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DP83867IR: About PHYCR

Part Number: DP83867IR

Hi team,

  I have a question about PHYCR.
  According to page 67 on the datasheet(SNLS484E), bit[6:5] in PHYCR is
  listed as RO.
  I understand those bits are RW.
  Is my understanding wrong?

Sincerely,
Tsuyoshi Tokumoto

  • Hi Tsuyoshi-san,

    Your observation is correct. We have noted down and will fix in the next revision of datasheet.

    Regards,
    Geet
  • Hi Geet-san,

     Thank you very much for your prompt reply.

     Please let me ask you two additional questions.

     Q1)Can the DP83867IRPAPR be configured to 10Mbps(fixed) or 100Mbps(fixed) with
        Disable Auto-Negotiation by using Strap pins?

     Q2)If the device set to the following values by the Strap pins is
             turned on,will the port speed be set 1000Mbps?
                      AGEN_SEL[1:0]=b'11
                      Autoneg Disable=b'1


    Thank you and best regards,
    Tsuyoshi Tokumoto

  • Hi Tokumoto-san,

    Q1:  ANEG_SEL[0:1] = 11 shall help force the link to 10/100M speed. 

    Q2: For 1000M, ANEG_SEL[0:1]  : 01.

    Regards,
    Geet

  • Hi Geet-san,

     Thank you very much for your prompt reply.
     Please let me ask you two basic questions.

     I am being asked from my customer about the port speed
     when Auto-Negotiation function is disabled through the straps.

     I found out a following post on E2E.

    e2e.ti.com/.../548482

     According to the above post,I understand that the PHY cannot be forced
     into any speed through straps and the speed select straps are used for controlling
     auto-negotiation advertisement.


     From the above,

    Q1) I think that the port speed is configured to 1Gbps immediately after the power-on,
      because the default values of bit6 and bit13 of BMCR are set to b'10.
      Is my understanding correct?

    Q2) If a user want to fix the port speed,the user will have to write the configuration
      values directly to bit6,13 of BMCR through the MDIO/MDC.
      Then, the user will have to perform the global-software-restart(setting bit 14 of register
      CTRL to 1).
      Is my understanding correct?
      In addition, will there be anything that the user should be careful of?


    Thank you and best regards,
    Tsuyoshi Tokumoto

  • Hi Geet-san,

     I am still expecting your response regarding my questions.

    Thank you and best regards,
    Tsuyoshi Tokumoto

  • Hi Tokumoto-san,

    If I interpreted your use-case correctly, you want to use force mode ( Auto-Neg disable) and use 100M speed. If yes, then MDIO programming will be needed to select specific speed. If you want to limit the Auto-Neg to lower speed 100M, that's something feasible using straps.


    Regards,
    Geet
  • Hi Geet-san,

      Thank you for your reply and I apologize for the delay
      in replying to you.

      My questions have been almost cleared up, but please let me reconfirm
      the following question.

      When my customer wants to use force mode(Auto-Neg disable)
      and use 100M speed, performing the global-software-restart(setting bit 14 of register
      CTRL to 1) is needed after writing "01" to bit6,13 of BMCR through the MDIO/MDC.

      Is my understanding correct?

    Thank you and best regards,
    Tsuyoshi Tokumoto

  • Hi Tokumoto-san,

    Yes, soft reset is needed after configuring the Auto-Neg disable.

    Regards,
    Geet
  • Hi Geet-san,

      Thank you very much for your reply.

      Which is correct, Software restart or Software reset?


    Thank you and best regards,
    Tsuyoshi Tokumoto

  • Hi Tokumoto-san,

    You can do a soft restart/reset by setting register 0x1F to 0x4000.
  • Hi Pimentel-san,

     Thank you very much for your reply.

     My questions have been cleared up!


    Thank you and best regards,
    Tsuyoshi Tokumoto