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composite video benefits with Propeller over digital VGA/HDMI



  • cgraceycgracey Posts: 14,124

    I've got 960x540 working at 60fps on HDMI, which is called "qHD" for quarter HD. It matches up with the pixels nicely on a 16:9 HDTV.

  • well.... thanks everyone. I don't quite follow all the discussion, but it seems that some new exploration happened and some have a better understanding of potential or limits.
    In any case. I ended up getting just a 4" HDMI interface touch display for the moment that I suspect will work good enough as I'm already using a 10" HDMI display with the DV connector that seems to work for now.

  • pik33pik33 Posts: 2,342
    edited 2024-01-21 15:59

    @cgracey said:

    @pik33 said:

    I wrote a 720p driver tonight, but my Samsung TV's won't display the signal. I am doing 720p at 24fps, which needs a clock of 297MHz, which is doable. I think I am generating the signal right, but it won't show. Seems like 640 x 480 is maybe the practical limit of P2 HDMI these days.

    If you reduce the refresh rate to 50 Hz, 1024x600 is possible on HDMI at ~340 MHz. All monitors I tried this on work OK, although timings are somewhat stretched over limits - 1024x576 may be more stable, but there are 1024x600 HDMI LCD displays. We tested this with Waveshare touch display and even got touch reports from the usbnew driver.The example of using this resolution is my Basic interpreter for EC32 ( )

    That would be great, but I worry it's very close to the timing limis of the P2. That's amazing you are able to achieve that. Do you feel confident enough in it that you would sell it as a commercial product?

    It depends.
    As a toy, entertainment or educational purposes, yes. The intepreter and media player, both using 336 MHz on EC32 and 1024x600 drivers, worked for me (and still work) for many hours without any hardware failure. If failed, there was my software bug.
    For industrial environment, not. Overclocking is too extreme, no margin for temperature and electromagnetic noise.

    For an UVC disinfecting robot, I used 800x480 HDMI screen at 285 MHz. There weren't any problems with the P2 in this robot, while the environment inside the robot was noisy and warmer than the room temperature (power supplies for 800W UVC lamps, stepper motors and BLDC controllers, a lot of switching PSUs, cameras, etc.

  • Re: Long COVID

    Real quick, I am much improved. The startups I am part of made it through the pandemic and we are very near funding for some advanced additive metal manufacturing machine projects.

    Check this out:

    US manufacturing base has been shrinking by about 5 percent per year for a long while now. At the same time, the necessary investments into new tech, which pretty much is additive (40 years old compared to about 200 for machining), have not been made to the degree necessary to just backfill old tech losses with new. The result is the US is way behind!

    Additionally, the people who really knew their stuff have basically left the game. There is rote manufacturing going on all over the place. They just do what the process docs call for. (Which is crazy) Making changes and even making new stock is a growing nightmare.

    The startup is aimed right at that problem. Additive metal is heating up as plastics did, and still is to a degree. Think near net shape starting materials vs starting with a block of expensivatanium!

    The other matters, family, granddaughter and all that are playing out well. She is showing interest in the stuff and growing up nicely. I grumble about raising a kid again, but the truth of it all is I am lucky to have her!

    Re: High definition composite

    I see Roger is on it! (Nice)

    All this work to make use of the 4k and higher displays is pretty exciting! I am following with great interest for when I circle back around to this stuff.

    Anyhow, I do not intend to muddy the thread up. Cheers everyone.

  • evanhevanh Posts: 15,049

    Good to here things do improve.

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