24-Output Cape in LEDscape

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This topic contains 2 replies, has 2 voices, and was last updated by  John 2 years, 9 months ago.

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  • #1056

    John
    Participant

    Has anyone been able to get the LEDscape library converted to only 24-pin versus 48. The incredible documentation for the library left that out.

    Also, anyone have a simple explanation of how the library works with a string of pixels? (How they are addressed across 24 pins)? The library isn’t clear on what “strip” vs “frame” vs “pixel”. The obvious isn’t the actual answer so I’m hoping someone has flushed this out.

    As an example, I would “assume” that if I had LEDs on channel 7 of the board then I would need to write to “strip 7”, but that would be wrong! Please help.

    #1061

    ohararp
    Keymaster

    John, thanks for all your inquiries. Hopefully, I can answer all your questions. We are working on a “branch” that covers the remapping of the different capes we have been designing. Depending on the format it was necessary to remap some of the pins to ensure proper digital signal integrity and to simplify routing. You can find the branch at the link below. This new branch is one step closer to having a html based json configuration. Think the same setup page as a wifi router.

    https://github.com/Yona-Appletree/LEDscape/tree/pru-program-generation

    Part of this configuration will allow you to set the number of channels (0-48) and number of pixels (0-512). Additionally, you can also specify the version of the pin mapping that you need. As part of this we are also now supporting WS2801 leds.

    For your example, say you had 64 leds per strip. To write to the first led in strip 7. You would be writing to the memory location 448 (7*64+1=448). I hope that helps.

    #1069

    John
    Participant

    I’ll give it a try. I’m new to this board so it will take me a little experimentation. The LEDscape library doesn’t do a direct memory write at the high level. Do you have an explanation of the function that writes? It asks for strip number, frame number and pixel. I’m not sure what each of these mean in the function.

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