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Topic: please help with WS2811 led IC (Read 37104 times) previous topic - next topic

1ChicagoDave



I'm actually a bit confused as to how the timing defined in fastspi was derived.  chipsets.h defines the triple (350ns, 350ns, 550ns), while the ws2811 spec sheet (http://www.adafruit.com/datasheets/WS2811.pdf) says a 0 is 250ns hi, 1000ns low; a 1 is 600ns hi, 650ns low.  Not sure how we get the first three numbers from the latter four, or if they should just be updated.  The comment in the code about the triple was hard for me to decipher relative to the spec sheet.

In trying to figure out the timing myself, I've become pretty stumped by the cascade diagram on page 4 of the spec (http://www.adafruit.com/datasheets/WS2811.pdf).  Can someone explain what it means, or in general how we're able to individually control all these leds with a single data line?


Any reason you're not using the Adafruit library to run them? You found the datasheet there...just another click or two and....
https://github.com/adafruit/Adafruit_NeoPixel.
Also... This may be helpful?
http://learn.adafruit.com/adafruit-neopixel-uberguide

Jhorge

I don't see the point of hi speed clocks, if a 24 bits plus reset take 8khz (120uS) cycle any mcu can do it. The 1's and 0'0 are decode on period shape and is clear represented to the timing chart...

Alanwangwang

yes, WS2811 IC don't have clock wire ,but it can be build in ic , by the way , there are a new build in ic led , it is apa102 led , which can be build in ic , but also have data ,clock wire output

keithsw1111

On an arduino mega I can drive  1200 ws2811 bulbs arranged in 24 strings of 50 bulbs using bitbanging code that uses port output to send out data to 8 light strings at once. Frame rates are fast enough to animate bitmaps read from an spi attached sd card .

Helmuth

#49
Oct 29, 2014, 06:53 am Last Edit: Oct 29, 2014, 09:21 am by Helmuth
FastLED 3.1 supports parallel output on ARM processors now. Up to 12 16 channels simultaneously.

It works also together with the OctoWS2811 lib if you wish so.

So you can drive even large led setups at the 400 fps before the most WS2811 start flickering.

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