What Are PWM Pins? The Arduino Mega's PWM pins are digital output pins located on D2 to D13 and D44 to D46, coming to a total of 15.

[Runtimemicro] has the answer, at least if you are writing PWM code for the Arduino. Their free application lets you set a few parameters, visually see the results, and then generates code for you.

It requires two pins to control the direction and one pulse width modulation (PWM) pin to control the speed. The pins are passed via constructor and the names should be self-explanatory.