Different GPIO PWM outputs with different frequencies at the same time

[GiuanniSomething]

Hi! I was wondering if it was possible to drive two different devices at the same time but while using two different PWM frequencies.
I needed to run a solenoid which needs a frequency range from 11 Hz up to 80 Hz, while i need to simultaneously control a dc motor, but this motor has to work from 3000 Hz up to 6000 Hz. I managed to lower the limit of the analogWriteFreq to 10 Hz by modifying the function inside wiring_analog.cpp . I did a simple test with a potentiometer and two leds, where i tried to use AnalogWriteFreq(11) on a LED which runs on the first core, and then analogWriteFreq(3000) on another led which runs on the second core, however this doesn't work (both leds won't turn on) and i honestly have no idea why, because i'm new in electronics and i'm still learning. Can someone help me out? Thanks in advance!

Here's the code:

`void setup() {

pinMode(LED_BUILTIN, OUTPUT);
pinMode(0, OUTPUT);
pinMode(28, INPUT);
Serial.begin(38400);

}

void loop() {

analogWriteFreq(11);
analogWrite(LED_BUILTIN, map(analogRead(28), 0, 1024, 0, 256));
Serial.print("pot: ");
Serial.println(map(analogRead(28), 0, 1024, 0, 256));
Serial.println("\n");

}

void setup1() {

}

void loop1() {

analogWriteFreq(3000);
analogWrite(0, map(analogRead(28), 0, 1024, 0, 256));

}`

[trimarco232]

Hi,

1. you don't have to use 2 cores for this
   the pwm peripheral has 8 timers which have each 2 pwm channels
   so you can can have 8 pwm pins with 8 different periods (and duty)
2. please don't set your peripheral continuously in your loop : let it time to act

[git2212]

I was wondering if it was possible to drive two different devices at the same time but while using two different PWM frequencies

Yes, you have to use pins which belong to different slices a.k.a. channels. Use the A pins in the slice.

I managed to lower the limit of the analogWriteFreq

bit-banging PWM when you have a subsystem which is capable of MHz operations is like driving 15Kph in a Ferarri.

Can someone help me out

Well, I'd suggest you start with something like khoih-prog/RP2040_PWM

From personal experience the following may apply to you: PWM on the PICO/2040 can be frustrating as it has a lot of shall we say odd and unexpected behavior. Stay away from phase-corrected mode until you are very well versed in the inns and outs of PWM on PICO/2040. Inverting the phase has it's own "charm" shall we say so again, save it for later. If you need to synchronized the PWM signals you are getting into a whole other area of complications... this PI forum post can give you an idea, but get a stiff drink in hand before you delve in lol.

Be mindful when reading the spec-sheets, marketing people love to pepper them with fancy terminology hoping they sell more chips, e.g. Delta-Sygma bla, bla,... completely irrelevant to most use cases most programmers are likely to deal with.

PWM is likely going to be a steep learning curve, strap in and good luck :))

Cheers.