Or you could use simulation, Proteus, Oshonsoft etc. You draw your circuit diagram in the application and this creates a model in which the simulator allows you do do all your single stepping, variable monitoring, breakpointing etc. etc. The downside is cost and whatever imperfections are in the simulator, the upside is pretty good and will over a period recover some or all of that cost. A short list of the positives - no development system to buy, freedom to move between microcontroller families, almost instant circuit changes, cost savings on components (you only buy the bits you need). Simulation is built into Microchip's IDE, but its not visual and realy not intended for ... well now I come to think of it, anybody (IMO Microchip make good components and terrible PC software). BTW the new Java based ide, MPLABX is even worse. Personally I use Proteus, it can do mad things like breakpoint on a voltage level. Most simulators will also allow you to produce a PCB. Hope that helps George