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DP83867IS: Register 0x01D5 for troubleshooting

Atsushi Takahashi
Expert 1415 points
Part Number: DP83867IS

Tool/software:

Hi Team,

We are having communication problems with the customer system using DP83867IS, and are using the following troubleshooting guide to investigate the cause.
Then, I have a question about section 3.4.
https://www.ti.com/lit/an/snla246c/snla246c.pdf

1) Does it suggest doing steps 1 -> 2 -> 3 -> 4 in that order? Or are these operations independent?

2) Regarding step 4, is the following statement correct?
"Write register 0x01D5 = F508 to change DP83867PHY from low power mode to normal operational mode."
According to the datasheet, I cannot read "low power mode" and "normal operational mode" from register 0x01D5. It seems to be a different register.

Best Regards,

DP83867IS_Register 0x01D5.pdf

  • 0
    TI__Mastermind 25955 points

    Hi Atsushi-san,

    Thank you for going over the troubleshooting guide

    • Customer is seeing unstable link or no link at all with DP83867?
    • If customer see no link, we recommend customer go in order on the troubleshooting guide
    • 0x1D5 = F508 will increase the peak to peak amplitude on the MDI lines but increase power consumption of DP83867.

    --

    Regards,

    Hillman Lin

  • 0 in reply to Hillman Lin
    Expert 1415 points

    Hi Hillman-san,

    Thank you for your reply.

    Communication is no problem after start-up.
    The link partner must be rebooted once a day, and communication problems occur 1 in 200 reboots.
    When there is a communication problem, there is no ping response from the link partner.
    At this time, the link LED remains lit.

    I would like to know more about the solution of step 4 in section 3.4.

    1) The default for register 0x01D5 is F500, and the only difference with the written value F508 is that Bit[3]=0 or 1 . Is the purpose of this solution to rewrite this bit? Does this increase the peak-to-peak amplitude of the MDI line?

    2) Am I correct in understanding that the default F500 is low power mode (low amplitude of the MDI line) and F508 is normal operating mode (high amplitude of the MDI line)? If yes, I can understand the DP83867 is in steady state in low power mode. 

  • +1 in reply to Atsushi Takahashi
    TI__Mastermind 25955 points

    Hi Atsushi-san,

    1) Yes, this bit will increase the peak to peak amplitude of the MDI lines

    2) Yes, your understanding is correct. The default value for DP83867 is in low power mode (low amplitude of the MDI lines)

    --

    Regards,

    Hillman Lin