• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 34 subscribers
  • Views 746 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DP83865 with MII mode

user1004134
Prodigy 85 points
Other Parts Discussed in Thread: DP83865

Hello,

 

Can I configure the DP83865 in 10/100 MII mode only?

If so, could you tell me how to set strap pins?

 

I’m using Intel’s LXT972A Single-Port 10/100 Mbps PHY Transceiver, and this PHY is going to EOL. I’m planning to replace Intel’s PHY with DP83865, because of our firmware driver supports LXT972A and DP83865. I’m planning to use current magnetics(2ch) and MAC MII interface without changing firmware. The MAC is configured using FPGA IP core in my design. I would like to know the followings.

-Can DP83865 works with 10/100M MII interface mode?

-What are the trap settings in case of 10/100M MII mode?

 

Thank you.

Regards,

Nakazawa

  • 0
    TI__Mastermind 23675 points
    Hi Nakazawa,

    We are looking into your question right now.

    Thank you,
    Ross
  • 0 in reply to Ross Pimentel
    TI__Mastermind 31600 points

    Nakazawa,

    MII is just a subset of GMII.  The MAC interface will operate as GMII if the PHY is configured for 1000Base-T.  It will operate as MII if the PHY is configured for 100Base-TX or 10Base-T. 

    To configure the MAC interface for GMII/MII, you just need to pull the RGMII_SEL1 strap low. 

    The DP83865 does not offer a strap configuration setting to advertise only 10/100 during auto-negotiation.  1000Base-T will be advertised for all of the available strap options.  Register access via MDIO/MDC will be required in order to configure the DP83865 to only advertise 10/100 during auto-negotiation. 

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 85 points

    Hello, Patrick and Ross. Thank you for your reply.

     

    Per your comments on this, I understood the DP83865 does not have 10/100M only advertise strap setting. Looking into datasheet, I’m thinking of the below setting will be the one in this case that PHY to get configured into 10/100M mode. (0:Low 1:High)

    H/W settings to PHY:

    RGMII_SEL1:0

    SPEED0:0

    SPEED1:0

    AN_EN:1

     

    Driver initialize access to PHY:

    ANAR, 1KTCR (bit9,8=0), and auto-negotiation related access to advertise 10/100M mode.

     

    What do you think?

    Regards,

    Nakazawa

  • 0 in reply to user1004134
    TI__Mastermind 31600 points

    Nakazawa,

    Your thinking is correct.  I would like to add a few minor comments:

    1. In order to advertise 100Base-TX full-duplex and half-duplex as well as 10Base-T full-duplex and half-duplex, you will want the DUPLEX strap set to 1.  This is the default value for the DUPLEX strap, but I wanted to add it to your list.
    2. To clear advertisement of 1000Base-T full-duplex and half-duplex, you should clear bits 9 and 8 of 1KTCR.  No changes are required for ANAR.  
    3. After updating 1KTCR, you should restart auto-negotiation by setting bit 9 of BMCR.  

    Please let us know if you have any additional questions.

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 85 points

    Thank you, Patrick.

    Regards,

    Nakazawa