Driving SK6812 RGBW LEDs

This article will cover one possible way to drive SK6812 addressable LEDs, specifically the 32bit variant used for RGBW LED chips.

The SK6812 is similar to the, perhaps more common, WS2812B in that the overall bit-time is the same (1.2us) but the timing is slightly different. The WS2812B uses 350ns/900ns for '0' and 900ns/350ns for '1'. The SK6812, on the other hand, uses 300ns/900ns for '0' and 600ns/600ns for '1'. Here's a table from the datasheet:






The code included in this article is hardcoded for 64MHz system clock and achives the required timings, as can be seen in the following images:

0-pulse timing:


1-pulse timing:


And the interpixel delay (well below the 80us so no risk of data being latched prematurely):




How to us it:
First we need to tell the "driver" how many pixels we intend to drive, this causes the "driver" to allocate memory (4 bytes per pixel) for the LED string. Then we need to tell the driver which pin we want it to use as the signal output, using a LAT registers is highly recommended, and then we set that pin as an output and make sure it's low. (Note that you may also need to disable analog functionality on the pin in use). Last step is to include the "driver". This is what it might look like:
At this point we have four arrays called Red, Green, Blue and White respectively, each with a size defined by the PIXELS constants (24 in the above example). If we want to light up the third pixel with a magenta looking color at 50% intensity we can do:Or, a very basic running light:I've created a forum thread where sugguestions, discussions and questions can be handled.