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DP83867IS: Auto Negotiation failed sometimes

John11513
Expert 5720 points
Part Number: DP83867IS

Hi Experts:

My customer reported an issue with DP83867: sometimes Auto Negotiation failed and the receiver clock frequency is measured at 2.5MHz or 25MHz. 

In this condition they tried MII loopback test, failed.

This problem may disappeared if they plug off-and-on cable may times.

They read the internal register in fault condition, the content of register is:

They found a significant difference in register 0x000A between good and fault condition: the content is 0x3800 in good condition and 0x0800 in wrong condition.

What is the possible rootcause of this issue?

Thank you!

John

  • 0
    TI__Genius 16030 points

    John,

    Register 0x000A value of x0800 shows that receiver status of far end and local receive is not ok yet. Can you please check if writting register 0x001F = x8000 helps (resets the PHY)? Are they using short cable (<1m) or a long cable? Can they do the test with a different cable (if short cable is being used then may be a little longer cable) to understand the dependency on the cable.

    --

    Regards,

    Vikram