Based on the feedback I got, I had an idea to derive an interface that can plug an Arduino Shield or an Arduino Uno into the Apple II bus using a 82C55 peripheral interface chip. By soldering stackable headers into the Apple II card, an Arduino Uno can be plugged into the back of the card, and shields can be plugged into the front of the card. There are resistors between the 82C55 and the Arduino pins to protect the Apple II and allow the transactions to be inputs or outputs. You can find the card at
http://www.github.com/profdc9/Apple2Shield
It should be a fun card for anyone who wants to experiment with interfacing to an Apple II.
Dan
Great stuff Dan, keep it coming!
Alex
Arduino is a great prototyping platform. This provides a pretty excellent way to design some neat stuff for the Apple II.