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Original question:

DP83867E: TI solution suggestion

DP83867E: Can any of them also measure the cable length?

Jimmy Lai
Expert 6845 points
Part Number: DP83867E

Dear Team,

Thanks for your support!

All our PHYs support TDR. But TDR featurelist will be more or less the same across PHYs.

=> Can any of them also measure the cable length?

Many Thanks,

Jimmy

  • 0
    TI__Mastermind 28030 points

    Hi Jimmy,

    We're looking into your question and will get back to you by Wednesday.

    Thanks,

    Lucas

    All information in this correspondence and in any related correspondence is provided “as is” and “with all faults”, and it is subject to TI’s Important Notice (http://www.ti.com/corp/docs/legal/important-notice.shtml).

  • 0 in reply to Lucas Wolter
    TI__Mastermind 28030 points

    Hi Jimmy,

    Once you've run the TDR steps, you can follow the below example to convert the register values to cable length for DP83867.

    Assume that after executing the TDR script, location for Peak 0 on Channel A (Register
    0x190[7:0]) is recorded as 0x40. The decimal value is 64.
    Peak location = (64 * 0.862) – 17
    = 55.16 -17
    = 38.16 meters
    The location of the peak is approximately 38.16 meters from the PHY. This can be used to
    detect break in cable, impedance discontinuity or cable length. For measuring cable length,
    leave the other side of the cable unconnected and follow the procedure.

    Please let me know if you have any other questions, otherwise I'll close the thread.

    Thanks,

    Lucas

    All information in this correspondence and in any related correspondence is provided “as is” and “with all faults”, and it is subject to TI’s Important Notice (http://www.ti.com/corp/docs/legal/important-notice.shtml).