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NCO mode for VGA video clock instead of PLL? — Parallax Forums

NCO mode for VGA video clock instead of PLL?

Bill HenningBill Henning Posts: 6,445
edited 2011-02-22 16:51 in Propeller 1
Ok, I think I am missing something obvious... but when I tried to run my drivers with NCO, APIN/BPIN at 0, but output not enabled, set for 20MHz output... NOTHING.

Has anyone gotten NCO mode running for VGA?

Thanks,

Bill

Comments

  • Bill HenningBill Henning Posts: 6,445
    edited 2011-02-22 16:15
    Ugh.

    Never mind... I found an old thread I started, and the response was... NCO mode does not work for VGA :(
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-02-22 16:18
    Yup, video clock comes from PLL output only. It's probably a good thing, too, since raw NCO could have way to much jitter. BTW, contrary to the book, you can use any PLL mode for video, not just the no-output version, in case you ever need an external dot clock.

    -Phil
  • Bill HenningBill Henning Posts: 6,445
    edited 2011-02-22 16:51
    Thanks Phil.
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