Re: Hardware Project

[david@uow.edu.au (David Wilson)]

Paul Schultz <pschultz@med.wayne.edu> writes:
>It's great to see someone working on an Apple II hardware project!

All this discussion about Apple II cards has made me revisit an idea I had
in the past to simplify designing cards for the A2.

Most any card you design with on-board ROM needs to decode all three selects
(DEVSEL, IOSEL and IOSTB) and generate chip selects for ROM, devices and the
data bus buffer. This tends to take quite a few LSTTL chips. My idea is to
replace these with a single PAL/GAL (plus an 8 input NAND gate) to take care
of all this (including the CFFF disable function). It will also allow for the
use of RAM instead of ROM as this makes code development much easier.

Any thoughts on this would be appreciated.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia  david@uow.edu.au