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Is it possible to have 4 PWM channels at 25 kHz?
I am posting this second answer since I realized it is possible to have 4 PWM channels at 25 kHz with 161 steps on a single Arduino Uno. This involves changing the main clock frequency to 8 MHz, which has some side effects since the whole program will run half as fast.
What should the PWM frequency be on an Arduino?
The value written should be between 0 (meaning always LOW) and 160 (always HIGH), inclusive. Only pins 3, 5, 9 and 10 are available. Attempting to analogWrite () to pins 6 or 11 will not only fail to deliver a PWM output, it will also change the frequency on pin 5 or 3 respectively.
Can you change the clock frequency on Arduino?
This involves changing the main clock frequency to 8 MHz, which has some side effects since the whole program will run half as fast. It also involves reconfiguring the three timers, which means loosing the Arduino timing functions ( millis (), micros (), delay () and delayMicroseconds () ). If these trade-offs are acceptable, here is how it goes:
What’s the PWM frequency on the Arduino Uno?
According to the Arduino reference for analogWrite(), the PWM frequency on most pins is ~490 Hz. However, it’s ~980 Hz for pins 5 and 6 on the Uno, and for pins 3 and 11 on the Leonardo.
Why do some pins have a different PWM frequency?
If you change the prescaler for a certain timer, you change the PWM frequency for the related PWM pins. I believe some timers double for other purposes like the millis (); function. If you change the prescaler for that timer, values returned by millis () will be off by the same factor.
How does a PWM work with a timer?
It works by using the first timer as the PWM frequency generator. This then loads up the second timer with a time that is the period of the required pulse width. It does this by calculating the number of timer clock cycles that result in the required period (which you set from within the program elsewhere).