Using the Teensy's DMA capability, the OctoWS2811 can drive eight LED chains in parallel, which means it can update everything eight times faster.
All of which leads me to some interesting information I discovered while chatting with Paul Stoffregen, one of the founders and owners of PJRC.com. One of PJRC's products is the Teensy 3.1 Arduino-compatible development board, which is an incredible bargain at only $19.80 fully assembled (wow).
The Teensy 3.1 is based on a Kinetis MCU chip from Freescale. The Kinetis boasts a 32-bit ARM Cortex-M4 processor core running at 72 MHz. The core in the Teensy features 256 KB of Flash and 64 KB of SRAM.
Of particular interest to us here is the fact that the Kinetis also has an eight-bit dynamic memory access (DMA) capability. This leads us to PJRC's OctoWS2811 display library, which works with Adafruit's NeoPixels and all other WS2811/2812-based addressable LEDs.
Using the Kinetis DMA capability, the OctoWS2811 can drive eight chains in parallel, which means it can update everything eight times faster. Minimal CPU impact and double buffering allows for complex animations that cannot be achieved using traditional Arduino-compatible platforms and libraries. Consider this video, which features 2,000 LEDs controlled by two Teensy controllers.
Did you notice my saying "minimal CPU impact?" This is actually really exciting. When you use the OctoWS2811 library to upload the data to your LED chains, the CPU hands control of this task over to the DMA engine without disabling any of the interrupts or anything like that. This leaves the CPU free to perform other tasks (like the FFT for my BADASS Display).
Below we see videos of a few projects that have used the combination of Teensy boards and the OctoWS2811 library to drive thousands of LEDs to great effect. From top to bottom, these are the Wall of Light, the Penrose Triangle, the Skyline LED Wall Booth, and the CrashSpace Light Show.
Well, what can I say? I am very, very impressed. This certainly looks like a strong contender to drive a future incarnation of my BADASS Display. Also, Paul has been telling me about an amazing audio library he's been working on, but we will leave that for a future column. In the meantime, what do you think of the Teensy 3.1 and the OctoWS2811 library?
— Max Maxfield, Editor of All Things Fun & Interesting