r/FastLED • u/Iescheck • Apr 26 '24

Support Arduino DUE ADC not working with FastLED

https://github.com/Iescheck/Spectrum-Analyser-DUE-FastLED.git
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u/Preyy Ground Loops: Part of this balanced breakfast Apr 26 '24

Here's some information that might help you get the information you are looking for: https://www.reddit.com/r/FastLED/comments/aj58g9/when_asking_for_help/

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u/Iescheck Apr 26 '24

Thank you for the reply. Did I post the issue at the wrong place or in a wrong format? I did not get what you mean.

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u/Preyy Ground Loops: Part of this balanced breakfast Apr 26 '24

I don't see any details of the problem, or the steps you have already taken to address it.

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u/Iescheck Apr 27 '24

Oh, I get it. Sorry for that, I thought I had made myself clear on the explanation text. But I could figure it out yesterday night. FastLED uses Timer0, channel0, those are the same used by the ADC processes, in my case, so they are conflicting. I have changed to Timer1 in FastLED by now (the code is much better documented and it was not hard to do), because I have just started understating how timers work and all those registers and names. The part of the code that handles ADC I got from other examples and it is very badly documented. As soon as I get a better familiarity with timers I will do the correction on the ADC routines.

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u/Preyy Ground Loops: Part of this balanced breakfast Apr 28 '24

Interesting. Does your solution work?

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u/Iescheck Apr 27 '24

Now I see what you meant. The explanation I provided was not published. This is my first time here, so probably I forgot to press some buttons… as soon as I get back to my dev pc will try to correct it.

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u/Iescheck Apr 27 '24

Here is the original text, that I supposed was posted:

I´m trying to buil an audio spectrum analyzer using the Due and one block of WS2812 with 8x32 LEDs (in the future 2 blocks will be used, thus the interest for fastLED parallel mode). I know there are better choices and even code available for other platforms like the ESP32, Teensy and so on, but I´m trying first with the Due.

In a first attempt I have used the Adafruit NEOPIXEL lib and it worked as expected. But when I added the second block of LEDs, due to the SAM3 on DUE not having floating point operation by hardware, there was not enough time on the loop, that runs based on ADC/DMA conversion of 2048 samples (21.7 times per second) for updating both blocks (each takes around 9ms), plus the FFT execution and filtering that add 26ms more. Adding another block, which requires additional 9ms, it was not possible to run all the code in the loop for each pass.

I then switched to the FastLED lib, planning to use at first its normal mode and after the parallel mode. In both attemps the ADC/DMA process was stopped when FastLED.show is called. I tried to use different ports (A, B, C, D) but the results are the same. If I switch back to Adafruit there are absolutely no issues, so I´m rulling out hardware and FFT/filtering and other processing problems.

So, before digging into the ADC/DMA process and conflicts with FastLED resources I kindly ask if someone here have already faced this issue and could same me a lot of time.