I want to output 100kHz PWM to a pin on my arduino. Wondering if anyone has code that can do this or can point out any error in the codes I tried. Here is my naive approach: #define TOGGLE(x) digitalWrite(x, digitalRead(x) ? LOW : HIGH) float DUTY_CYCLE = 0.5; // 0.0 - 1.0 float FREQUENCY = 100000…

Don't use floating point math if you expect something to run fast.

From Your naive attempt: [image] alexroz: delay(1.0/FREQUENCY * DUTY_CYCLE * 1000); First: 1.0 divide by frequency give 0.000 001. Mult 0.5 gives 0.000 000 5. Mult by 1000 gives 0.000 5. 0.0005 milliseconds.... Read Arduino/reference for the delay function. It accepts integer number of mill…

Railroader is right, you could use delayMicros() keeping in mind that the delay you're looking for is 5 microseconds for 100khz, or you could use the micros() function to create a timer without using the delays.

Taking what you said and @Railroader , I tried using the delayMicroseconds function and hardcoded the delay to 5 microseconds. This is better, but not quite there. On the oscilloscope I read 62 kHz. #define TOGGLE(x) digitalWrite(x, digitalRead(x) ? LOW : HIGH) //float DUTY_CYCLE = 0.5; // 0.0 - 1.0…

Can't you use a PWM enabled pin?

I did read up on that but couldn't get it to work. If you have any code that I can use or resources I can read to learn how I could do that, that would be great. I tried using the library "RP2040_PWM" as mentioned in the original post to no avail.

Yep, this works. I changed the two lines of code to delayMicroseconds(2); and got around 97.5kHz which is good enough for my purposes. Thanks.

It’s kind of a pity that the Arduino PWM library couldn’t be gotten to work. I regularly use PWM on an RP2040 board programmed in MicroPython and 100 kHz is a walk in the park. It might be worth the time it takes to troubleshoot the errors you were getting while trying the Arduino library.

[image] alexroz: TOGGLE(PIN); You need to take into account how long it takes to execute the TOGGLE(PIN): Also the waveform might be slightly asymmetrical, as it takes extra time to go from the second delayMicroseconds(5); , and back to the top of loop.

If I need to do similar processes more often in the future I'll definitely look into it.

100kHz PWM on Arduino Nano RP2040 Connect

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Railroader August 8, 2023, 9:56pm 7

There's delay caused by the execution time of the code. Lower that 5 to 4? Any difference?

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100kHz PWM on Arduino Nano RP2040 Connect

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