Again a question about IR + AVR + WS2812:

Archive FastLED Archive
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Again a question about IR + AVR + WS2812: @Daniel_Garcia writes “The problem is not with the library, the problem is with the combination of LEDs (neopixel/ws2812) and the MCU being used (air based arduinos). The WS2812 timing requirements are pretty tight - so interrupts have to be disabled while writing out data for them.”

What I understand is: On an AVR it is (so far) impossible to have an ISR so short that it could be completely executed while pushing out a frame inbetween sending the data of 2 LEDs. So the interrupted frame will be incomplete because the required timing grid is too tight.

If the animation itself is programmed slow and smooth - who would care about one incomplete frame inbetween? Would it even be visible?

So why not just allowing interrupts in general? What am I overlooking here?

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Because on AVR, the SYSTICK interrupt fires once every millisecond. This means that the frame writing will always be interrupted every millisecond. Which means that you couldn’t have more than about 30 leds on AVR.

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Thank you, now I see the problem.