BeagleBone Black and FPGA Driven LED Wall

LED Wall

 

This is 6,144 RGB LEDs being controlled by a BeagleBone Black and a FPGA. This gives the display 12 bit color and a refresh rate of 200 Hz. [Glen]‘s 6 panel LED wall uses the BeagleBone Black to generate the image, and the LogiBone FPGA board for high speed IO.

[Glen] started off with a single 32 x 32 RGB LED panel, and wrote a detailed tutorial on how that build works. The LED panels used for this project have built in drivers, but they cannot do PWM. To control color, the entire panel must be updated at high speed.

The BeagleBone’s IO isn’t fast enough for this, so a Xilinx Spartan 6 LX9 FPGA takes care of the high speed signaling. The image is loaded into the FPGA’s Block RAM by the BeagleBone, and the FPGA takes care of the rest. The LogiBone maps the FPGA’s address space into the CPU’s address space, which allows for high speed transfers.

If you want to drive this many LEDs, you’ll need to look beyond the Arduino. [Glen]‘s work provides a great starting point, and all of the source is available on Github.

[Thanks to Jonathan for the tip]

Comments

  1. Damn… that’s exactly what I wanted to do a couple of years ago! congratulations!
    Idea for future improvement: add a dvi port to connect it to your computer

  2. mike says:

    At 600x400mm, although it’s impressive, it’s not exactly a ‘wall’…

    When I used to work as a stagehand I dealt with plenty of what I remember as 20×15 arrays of 8×8 LED blocks, roughly 2000x1500mm overall. Maybe 20 or more of these would be assembled together to create giant video backdrops for the performer. 6000 LEDs here is crazy, but 384000+ is insane. Some LED manufacturer must be making big money from the entertainment industry…

    • bikerglen says:

      The most impressive video wall installation I’ve seen is the Comcast building lobby in Philadelphia. It’s the world’s largest 4mm pitch LED video wall w/ ~10 million RGB LEDs.

  3. Waterjet says:

    So… the FPGA does all of the hard work and the BBB (Dark Ritual) just generates the image and passes it off to the FPGA, which does all of the heavy lifting?

    • bikerglen says:

      Exactly. For example, the software to display a static image pushes the image into the FPGA over the GPMC bus then quits. The FPGA drives the panels from there.

      • Mike Szczys says:

        A perfect example of why you might want to marry an FPGA with an embedded Linux system. The BBB is just sitting there waiting to do all kinds of cool visualizations without having to bother with the particulars of driving the display.

    • Sweeney says:

      Pretty much, yes. FPGAs are good at high speed IO with precise timing. Better yet they are inherently highly parallel, so rather than bumping up the clock further he could have set up a second data bus and run that in parallel with the first.

      What they are less good at is complex control logic, which is why it is common to implement a soft CPU core in an FPGA design for that kind of work, or with the latest ZINQ/ Cyclone V designs include one or more hard ARM cores on the chip.

      • bikerglen says:

        One common task for an internal CPU core is running a complete TCP/IP networking stack. This is often less expensive than adding an external CPU to the design to run the same networking stack.

    • Alvie says:

      Actually, it is not as impressive as it looks. FPGA can drive things way faster than this. I am myself waiting for such panels to test a 15 bit color output, and i had to use a very slow clock to drive them without much noise. When it arrives and after some tests I’ll publish some info.

      Alvie
      ZPUino project
      http://www.alvie.com/zpuino

  4. Dan says:

    Wondering if the BBBs PRU was an option to replace the FPGA – http://www.element14.com/community/community/knode/single-board_computers/next-gen_beaglebone/blog/2013/05/22/bbb–working-with-the-pru-icssprussv2

    Not sure if it was up to the job but this seems like the sort of thing it’s good at.

  5. default_ex says:

    Ooo. Boxing in the leds with opaque boxes and frosted glass covers would make a wicked plasma effect.

  6. Wiljan says:

    Just been on NAB2014 where I did see a LED wall from http://www.silicon-core.com/products/magnolia-1-5
    Based on 1.5mm pitch and 4K resolution (3840×2160) with over 8.300.000 RGB leds 4,8m x 2.7m.
    This was amazing :-)

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