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Altera_Forum's avatar
Altera_Forum
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15 years ago

Can someone give a hint of what the problem is? (CycloneIV, PCIe, GigE MAC)

I'm trying to implement GigE and PCIe protocol on CycloneIV starter board.

I presume that I'm allowed to use one channel of GXB for PCIe and the other for GigEMAC.

The fitter gives me these following errors:

http://www.alteraforum.com/forum/attachment.php?attachmentid=2766&stc=1&d=1279278041

The document of GXB does not mention any information on how those PLLs are shared/constained and I'm quite desperately clueless now.

Thanks very much,

Jeff

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    I get this if I use the same refclk for PCIe and GigE. If I use the 125MHz clock (E7) for GigE and the 100MHz clock (J6) for PCIe, my project builds, but my design still doesn't work. Did you get anywhere on this? My PCIe works, but GigE fails to complete autonegotiation and never seems to get any data to the GXB.

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    Did you try the BTS examples? They have two separate examples, one that uses GigE and another that uses PCIe.

    You would have to use two separate clocks for GigE and PCIe anyway, since GigE would use an on-board reference, whereas PCIe uses the 100MHz PCIe clock.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    Yep, got both examples working separately, and even got a from scratch project working with GigE built from megawizard. The problem only seems to be trying both at the same time. I do use both refclks as you described. I'm suspicious of some issue related to transceivers sharing a quad block, perhaps I need to do some special reconfig magic to make them work together? Not really sure. Been banging my head on the wall for a while now with this.

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    --- Quote Start ---

    Yep, got both examples working separately, and even got a from scratch project working with GigE built from megawizard.

    --- Quote End ---

    Ok, that's a good start.

    --- Quote Start ---

    The problem only seems to be trying both at the same time. I do use both refclks as you described. I'm suspicious of some issue related to transceivers sharing a quad block, perhaps I need to do some special reconfig magic to make them work together? Not really sure. Been banging my head on the wall for a while now with this.

    --- Quote End ---

    Hmm, I'm not sure either. The transceivers are in the same block, so I think you need to use a common altgx_reconfig, but I'm not sure how that ties into two separate instantiations of transceiver blocks ... I've never had a reason to try.

    File a Service Request with Altera. I've filed a couple recently and they have responded pretty rapidly.

    Cheers,

    Dave