Frequency changing of pwm pins of arduino uno

[shirazhill]

hii.
I am trying to change in Arduino Uno the PWM frequency in pin 3 to 2HZ and I don't know what is the correct command which does that which resemble this conversation in the next command line:
TCCR2B = TCCR2B & B11111000 | B00000001; // for PWM frequency of 31372.55 Hz
thank you

[b707]

@shirazhill

I am trying to change in Arduino Uno the PWM frequency in pin 3 to 2HZ

Impossible.
The minimum PWM frequency for pin 3 Arduino Uno - 30 Hz

For 2 Hz use software PWM.

[b707]

@Delta_G

thats around 6Hz I think. (16000000 / 1024 / 256)

.... about 61
If you take the phase correct PWM, you can have a frequency about 30 Hz.
It is a lowest possible value, as far I know

[kolaha]

How to set PWM frequency to 1 Hz on an UNO

I would like to set a pwm output on my UNO to run at a 1 Hz frequency and then, by analogWrite, set it at 10% or 90% dutycycle. Can that be done? If so, how do I do it? The background is my need to waist some current in a low power consuming project to keep the powering powerbank away from cutting off. In a test project using millis() the frequency of 1Hz and 10% dutycycle does the trick. Now I want to do the same in a sketch that hangs waiting for inputs go high and go low so millis() will pro…

[kolaha]

@shirazhill note, 2Hz is possible only with 16 bit timer. UNO has only one such, the Timer1 and corresponding pins are D9 and D10. pin D3 lowest possible PWM frequence is ~30Hz.

[Railroader]

I used some 270 Ohm load resistor I think. Note that that tops the load of and I2C LCD and a NEO6-M GPS.

Here's the code I got from helpers:

  //1Hz 90% dutycycle
  pinMode(9, OUTPUT);                               // Set digital pin 9 (D9) to an output
  TCCR1A = _BV(COM1A1) | _BV(COM1A0) | _BV(WGM11);  // Enable the PWM output OC1A on digital pins 9 and invert output
  TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS12);     // Set fast PWM and prescaler of 256 on timer 1
  ICR1 = 62499;                                     // Set the PWM frequency to 1Hz: 16MHz/(256 * 1Hz) - 1 = 62499
  OCR1A = 6249;                                     // Set the duty-cycle to 10%: 62499 / 10 = 6249

  pinMode(10, OUTPUT);                               // 1 Hz pulse output on digital pin 9 (D9)
  pinMode(13, OUTPUT); digitalWrite(13, LOW);// Make board LED go off
  delay(10);//allow pwm timers to start

[kolaha]

@Railroader

ICR1 = 62499;

for 2 Hz

ICR1 = 31249;