[sigrok-dumps.git] / led / ws281x / README

-------------------------------------------------------------------------------
WS2812B LED strip
-------------------------------------------------------------------------------

This is a capture of data output to 4 LED universes of 256 RGB LEDs.
Every universe has a frame size of 768 bytes and the dumps are clocked at
roughly 100 frames per second.

Details:
 - Koen Kooi's evil vendor tree: https://github.com/koenkooi/kernel
 - PRU WS28xx firmware: https://github.com/mranostay/ws28xx-lighting-pru
 - WS2812B datasheet: http://www.adafruit.com/datasheets/WS2812.pdf


WS2812B protocol overview
-------------------------

All values have a +/- tolerance of 150 nanoseconds so the PRU firmware uses
the slightly different timing values below to sync the high/low transitions.

  Logic low  -> high 0.40 uS -> low 0.85 uS (1.25 uS)
  Logic high -> high 0.80 uS -> low 0.45 uS (1.25 uS)
  Latch      -> low 50 uS

Each LED receives and then stores the first 24-bits of GRB ordered data then
passes any more out the Data Output pin to the next LED in the chain.

This functions as a "reverse" shift register and allows the strip length not
to be defined in the protocol.


Logic analyzer setup
--------------------

The logic analyzer used was a Saleae Logic16 (at 5MHz):

  Probe       WS2812B LED strip
  -----------------------------
  1 (black)   Universe #1
  2 (brown)   Universe #2
  3 (red)     Universe #3
  4 (orange)  Universe #4


Data
----

The data contains various RGB values and frames.

The sigrok command line used was:

  sigrok-cli --driver saleae-logic16 --samples 10M --config samplerate=5mhz \
             -p 0=UNI1,1=UNI2,2=UNI3,3=UNI4 -o ws281x_4ch_5mhz.sr
Commit	Line	Data
81517080 MR	1	-------------------------------------------------------------------------------
	2	WS2812B LED strip
	3	-------------------------------------------------------------------------------
	4
	5	This is a capture of data output to 4 LED universes of 256 RGB LEDs.
	6	Every universe has a frame size of 768 bytes and the dumps are clocked at
	7	roughly 100 frames per second.
	8
	9	Details:
	10	- Koen Kooi's evil vendor tree: https://github.com/koenkooi/kernel
bd6d6407	11	- PRU WS28xx firmware: https://github.com/mranostay/ws28xx-lighting-pru
81517080 MR	12	- WS2812B datasheet: http://www.adafruit.com/datasheets/WS2812.pdf
	13
	14
	15	WS2812B protocol overview
	16	-------------------------
	17
bd6d6407 UH	18	All values have a +/- tolerance of 150 nanoseconds so the PRU firmware uses
bd6d6407 UH	19	the slightly different timing values below to sync the high/low transitions.
81517080 MR	20
	21	Logic low -> high 0.40 uS -> low 0.85 uS (1.25 uS)
	22	Logic high -> high 0.80 uS -> low 0.45 uS (1.25 uS)
	23	Latch -> low 50 uS
	24
bd6d6407	25	Each LED receives and then stores the first 24-bits of GRB ordered data then
81517080 MR	26	passes any more out the Data Output pin to the next LED in the chain.
81517080 MR	27
bd6d6407 UH	28	This functions as a "reverse" shift register and allows the strip length not
bd6d6407 UH	29	to be defined in the protocol.
81517080 MR	30
	31
	32	Logic analyzer setup
	33	--------------------
	34
bd6d6407	35	The logic analyzer used was a Saleae Logic16 (at 5MHz):
81517080 MR	36
	37	Probe WS2812B LED strip
	38	-----------------------------
	39	1 (black) Universe #1
	40	2 (brown) Universe #2
	41	3 (red) Universe #3
	42	4 (orange) Universe #4
	43
	44
	45	Data
	46	----
	47
	48	The data contains various RGB values and frames.
	49
	50	The sigrok command line used was:
	51
	52	sigrok-cli --driver saleae-logic16 --samples 10M --config samplerate=5mhz \
	53	-p 0=UNI1,1=UNI2,2=UNI3,3=UNI4 -o ws281x_4ch_5mhz.sr
bd6d6407	54