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albertolr98's avatar
albertolr98
Icon for New Contributor rankNew Contributor
4 years ago
Solved

Rx word allign in high speed transceiver.

Hi, I'm trying to implement a standar PCS protocol that involves 8B/10B enconding and decoding 16bits.

To try the protocol i have made a physical loopback with some sma cables. I have confirmed that transmitter side works cause I have receive the info in another board without a problem.

The problem lies in the receiver side. When I try to read the loopback signal, no matter what I tried I don't get it to allign the info properlly.

In the receiver word allign pattern i have tried several possibilities, like setting rx word allign mode to synchronous state machine, rx word allignment length: 20 and rx word allignment pattern to 0xA0E83 (which is the 20b equivalent of 0xBCBC or I think so) while sending a constant K28.5 (0xBCBC).

I have no clue what is happening or if I'm understanding something wrong.

Thank you in advance,

Alberto López.

  • CheepinC_altera's avatar
    CheepinC_altera
    4 years ago

    Hi,


    As I understand it, you have some inquiries related to the word alignment of the XCVR RX. Since it was not mentioned which specific Quartus version, FPGA device and IP used, I am assuming that you are uisng a Native PHY IP. Generally in the Native PHY IP, you should see some presets ie GIGE. You can apply the GIGE preset and check on the word alignment pattern used. You may need only 10bits word alignment pattern. You may try to get the simple GIGE preset running then slowly customize from there.


    Please let me know if there is any concern. Thank you.


3 Replies

  • CheepinC_altera's avatar
    CheepinC_altera
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    Hi,


    As I understand it, you have some inquiries related to the word alignment of the XCVR RX. Since it was not mentioned which specific Quartus version, FPGA device and IP used, I am assuming that you are uisng a Native PHY IP. Generally in the Native PHY IP, you should see some presets ie GIGE. You can apply the GIGE preset and check on the word alignment pattern used. You may need only 10bits word alignment pattern. You may try to get the simple GIGE preset running then slowly customize from there.


    Please let me know if there is any concern. Thank you.


  • albertolr98's avatar
    albertolr98
    Icon for New Contributor rankNew Contributor
    4 years ago

    Hi,

    The problem as you mention was that I was trying a 20bit pattern when only a 10bit pattern was needed.

    Thank you,

    Alberto.

  • CheepinC_altera's avatar
    CheepinC_altera
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    Hi,


    Thanks for your update. Glad to hear that you have managed to resolve the problem.


    I believe the initial inquiry has been addressed. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.