I know its a subject that already came up, but still there is no one truth for it in google I would like to be able to output a square ( or PWM) on any digital pin , and set its frequency 0-20Khz .
Is there a library to do exactly that ? can it be done in background using timers ? will it affect millis() ?
Seems that there is no pure solution- one that simply do that, and not affecting the whole system.