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Altera_Forum's avatar
Altera_Forum
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16 years ago

Problem in sending a packet using ethernet MAC

Hi ...:)

I integrated a custom MAC into my design. I transmitted a packet which I could see in the SignalTapII analyzer. But when I connected my NEEK board to another PC using crossover ethernet cable and when I ran Wireshark in that PC, I couldn't see any of the transmitted packets. Where could have been the problem...?

And one of the LEDs(orange indicating Link/Activity) is off for the moment when I send the packet and after that it is ON again. Please help me regarding this problem..

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Is the Phy detecting the cable and negotiating the speed? The Interniche stack should say something about that.

    Did you check the clocks sent to the Phy and did you add the timing constraints? They are especially important in gigabit mode.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Hi,

    I could able to detect the PHY Cable and Speed 100Mbps.With my own Stack, its initiating a trasmission of a Packet, I could able to view the Txen ,Txdata[3:0] signals in Signal Tap II Analyzer, But I cant able to capture the data in Wireshark .

    I havent set any timing constraints ,If you feel there are some timing Problem what are the timing constraints to be set ?
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Every synchronous interface should be constrained for setup and hold, according to the PHY datasheet (or MII specification). But if you are at 100Mbit/s the interface is at 25MHz only, and it *may* work without constraints. Still it is good practise to do it ;)

    On some PC's the network hardware/driver automatically discards badly formed packets. You could try and see if you can disable those functions in the driver, or try with another PC (an old one, if possible ;) )