I am not aware of any MAC evaluation modules that breakout the MII pins to connect to. What is driving the need to breakout the DP83TC811 EVM to pins?

    Regards,
    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 655 points

    Hi Justin,

    Thanks for the explanation! Now I understand the reason.

    I think I have a typo: it should be DP83TC811SEVM. This eval board has the xMII interface readily pulled out to a header connector.

    And it needs xMII to be driven by some external system in order for the whole eval board to work.

    That is why I had the idea that it should be built with the need to work with another TI platform/EVB that has the xMII interface to drive this DP83TC811SEVM.

    Just wondering the purpose to have this evaluation board in the first place.

    Anyway I will try to look elsewhere if TI really does not having the matching solution.to drive this board.

    Regards,

    Teoh

  • 0 in reply to Justin Lazaruk
    Intellectual 655 points

    Just some additional thoughts:

    Is there a reverse MII mode for DP83TC811? Where the RX_CLK and TX_CLK can be reversed as inputs.

    It seems that many other PHY IC has this feature.

    But I can't seems to find it on DP83TC811.

    Anyone can help to confirm on this?

    Regards,

    Teoh

  • 0 in reply to Teik Hooi Teoh
    TI__Expert 7040 points

    Hi Teoh,

    The DP83TC811SEVM has the MAC interface pins broken out for that customers can measure timing signals and jumper connections to another MAC, however this is mostly for RMII and RGMII since another PHY with the broken out pins can be connected and work in back to back mode. You are correct, in MII mode that is not readily available. 

    The DP83TC811 cannot reverse the direction of the RX_CLK and TX_CLK to work as an MAC for another MII PHY. 

    Regards,

    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 655 points

    Hi Justin,

    Thanks for the explanation.