Driving Heavy Duty PMDC Motors

It may look easy, but driving heavy duty PMDC motors from microcontrollers isn't straightforward! PWMing to speed control, will required that the MOSFET are 'cleanly' driven off and on. That can be easily done with TC4429 (or its brethren).

Since a microcontroller is usually connected to multiple other peripherals (like displays, sensors, communication ICs) and PWM heavy loads is inherently noisy, it makes sense to opto-couple the microcontroller from the power circuitry driving the motor using f.e. here a 4N35.