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DP83640: DP83640 auto MDIX issue

Expert 4300 points

Replies: 9

Views: 108

Part Number: DP83640

Hi team,

my customer found DP83640 auto MDIX issue, when their board connect to computer, it can work good. when two board connected by switch, it can also work good, but if this two board connect directly(TD to TD, RD to RD), it can not works, but customer found auto MDIX function is already enable by defult, so could you help to share some more comments why this happens?

Thanks very much.

Regards, Sunny

9 Replies

  • Hello Sunny,

    Can you please clarify the issue, you are saying that when connected directly, even with auto-MDIX enabled, there is no link? Is this correct?

    When you mean connected directly, can you explain what the signal path is from DP83640 IC to DP83640 IC? Please provide  block diagram if possible, with pin numbers.

    Is auto-MDIX enabled on both boards?

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    HI Vibhu,

    please see my detail description as below:

    this is customer`s board, they soldering RJ45 to the board, if connect to computer, it can be link good, and if two of this board conect with switch, it also link good.

    but if customer use mother board as below to connect two board:

    and connect blockdiagram is:

    this two board can`t communicate, but it can auto set to 100M rate.

    both of this two dp83640`s 0x19 registor is 0x8023, so auto-mdix is enabled.

    could you help to share some comments why this happens?

    Thanks very much

    Regards, Sunny

  • In reply to Sunny Qin:

    Hello Sunny,

    Is there a link between the two PHYs in this configuration?

    Can you send me read values for these registers from both PHYs:

    0x00, 0x01, 0x10

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    Hello Sunny,

    Do you have the information I requested above?

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    Hi Vibhu,

    we don`t have registor information yet, but has some new progress: when customer use special wire connect board A`s TX to board B`s RX, it still can`t communicate, so it shouldn`t issue of MDIX, customer found that there is signal on TX indeed, but RX never trigle Interrupt, so issue should happen on RX, it board B`s RX connect to TX of Switch of computer, it can receive data, but it can`t receive data if connect to TX of board A.

    Do you have any more suggestion?

    Thanks very much.

    Regards, Sunny

  • In reply to Sunny Qin:

    Hello Sunny,

    I will be able to suggest more steps once I can see the configuration and status from the registers requested. When you say TX and RX, I assume you mean TD and RD correct? The MDIX is for connections on the MDI side not the MII side with RX and TX. Can you confirm?

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    Hello Sunny,

    Do you have any update on this? Please let me know.

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    hi Vibhu,

    as it`s China new year now, so feedback will be about one or two weeks later, i will keep update once customer back to office.

    Thanks very much.

    Regards, Sunny

  • In reply to Sunny Qin:

    Hello Sunny,

    I am closing this thread, please open a new one (ask related question) when you have an update from the customer. 

    Happy Chinese new year!

    Thanks,

    Vibhu

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