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Altera_Forum's avatar
Altera_Forum
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15 years ago

LVDS Tx drive strength and slew rate?

I'm trying to clean up some of my compilation warnings and one I don't quite understand is "Some pins have incompelete I/O assignments ..." When I go the "I/O Assignment Warnings" report, the only pins listed are my LVDS TX pins. I tried going to the Pin Planner and see if I could change the settings, but I only get "Maximum Current (default)" option in the drive strength and the slew rate is blank. What should I specify in the QSF to get rid of the warning?

Thanks

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    There are no editable parameters for LVDS outputs. The "incomplete I/O assignments" warning is usually given together with these:

    --- Quote Start ---

    Warning: Pin "LVDS1" is a differential I/O pin but does not have its complement pin. Hence, fitter automatically created the complement pin "LVDS1(n)"

    --- Quote End ---

    The fitter reminds you to check, if you selected the correct (n) pins for differential pairs.