Using rotary switch in embedded design can save board space and in same time be very intuitive. With knob turn you can change parameters, go through menu and do all sorts of things. But rotary switches aren’t low cost solution. Since most microcontrollers already have ADC integrated, why not replace it with simple potentiometer. This is what Claude Haridge suggests in his example.
There are several benefits of using potentiometer instead of rotary switch. First of all you only need one MUC pin. This already gives a chance to choose smaller micro. Also with potentiometer you dont have bouncing problem. Another benefit is that this is cheaper way. But you also loose some benefits of switch. First of all you loos detent feel of switching – hard to determine switching positions as you turn potentiometer. Another thing is that you need more sophisticated algorithm to read switch states. It is worth considering to use potentiometer in cheap solutions.