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DP83822I: DP83848 can't link issue

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Replies: 5

Views: 116

Part Number: DP83822I

Hello  Team

My customer is using DP83822 and now have a problem.

When two phy have the same adress, use “straight cable to connect the two phy. When the two phys reset time interval less than 8ms. There will be connection problem. LED0 is off. When use crossover cable will not have this issue. So could you help look about it and give some comment? thanks.

  • Hello Xiao,

    I suspect the issue is with whether the auto-MDIX resolution is enabled. "The DP83822 can determine if a “straight” or “crossover” cable is used to connect to the Link Partner. It can automatically re-assign channel A and B to establish link with the Link Partner."

    Please refer to section 8.4.7 of the datasheet and configure the PHY to have Auto-MDIX enabled using a bootstrap or register configuration. If this is already done, please let me know.

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    Hello Vibhu

    Yes. it is already done.

    When two same address PHY use straight cable  can't link, use this cable to connect a different address PHY, the link will success. Then connect to the same address PHY, the link will success. It seems to have some things to do with the address. 

  • In reply to Xiao Zhu2:

    Hello,

    Can you please provide the following details on your test:

    1) Are you powering up / resetting the devices at the same time? You mentioned 8 ms, does the issue go away when powering up at a bigger time interval?

    2) What is the cable length that you are using?

    3) Please provide the register values for 0x0000, 0x0004, 0x0019, 0x0467 and 0x0468.

    Thanks,

    Vibhu

  • In reply to Vibhu Vanjari:

    Hello Vibhu

    ) Are you powering up / resetting the devices at the same time? You mentioned 8 ms, does the issue go away when powering up at a bigger time interval?

    >>No, Dp83822 connect to AMIC110. When power up the AMIC110 will have almost 300ms to initialization. After this, AMIC110 put reset_N to low for 10ms, then Initialize the PHY DP83822. 

    Yes, when set the reset time interval than 8.8ms, will not have is issues.

    2) What is the cable length that you are using?

    >>both short cable(15cm) and long cable(100m) have tested. Only use straight cable have this issue(when The two PHY have the same address). When the two PHY have different address, not have this issue. We also do another test, when this issue happened,  connect a DP83822 which have different address, they will connect. then connect back to the same address phy. it will also link success.

    3) Please provide the register values for 0x0000, 0x0004, 0x0019, 0x0467 and 0x0468.

    >> i will provide them later.

  • In reply to Xiao Zhu2:

    Hello Xiao,

    I am going to close this thread as the conversation was taken offline.

    Thanks,

    Vibhu