Bought a few pedalSHEILD MEGA kits a while ago, finally had time to build one up. Wrote a simple program to display the state of the buttons / switches just to test everything out. and things were fine. Copied the "clean effect" code into my test program and it basically works, but the output was noisy with the effect enabled.
After reading the forum, I copied the "sine wave generator" output code, and used the toggle switch to enable that mode. The "sine wave" generator output is basically clean without the noise (although it doesn't quite sound like a sine wave... I'll have to look at it on the 'scope).
This led me to believe that the noise problem was on the input side. So, I forced the inner loop of the "clean effect" to read 0, and when that sample is passed to the PWM, there is no noise. So I guess the ADC is picking it up.
I'm going to spend some quality time reading the ADC section of ATmega 2560 data sheet, but would appreciate any insights that experienced pedalSHIELD hackers might have on this.
Oh, I'm using an ELEGOO Mega 2560 -- I've had good luck with these devices so far, but I can hunt down a genuine Arduino Mega 2560 if really needed.
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