[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 WS281x firmware: https://github.com/mranostay/ws28xx-lighting-pru
 - WS2812B datasheet: http://www.adafruit.com/datasheets/WS2812.pdf


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

All values have +/- tolerance of 150 nanoseconds so the PRU firmware uses
slightly different timing value 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 the 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 analzyer 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
	11	- PRU WS281x firmware: https://github.com/mranostay/ws28xx-lighting-pru
	12	- WS2812B datasheet: http://www.adafruit.com/datasheets/WS2812.pdf
	13
	14
	15	WS2812B protocol overview
	16	-------------------------
	17
	18	All values have +/- tolerance of 150 nanoseconds so the PRU firmware uses
	19	slightly different timing value below to sync the high/low transitions.
	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
	25	Each LED receives and the stores the first 24-bits of GRB ordered data then
	26	passes any more out the Data Output pin to the next LED in the chain.
	27
	28	This functions as a "reverse" shift register and allows the strip length not to
	29	be defined in the protocol.
	30
	31
	32	Logic analyzer setup
	33	--------------------
	34
	35	The logic analzyer used was a Saleae Logic16 (at 5MHz).
	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