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DP83848K: Unable to establish connection, no ping

Part Number: DP83848K

Hi team,

Here's an issue from the customer may need your help:

The customer use the GD32F450 with DP83848K to design the network portion. With RMII mode, the MCU provides a 50MHz clock, the MCU can communicate with the 83848 PHY properly and read the PHY value. The initialization is complete and the green and yellow lights on the network interface are on. While TCP/UDP connections to the host cannot be established and pings cannot be made. What could be the possible reason?

Could you help check this case? Thanks.

Best Regards,

Cherry

  • Hi Cherry,

    By green and yellow lights, do you mean that the PHYs are linked-up?

    If the PHYs are linked-up, then we should check the MAC interface connections next.

    To validate that the MAC interface connections are good, I suggest doing the following from the processor

    1. Enable xMII loopback on DP83848K by programming bit 14 of register 0x0
    2. Start data transfer (either know packets or PRBS pattern) from the processor/host.
    3. Check if the data transmitted is same as the data received.

    Separately, I also recommend checking RMII transmit timing and RMII receive timing requirements in 'AC Timing Requirements' section of the datasheet.

    --
    Regards,
    Gokul.

  • Hi Gokul,

    Thanks for your support!

    By green and yellow lights, do you mean that the PHYs are linked-up?

    Yes, PHYs can be linked-up and can read/write register values normally.

    Also because the customer is using RMII mode, does the loopback test also support RMII mode? MII mode is supported according to the datasheet. 

    Thanks and Regards,

    Cherry

  • Hi Cherry,

    Loopback function is supported in RMII mode too.

    --
    Regards,
    Gokul.