Forum Discussion

designEngineer's avatar
designEngineer
Icon for Occasional Contributor rankOccasional Contributor
5 years ago
Solved

LVDS SERDES IP no DPA lock in simulation

Hi, I am trying to simulate an LVDS SERDES IP but don't seem to get DPA lock and with that never any data output. I am simulating with ModelSim Intel FPGA starter edition 2020.3. IP Settings: -...
  • designEngineer's avatar
    designEngineer
    5 years ago

    I figured out what the issue was:

    I used the example design simulation as a comparison and eventually saw that the example locks only after over 8 us. This seems way longer than what the lock time specification in the device datasheet is specifying.

    I then ran my own simulation for that long (before I had only run it up to 4 us as according to the lock time specification that is way more than should be needed) and it does also lock.

    I am posting this in case someone else ever runs into this issue.

    Thanks for the help along the way.

AminT_Intel's avatar
AminT_Intel
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hello,

I will need to clarify your problem statement. Does the DPA lock not available from the beginning or after after 4 us? It seemed like from your problem statement that we should be expecting DPA lock if you are using DPA mode.

Can you please put your specification on your first comment to LVDS SERDES IP and run 'Generate Example Design' and let me know what you found.

Screenshots from your end about your issue will also be helpful for me to assist you.

In the meantime, you can also refer to our LVDS SERDES IP Guide from this link: https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/ug/ug_altera_lvds.pdf

Thank you,

Amin

  • designEngineer's avatar
    designEngineer
    Icon for Occasional Contributor rankOccasional Contributor
    5 years ago

    As stated in my first comment, DPA lock does NOT go high EVER, not at the beginning and still not after 4 us simulation time.

    Have you run the simulation I provided at all? The reason I provided it was so you can re-create the issue on your end and help. You can see the issue described clearly in there.

    I have already reviewed the LVDS SERDES IP Guide and am following the design recommendations.

    Attached is a screenshot of my simulation that shows that non of the serdes channels ever get DPA lock even though the data lines are all constantly toggling.

    If you can PLEASE take a look at the simulation and help me understand why DPA lock never happens I would greatly appreciate it.

    I have also attached the result of running generate example design hoping this helps.

    Thank you!

    • designEngineer's avatar
      designEngineer
      Icon for Occasional Contributor rankOccasional Contributor
      5 years ago

      @AminT_Intel, do you have an estimate when you think you can have an update on this?

      Thanks!

      • AminT_Intel's avatar
        AminT_Intel
        Icon for Regular Contributor rankRegular Contributor
        5 years ago

        Hello,

        I understand your frustration and I appreciate your patience. I have looked on your design and I found that there is no data on your DPA SERDES. I would advise you to follow the step on this video: https://www.youtube.com/watch?v=rvAByFs4G7c and let me know if you still run the same issue.

        Thank you.