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DP83848IVVX Transmit operation is not working

Basil Alias
Prodigy 90 points

SIr,

 I have made a PCB in which Spartan 6 FPGA will act as a MAC controller and DP93848 Phy is used for Communicating with PC. When I am sending packet from PC to PHY, I am able to receive those packets in FPGA side. But If I am trying to send one packet to PC, its not happening, ie. other side it is not getting received. I am using Forced 100Mbps mose of operation.

For debugging this issue, I connected another similar board using ethernet. I sent one packet from first Board to second board and monitored the RX_DV line in second board.  I have noticed somany transitions in RX_DV line of second board during packet interval.

What may be the reason for this? Please help me in debugging this issue. The circuit is made as per the referance board. TXD[3:0] and TX_EN signal is monitored for timing and undershoot/ overshoot characteristics. There is no issue in waveform charecteristics/timing.

  • 0
    TI__Mastermind 31600 points

    You mention that you can see RX_DV transitions when you connect two boards together and transmit packets.  Are you also able to receive packets in the FPGA on both sides? 

    When connecting between the FPGA board and the PC, what is the link configuration of the PC?  Is it also forced to 100Mbps or is it using Auto-Negotiation to achieve the link?

    Patrick

  • 0 in reply to Patrick OFarrell
    Prodigy 90 points

    No, I am not able to receive the packet. In ideal case RX_DV wave should be 40usec in length for the packet size I am sending,. But with in this 40 usec so many high to low transitions are coming. So FPGA is treating it as an Invalid packet.

    Since I configured DP83848 to 100Mbps forced mode, PC is working at 100Mbps Mode