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DP83869HM: SGMII_to_RGMII bridge mode link up succeed, but fail to transmission data

Zhengrui Kuang
Prodigy 10 points
Part Number: DP83869HM
Other Parts Discussed in Thread: DP83869,

Hi:

I choose DP83869 to connect SGMII mac with RGMII phy. After pulling up PIN_22 GPIO_1, PIN_36 RX_D3 and PIN_38 RX_CTRL(SGMII_to_RGMII bridge mode), they can link up in 1000M_FULL mode and SGMII mac can receive data from RGMII phy. But RGMII phy cannot  receive data from SGMII mac.

It's even more confusing that if PIN_38 RX_CTRL pull-up is broken the performance of this system is consistent with the above which is supposed to be RGMII_to_SGMII bridge mode.

Because of design error, I cannot get the information of the registers in DP83869HM. I don't know how to find out where the problem lies and wish to get help from you.

Btw, pairs of TXdata and RXdata are between SGMII mac and DP83869HM and I wonder if necessary to make some configurations of RGMII phy through MDIO&MDC interface on the SGMII mac side.

Looking forward to your reply

Thanks

  • 0
    Prodigy 10 points

    And which side should PIN_41 MDIO  and PIN_42 MDC connect to in SGMII_to_RGMII bridge mode, SGMII mac or RGMII phy?

    I highly doubt that I use DP83869HM in wrong way

  • 0 in reply to Zhengrui Kuang
    TI__Mastermind 25048 points

    Hi Zhengrui,

    Please share the schematic so I may verify the DP83869 configuration and pinout (email to e-mayhew@ti.com for private share).

    MDC/MDIO should be connected from the MAC to each PHY for SMI access.

    Thank you,

    Evan

  • 0 in reply to Evan Mayhew
    Prodigy 10 points

    Hi Evan,

    Thank you for your reply!

    I am sorry that I cannot share schematic with you for some reason, but the design is based on the drawing blow.

    The PHY->DP83869->MAC access is working now, and I can capture the signals of RXD3 pin. However, PC connected to PHY cannot received data packet.

    Also, I don't understand what " from the MAC to each PHY for SMI access" means. DP83869/MAC/PHY all have MDIO/MDC pins, but how to connect in SGMII-to-RGMII Bridge? I cannot get it from the picture.

    Thank you,

    Zhengrui

  • 0 in reply to Zhengrui Kuang
    Prodigy 10 points

    Could strap configuration work only without register configuration for functional mode? Now that  PHY->DP83869->MAC access is okay and the signals of TXD[3:0] in DP83869 have already been captured, what is the reason why MAC->DP83869->PHY access doesn't work? I really cannot find out.

  • 0 in reply to Zhengrui Kuang
    TI__Mastermind 25048 points

    Hi Zhengrui,

    SMI connection should look like this for the MAC to access either PHY depending on the PHY address selected:

    Can you clarify which PHY you are having issues with register access, and which you are having data transfer issues with?

    If you have register access with both PHYs, please share register dumps from addresses 0x0 to 0x1F so I may check the PHY configuration.

    Thank you,

    Evan