Sparkfun 8x8 RGB Led Matrix with PWM

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Per title, it's the sparkfun RGB backpack. I got bored and wrote a framebuffer for it and ported over some monochrome display hacks from peggy 2.0. Then I added color support. 12 bits per pixel, non log-scaled, but it still looks pretty good.

Adapted from mono display hacks for the peggy board. www.solivant.com/peggy2/

PS - There are a few other display hacks that I didn't get into this video. This is part of some work I did today to get a framebuffer w/basic drawing apis up and running. Going to reuse it with an 8051 core on the FPGA displays.

kenliu, lisasutt, okini393939, and 9 other people added this video to their favorites.

  1. Sonny W. 64 months ago | reply

    You rewrote the backpack code to support PWM? Awesome. You rock!

  2. scottie4442 64 months ago | reply

    I am trying to do a light show for a jukebox that I am working on and would like to use the backpack controller to do the lights. Is there anyway that I can get the PWM firmware for the backpack from you?

  3. Furan 64 months ago | reply

    @scottie4442: This code is actually written in such a way that the backpack is not doing SPI at all, all the rendering is being done on the fly on the microcontroller. I've also since rewritten the code for an atmega168 that I replaced the atmega8 with and changed out the resonator from the 8mhz one to a 20mhz one. I'm not sure what I have will be useful to you. You might try this guy's work though:
    www.microframework.nl/projects/24x16-rgb-display-with-pwm/
    -Ian

  4. shea241 64 months ago | reply

    very nice. i'm a big fan of these led displays, and 12-bit color sounds fantastic.

  5. .:madworm:. 58 months ago | reply

    Hi, I'm an admin for a group called 64-pixels, and we'd love to have this added to the group!

  6. SparkFunElectronics 54 months ago | reply

    Hi, I'm an admin for a group called SparkFun Projects, and we'd love to have this added to the group!

  7. hackmancoltaire 47 months ago | reply

    @Furan So you changed the atmega8 to an atmega168 and changed out the resonator, is that why the refresh rate on this panel is so fast? The default pack that they're selling now seems to have a REALLY low refresh rate. Unless I'm doing something wrong, which is entirely possible. :-/ The refresh rate on the current boards is like 1fps.

  8. Furan 47 months ago | reply

    I rewrote all of the display code, I'm not sure what they were doing. One thing to note is the code I wrote runs right on the backpack. It is not controlled via SPI.

    Basically, fast interrupt timer, scanout a single line every time it fires, do PWM either evenly over the whole display (I prefer) or scanout the single line on every timer interrupt until you've finished pwm, then proceed to the next.

    I hacked up this code last year on new year's day and it's not in any position to be released but I could probably clean it up for perusal.

  9. hackmancoltaire 47 months ago | reply

    @Furan I'm trying to take the default off the shelf Sparkfun LED matrix backpack and get as many frames per second as possible. Sounds like you had a pretty custom approach, which I'd be interested in learning. I'm trying to build a persistence of vision device with these and at the moment the most I've been able to squeeze out of it is 3FPS.

  10. SparkFunElectronics 47 months ago | reply

    @Furan, so if you aren't sending/receiving anything via SPI, are the animations hard coded into micro-controller?

  11. Furan 47 months ago | reply

    Yes. They're randomly generated though.

  12. hackmancoltaire 47 months ago | reply

    @SparkFunElectronics @Furan With a little adjustment to the speed of the SPI clock I was able to get much greater speed to the pack. I've got frames in excess of 60fps. Somewhere in the range of 250fps. I'd like to get generated displays like the one in this video as well, along with animated frame based sequences. We'll see if I can. I'll post some video once I have it all working.

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