I keep seeing various posts mentioning Proteus; not really familiar with it. Is this something that has become defacto popular the last year with the freaks? Is it a good deal (ie: freeware, or limited freeware). Maybe I'm missing out on the fun. It seems like simulating might be useful at times, but I've seen a lot of poor processor simulations in the past, where critical peripheral parameters were not 100% modeled correctly. I've been more on the LTspice train, riding it for circuit simulation & watching the scope traces roll by.