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New 4.3" touchscreen LCD for Propeller: "used" screens almost free w/purchase. - Page 24 — Parallax Forums

New 4.3" touchscreen LCD for Propeller: "used" screens almost free w/purchase.



  • radialrandyradialrandy Posts: 78
    edited 2011-07-28 11:58
    How much memory does it take to do 2bit graphics on the full 4.3" lcd? Can ya not use a secondary eeprom to store the bitmap?
  • RaymanRayman Posts: 12,627
    edited 2011-07-28 13:16
    Ok, funny you mention that because I do have a functioning external memory solution: FlashPoint RamPage

    I can currently show full-screen 6-bit images directly from SRAM or FLASH.
    Of course, it could do 2-bit even better.

    Still need to find a way to interleave updating the screen with drawing to the screen.
    For 2-bit it shouldn't be too hard.

    Anyway, I have the hardware to do it, just need to find time to get the software side right...
  • RaymanRayman Posts: 12,627
    edited 2012-10-30 05:44
    Got a real puzzle here with Quickstart and the "Like New" screens...

    I've tested hundreds of these screens in several different propeller setups and I've never seen a difference between the "used" and the "like new" types.
    But now, when I (and a customer) use Quickstart, the vertical sync is messed up with the "like new" screens, but works fine with the "used" ones.

    I did find that a small capacitor, anywhere from 2 nF to 100 nF, will fix the problem when placed between either HS or VS to ground.
    But, a pull-up resistor on VS doesn't help.

    So, I'm finding this all really bizarre but repeatable. But, I don't see what is different about Quickstart and all the other boards... Also, I'm not sure why
    the two types of screens are showing this difference, when my understanding is that they are the exact same model...

    Actually, I've just heard that the problem also happens on a breadboard with DIP prop... So, not just Quickstart...
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