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Squeezing out a bit more performance from the P1 — Parallax Forums

Squeezing out a bit more performance from the P1

Hi all.

My P1 project uses a 6.25M crystal and I run the P1 at 100MHz. It's very reliable at that speed. Can I get the little bit more my application needs?

The critical sections don't quite fit. I literally need a couple more instruction cycles after optimizing as much as possible (I think!). What's a reasonable crystal freq and overclock, >100MHz I could try?

(Please don't suggest P2 it's not possible for this project.)

Comments

  • The parts are tested at 104MHz at room temperature, so you could try that.

    If you need more, 110MHz is the level above which most 2-layer board layouts will fail. (ie., those designed only for 80MHz).

    In theory you could run with an 8MHz crystal and PLL16x for 128MHz, but you'd need a really quality multi-layer design with exceptional power supplies / decoupling / layout. If you have that, test with 8MHz first! If you have an issue with temperature in your application/enclosure, just add cooling to keep the max temp rise of the P1 IC within whatever the datasheet specs as maximum.

    Vote of confidence for you... It can surely be done!

  • @brianh said:
    The critical sections don't quite fit. I literally need a couple more instruction cycles after optimizing as much as possible (I think!).

    You think. Post code. Decimating bad code on sight is my "shitty superpower".

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