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P2-Eval (64000-ES) first impressions - Page 2 — Parallax Forums

P2-Eval (64000-ES) first impressions

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  • cgraceycgracey Posts: 14,152
    That is good news. It may be that the big switcher supply correlates to the video scan because of the DAC pin loads.
  • jmgjmg Posts: 15,173
    Tubular wrote: »
    Ok on the "VGA video quality vs selected voltage regulator front"

    I'm pleased to say I had the sources mixed up, and the 8 small LDOs do indeed result in better video quality than the big 3v3 switcher.

    That makes a lot more sense.... :)

  • yes, I'm mighty relieved too.

    The real challenge is realizing the silly error, *before* diving too deeply into the details.

    While having solved the LDO performance mystery is a relief, during these travels I've found a few more rabbit holes to play with
  • Here's a thermal pic of P2-Eval after about 30~60 mins for the temp to climb and stabilise. Clock freq is ~ 360 MHz

    This is just the P2-eval with its supplied rubber feet sitting flat on a table. No fan

    Ambient was quite hot; temp rise is about 29 degrees, so its really a worst case scenario (other than being in an enclosure, will get to that soon)


    320 x 240 - 87K
  • Cluso99Cluso99 Posts: 18,069
    Don't let the smoke out :(
  • 56C at the back of the PCB should still be within a "safe" range before letting smoke out for the chip. Since all the heat dumps out the ground pad, the chip itself won't be that much hotter than this measurement.

    It's not uncommon for modern GPUs to hit 70-80C under load, and that's with fairly extreme active cooling.
  • Cluso99Cluso99 Posts: 18,069
    Even some old chips mid 80s) used to run ~70C.
  • RaymanRayman Posts: 14,646
    edited 2018-12-28 13:26
    Tubular wrote: »
    Ok on the "VGA video quality vs selected voltage regulator front"

    I'm pleased to say I had the sources mixed up, and the 8 small LDOs do indeed result in better video quality than the big 3v3 switcher. ...

    Sound like I should move the V0007 jumper from the VIO position to the 3V3 position, right?

    Ok, it's pretty well shown in the ES Eval Board Guide pdf...

    Tested it... It does fix the banding issue with all white screen...

  • VonSzarvasVonSzarvas Posts: 3,450
    edited 2018-12-28 17:28
    VonSzarvas wrote: »
    msrobots wrote: »
    I'll share the step-by-step doc tomorrow. At least hopefully it will help improve some things.

    Here goes the setup to give your P2-EVAL a reset-free life on Windows.

    These details can be merged into the P2 docs sometime in the future, but for now this pdf version was a quick way to share the concept.

    @msrobots Sorry to say that this won't help fully with FLiP or Activity Board. I tested both, and added some notes at the end of this doc.

    To be clear about what this is...
    - these settings refer to Windows OS, and stop the reset (DTR pulse) when plugging / un-plugging the USB cable. That behaviour might be preferable to some, although I think for monitoring serial output of an already running system (for example), this can be a handy configuration.
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