user18574: The max PWM frequency that can be achieved with an Arduino is by using the PWM fast mode with the pre-scaler set at 1 and the TOP counter value at 3, getting 4MHz 
f_OC = 16000000/(1(1 + 3)) = 4000000
Why can't be the TOP value set at 1?

user368: Because then you only have 1-bit PWM. And there aren't an awful lot of applications for 1-bit PWM.

18574: <p>The max PWM frequency that can be achieved with an Arduino is by using the PWM fast mode with the pre-scaler set at 1 and the TOP counter value at 3, getting 4MHz </p>

<p>f_OC = 16000000/(1(1 + 3)) = 4000000</p>

<p>Why can't be the TOP value set at 1?</p>
 368: <p>Because then you only have 1-bit PWM. And there aren't an awful lot of applications for 1-bit PWM.</p>
