USB also provides enough power to light a bright LED. There was no power on a printer port, though people would steal power by setting a lot of pins high and ho

USB also provides enough power to light a bright LED. There was no power on a printer port, though people would steal power by setting a lot of pins high and hoping for the best. I think I'd just spend the $2.40 and use an AT90USB82 instead. It has USB built in so you don't have to wrestle with software USB. I've done software USB on an Atmel and getting 98% of the way there is easy, but I never really trusted the end result. On the down side, it doesn't come in a DIP package, but you could use any little breakout carrier card to get to the pins. On the plus side you'd have a couple dozen pins to play with.