APA102 Huh? Today I decided to hook up my Teensy3.1 to a roll of

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APA102 Huh?
Today I decided to hook up my Teensy3.1 to a roll of APA’s from Adafruit. I started with a fresh download of the library this morning, and uploaded the 100line demo sketch. And this is what I got in the video.

In my attempt to figure this out I have tried the following:

  1. confirmed the correct data and sck pin are to the LEDs (using hardware SPI)
  2. tried 2 different power supplies with no alleviation
  3. applied power to both ends of the strip
  4. tried using bitbanging on 23, 22
  5. changed NUM_LEDS and various other sketches and still no alleviation.

EDIT: the issue was related to the data rate for the SPI bus. Adafruit APA’s seem to freak out a bit when talking too fast to them.

6ec092d9940973dbbecbc5ee1a3cd967.gif

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The first 30 LEDs are fine, then after that, they start to flicker but still show the correct color. About the 60 mark the data is corrupted and nothing but white and flickery to the end.

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Are you using an 74HCT245 buffer chip? I had some similar problems with WS2812B strips.

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Try changing to a lower clock speed - some APA102’s have issues running at the max SPI data rate - FastLED.addLeds<APA102,DATA_PIN,CLOCK_PIN,DATA_RATE_MHZ(12)>(leds, NUM_LEDS);

(Note - I’m currently running 784 APA102 leds off of a single Teensy 3.1)

Also you may need to inject power in the middle there.

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Also also - double check the solder joints at the 30 and 60 led marks - I remember someone mentioning that the join at those points was not great on strips that they had received.

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The data rate was the issue, THANK YOU @Daniel_Garcia

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@Jon_Burroughs Curious, what did you reduce it to to get it to work?

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@marmil 14 removed all the artifacts. At 12, the first LEDs on the string were flickering.

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@Jon_Burroughs ​ So a higher speed worked better?