TCCR1B = TCCR1B & B11111000 | B00000011 // set timer 1 divisor to 64 for PWM frequency of 490.20 Hz (The DEFAULT)

TCCR0B = TCCR0B & B11111000 | B00000011 // set timer 0 divisor to 64 for PWM frequency of 976.56 Hz (The DEFAULT) NOTE: Changing this timer 0 affects millis() and delay!

In the void setup() part of your Arduino code, set or clear the CS02, CS01, and CS00 bits in the relevant TCCRnB register.įor Arduino Uno, Nano, YourDuino RoboRED, Mini Driver, Lilly Pad and any other board using ATmega 8, 168 or 328 //- Set PWM frequency for D5 & D6.

If you use the default values set by the Arduino Diecimila's bootloader, these are your PWM frequencies: pins 6 and 5 must be at the same frequency). But you can't set different frequencies for pins that are controlled by the same prescaler (e.g. Arduino pins 11 and 3 are controlled by TCCR2B, so they may be set at a third frequency. Arduino pins 9 and 10 are controlled by TCCR1B, so they can be set at a different frequency from pins 6 and 5. For instance, Arduino pins 6 and 5 are both controlled by TCCR0B, so you can set Arduino pins 6 and 5 to output a PWM signal at one frequency. Since there are three different prescalers, the six PWM pins are broken up into three pairs, each pair having its own prescaler. There are three such Timer/Counter registers: TCCR0B, TCCR1B, and TCCR2B. The prescaler is a 3-bit value stored in the three least significant bits of the Timer/Counter register: CS02, CS01, and CS00. Assuming you are using an UNO, this counter's clock is equal to the system clock divided by a prescaler value. It follows logically that the frequency of the PWM signal is determined by the speed of the counter. In the example above, a square wave is generated because the pin is HIGH from counts 0 to 127, and LOW from counts 128 to 255, so it is HIGH for the same amount of time it is LOW. When the counter is less than the PWM value, the pin outputs a HIGH when the counter is greater than the PWM value, the pin outputs a LOW. The 8-bit PWM value that you set when you call the analogWrite function: analogWrite(myPWMpin, 128) Outputs a square wave is compared against the value in an 8-bit counter.

On the Arduino UNO and YourDuino RoboRED etc., pins 3,5,6, 9, 10, 11 can be configured for PWM output.

1.3 For Arduino Mega1280, Mega2560, MegaADK, Spider or any other board using ATmega1280 or ATmega2560.

1.2 For Arduino Uno, Nano, YourDuino RoboRED, Mini Driver, Lilly Pad and any other board using ATmega 8, 168 or 328.

1.1 How do you change the PWM frequency?.

1 Changing PWM Frequency on the Arduino.

Pwm pins on arduino mega 2560