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DP83TC812S-Q1: SGMII Interface not coming up

Priyanka Nanda
Prodigy 50 points

Part Number: DP83TC812S-Q1

DP83TC812-S PHY is connected to a switch via the SGMII interface. Autoneg has been turned off on the Cu media side and on the SGMII interface. Speed/Duplex has been set as 100Mbps/Full. We see the SGMII link status is up, but no traffic is flowing through the link. Happy to share more details if needed.

  • 0
    TI__Mastermind 42138 points

    Hi Priyanka,

    • Is it correct that data is not flowing in either direction for the link?
    • Can you share what your configuration sequence on the PHY is?
    • Can you check the packet counter registers 0x639-0x63E?  These may help indicate if there is a unidirectional or bidirectional errors.

    Thanks,

    Drew

  • 0 in reply to Drew Miller1
    Prodigy 50 points

    1. In our test setup, we are sending traffic from the DP83TC812 PHY towards Switch. We see FCS errors increment on the switch side. 

    2. We have not send any packets from the switch towards the PHY side yet, because of some limitation.

    3. On the PHY side, we see TX packets increment. Our main goal is to send packets from the PHY towards the switch first.

    4. On startup, the driver initialize and configure the switch, and then writes a predefined set of register values to configure the PHY for the desired operating mode. 

    Register values:

    1. SGMII Mode enabled

    2. Forcing Polarity

    3. Master mode enabled

    4. Autoneg disabled on both PHY and SGMII

    5. Setting 100Mbps, Full Duplex