Phil Burgess went all demo-scene on us and made a super optimized RGB matrix panel library that supports multiple panels. It uses much more RAM but in exchange, its got great refresh, color depth and low CPU usage. If you have a panel check it out! 16×32 RGB LED Matrix — Alt High Performance Library. Phil writes –
What we’ve got here is a library for the 16×32 RGB LED Matrix that achieves both better refresh rates and lower CPU usage — producing steadier images and allowing more processing time for your own code. It also handles tiling of multiple panels, and the bit depth (maximum number of colors) is configurable. That’s the good news.
The bad news…as previously mentioned, it’s tied to a very specific hardware configuration. It relies on a few dirty tricks (or as a friend of mine says, “things that would get you an ‘F’ in a programming class”), and my concern is that the timing might be so delicate as to require tweaking if someone’s using even a different version of the compiler. So I’m hoping there might be a couple willing guinea pigs…
Bring a little bit of Times Square into your home with this 16 x 32 RGB LED matrix panel. These panels are normally used to make video walls, here in New York we see them on the sides of busses and bus stops, to display animations or short video clips. We thought they looked really cool so we picked up a few boxes of them from a factory. They have 512 bright RGB LEDs arranged in a 16×32 grid on the front. On the back there is a PCB with two IDC connectors (one input, one output: in theory you can chain these together) and 12 16-bit latches that allow you to drive the display with a 1:8 scan rate.
These panels require 12 digital pins (6 bit data, 6 bit control) and a good 5V supply, up to 1A per panel. We suggest our 2A regulated 5V adapter and then soldering a jack on such as from our extension cord. Please check out our tutorial for more details!
Keep in mind that these displays are designed to be driven by FPGAs or other high speed processors: they do not have built in PWM control of any kind. Instead, you’re supposed to redraw the screen over and over to ‘manually’ PWM the whole thing. On a 16 MHz arduino, we managed to squeeze 9-bit color (512 colors) with 50% CPU usage but this display would really shine if driven by an FPGA, CPLD, Propeller, XMOS or other high speed multi-core controller. The good news is that the display is pre-white balanced with nice uniformity so if you turn on all the LEDs its not a particularly tinted white.
Of course, we wouldn’t leave you with a datasheet and a “good luck!” We have a full wiring diagrams and working Arduino library code with examples from drawing pixels, lines, rectangles, circles and text. You’ll get your color blasting within the hour! On an Arduino, you’ll need 12 digital pins, and about 800 bytes of RAM to buffer the 9-bit color image.