If you’ve never worked with CPLDs or FPGAs, it can be quite a steep learning curve to get started. Why bother? Programmable logic lets you build real circuits on silicon instead of simulating them with a microprocessor. For example, suppose you want to build a super alarm system with 100 inputs. With a microprocessor, you’d have to examine all the inputs (probably in groups of 8 or 16 or 32) which means while you are examining one set of inputs, the others aren’t being examined. Sure, you could use interrupts, but even then, you’ll only really “see” one input at a time and respond to it.
With programmable logic, you can literally look at 100 inputs in parallel and take action on them rapidly. That’s because a programmable logic chip produces dedicated hardware that you can reconfigure, not a software simulation.
A while back I put together for the local ham radio club about how to get started with programmable logic. It isn’t very in depth (but there are some links to tutorials in it), but it is a good starting point.
By the way, I’m using the excellent
to publish these slides here. Pretty cool, huh?