Prototype card and info needed for project

[Michael Spangler <spangler@gorge.net>]

I'm attempting to build a digital I/O card to run on an apple II, using
either an 8255 or a 6821 chip. An Apple II makes a considerably more
flexible controller than a Basic Stamp, and it can store its data on
disk for later transfer to another computer.

However, I need a prototype card for the A2 slot, and some details
about the electronics of connecting the 8255 to the bus. The card can
be memory mapped, as I don't need any ROM routines. The 16 bytes per
slot between C900 and C100 should be enough. I can see how to decode
the address lines, but do I use the device select or the slot select
pins, both, or something else?  

Does anyone know a source of prototype cards for the Apple II?

Does anyone know the details of interfacing this sort of card? Or where
the info can be found?


Thank you;
Mike

spangler@gorge.net