Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

complete bypass the PCS in GIGE Mode

hey there,

The question i can't figure out by reading the manual of the stratix II gx is, wether i can grab receivedata directly at the deserializer of the PMA. I want to leave out the complete PCS, but I dont't know wether this is possible. :confused: I need that for receiving debugging data.

I hope anyone can help me.

Thanks in advance

david

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    I don't think it is possible.

    Use the alt2gxb in basic mode for such purpose.

    I am curious, isn't it the decoded RX data is much more easier to be debugged? Why would you want to see the 10B code instead of the 8B code? You still able to access the control and data character isn't it?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    Page 1-7 in volume 2 of the Stratix II GX Device Handbook states:

    Receiver Phase Compensation FIFO Buffer

    Each receiver data path has a dedicated phase compensation FIFO buffer

    that decouples phase variations between the FPGA and transceiver clock

    domains. this block is always used and cannot be bypassed.

    This block alone cannot be taken out. The minimum latency before you can get your hands on the received data is 4 clock cycles (depending on the protocol you are using).

    Jake
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    Thanks for the answers guys

    Indeed that wasn't the answer i wanted to hear, but unfortunatelly i worried that would be the only one :)

    That was what i figured out, too.

    Now i try to bypass as much as i can and then we'll see. The thing is, that we've got an own SGMII with our own PCS, so i just needed the pure stream. Seems to be more difficult then we thougt before.

    thanks and regards

    david