Apple II hardware design

From: A.R. Duell <>
Date: Mon Jun 23 21:51:06 1997

> > Maybe for you. I find it a lot easier to solder up a card (which has a
> > good chance of working first or second time...) than to write and debug
> > software. In all my recent projects the hardware (quite complex hardware
> > - 10's of chips) has taken a lot less time than the (minimal) software.
> Depends on your forte. Mine happens to be software. I'll bet I can

Agreed 100%. I happen to be like Steve Ciarcia - 'my favourite programming
language is solder'.

> write the software faster than you can solder the board. HOWEVER, I'll

I wouldn't bet on it.... I've been known to go from idea to working
prototype in < 1 day.

> also wager that you have a lot more flexibility since you can design in
> features to your hardware that I cannot program in to my software.

And if I'm allowed to use some of those Xilinx FPGA chips, I can even
design reconfigurable hardware that you can change by just downloading a
new file....


> > And is it that hard to design an address decoder? It's one chip these
> > days, probably 2 or 3 at the time the Apple 2 was 'current'
> Probably or you know for sure?

Well, lets see... Does anyone know when the 74LS68x series came out? Were
they around when the Apple ][ was current. PALs were sort-of current, and
I guess a 14L4 would be an ideal address decoder. That's one chip if I can
use a PAL or 2 if I can use a couple of 74LS68x's (to decode an entire 16
bit address bus)

If you insist I stick to 'classic' TTL then I'd want a 74LS133 13 input
NAND gate, and a couple of 74LS04 inverters. That would decode just about
any combination of 13 address lines. If you want all 16, then add a
74LS138 for a total of 4 chip max (and you might get away with only one
'04 if you're lucky.

> Sam

The gates in my computer are AND,OR and NOT, not Bill
Received on Mon Jun 23 1997 - 21:51:06 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:30:30 BST