External Control Lines

I have my first application in PBP fairly well blocked out and I'm coming to the point where I have to decide on what external devices I'm going to have to use to get the desired functions.

The point being, is it more cost/time/effort effective to use a couple of external devices to read my switch inputs and store my control line outputs or should I just use the largest PIC that will do the job internally.

If I use external devices, I understand that there are several different methods or formats that can be used (I2C, serial CMOS shift registers, etc.). Is there a bonehead simple place to go to read the strengths and weaknesses of each?

Just for information, there will be about a dozen inputs and a couple of dozen outputs to do the job.

Jim

A single-chip solution is (at least in my opinion) pretty much always the best
way to go. With that many I/O-pin requirements, a PIC with enough I/O will
for sure cut down on your parts count & finished PCB size.