When driving power MOSFET from a microcontroller pin, is there a need for protection?
Yes! I speak here of experience. I blew up two micro controller ports because I did not do that. One switched twice before it went. I was driving a relay and after the ports blew I checked about ten times if my protection diode was the right way around. It was correct and still my ports died. A zener diode is expensive. Much cheaper is an RC circuit. I have been 'naughty' as I put the capacitor direct over the output pin. Thus the controller has to drive a rather high capacitive load. The pull-down resistor is because at start-up the I/O pin is floating and I want the FET to be guaranteed off.