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Original question:

DP83867CS: Can SGMII polarity be reversed?

DP83867CS: follow up to SGMII polarity reversal question...

Bob C
Intellectual 615 points

Part Number: DP83867CS
Other Parts Discussed in Thread: DP83TC811S-Q1,

Hi Geet,

Thank you for the information about writing register 0x01D5 to reverse the SGMII polarity. 

I was just testing it.  I found that it didn't work until I issued a PCS reset by writing a 0x8000 to address 0x1000. 

Can you please clarify some things about the DP83867 & its datasheet?  

Did I do the right thing in asserting PCS_RESET to enable the SGMII polarity reversal?  If I should follow a specific initialization sequence to properly invert the SGMII polarity, then please specify it. 

When I set the inversion bits, I wrote a 0x3 to register 0x01d5 rather than setting each bit separately.  Is this OK? 

Page 42 of the March 2017 datasheet states MMD3 register is at 0x1000.  Table 103 on page 91 states the register is at 0x0000, which doesn't make sense to me unless it's at a different MMD device address (other than 0x1f).  Is this register aliased, or is the address in table 103 a typo? 

Table 103 refers to both MMD3 and MMD7.   The datasheet doesn't go into detail on these MMDs / registers.  Can I find further information on MMD3 & MMD7 elsewhere? 

Thank  you again for your help.

Bob

  • 0
    TI__Mastermind 23675 points

    Hi Bob,

    Please do a bitwise operation in register 0x01D5.
    You can use register 0x1F and set it to 0x4000 to implement a soft restart.
    Another option is to set bit[15] in register 0x0.
    It is required to do a restart/reset so that the PHY implements the change.
    Whenever changing register setting you should do a restart/reset.

    There is a mistake in the DS. Page 42 should say 0x0 and not 0x1000.

    MMD tells you what page you are accessing.
    For TI PHYs, more register are located in MMD1F.
    However, there are some register located on different pages.
    Please see the DP83TC811S-Q1 datasheet for a good example of how MMD is defined. www.ti.com/.../dp83tc811s-q1.pdf
    Page #43 in the DP83TC811S-Q1 datasheet shows examples of using MMDs other than 0x1F.

  • 0 in reply to Ross Pimentel
    Intellectual 615 points

    Hi Ross,

    Thank you for the reply.

    You are confirming what I had suspected that MMD3 and MMD7 are at pages 3 and 7 (DEVAD=3 or DEVAD=7 instead of 0x41).  

    Neither MMD3 nor MMD7 are defined in the DP83867CS or  DP83TC811S datasheets.  Can I find these definitions elsewhere? 

    Please give me a couple of days to try out these recommendations, and I'll reply back / close out this thread.

    Bob

  • 0 in reply to Bob C
    TI__Mastermind 23675 points
    MMD3 and MMD7 are not in the DP83TC811S-Q1 but it has MMD1, which helps show you how to use an MMD other than 0x1F.
    I am not sure what you are looking for as far as 'definitions'. MMDs can be found in the IEEE specs as well.
    MMDs give you an expansion to the register field.
  • 0 in reply to Ross Pimentel
    Intellectual 615 points

    Hi Ross,

    I was just asking if there is additional information from TI on the DP83867CS registers defined in MMD3 and MMD7 or elsewhere (e.g., register 0x01d5). 

    I realize that Table 45-1 in section 4 of 802.3 calls out MMD3 and MMD7 for PCS and auto negotiation respectively.  

    Thanks again,

    Bob

  • 0 in reply to Bob C
    TI__Mastermind 23675 points
    Hi Bob,

    I am not sure why MMD7 is shown in the DP83867CS datasheet. This is odd.
    I will look into getting this resolved.
    The only register outside MMD1F is the PCS control register (MMD1, register 0x0).
    Thank you for the feedback.
  • 0 in reply to Ross Pimentel
    Intellectual 615 points

    Hi Ross,

    Do you have any further information on the MMD7 register space being referenced in the DP83867CS datasheet? 

    Thank you,

    Bob

  • 0 in reply to Bob C
    TI__Mastermind 23675 points
    MMD7 addition is a mistake.
    We will get this resolved and have it removed.