theres different aproaches for wat u want to do men, as far as i know pic12f883 has 4 I/O pins not fully sure about this u will have to look for the data sheet, u could make each one of the outputs send a different rate of frecuency or having just one output controlled by 3 inputs wich will tell the pic to execute a different frecuency in the output. U could have 1 Input, 1 Output and controll the input with an analog controller and have diferrent buttons for wich frecuency u want to use, or set of comands by conecting the other 2 pins different buttons u can make a macro, yes you can make a macro for ur 360 controller but it will only control 3 buttons if u use a pic so simple. Pretty much is up to wat u wanna do and the knowlege u have about programing. My advise is to download MPLAB and make ur own progrma for this ull only need like 5 instructions in assamble wich ull have to learn to use.