Macintoshes...

From: Pete Turnbull <pete_at_dunnington.u-net.com>
Date: Wed Jun 24 19:52:09 1998

On Jun 24, 23:38, Tony Duell wrote:

> > > So, how easy is it to crock up a keyboard and mouse for either
machine?
> > > Can I modify IBM gear to fit the bill?

Not for the keyboard, it uses 8 data bits with no start/stop/parity bits
and a separate clock; XT keyboards use 8 data bits with 2 start bits, 1
make/break bit, and a stop bit; AT/PS2 keyboards use 1 start bit, 8 data
bits, 1 parity bit, 1 stop bit.

> > null modem enclosure). The keyboard is Mac proprietary.
>
> Yes, it's _strange_. 4 wires, +5V, Data, Clock, Ground. The mac end uses
> the shift register in a 6522, the keyboard end uses a microcontroller
> (8021?). Given a keyboard the protocol is probably hackable with a logic
> analyser (future project?),

Yes, it is an 8021. The protocol is in "Inside Macintosh", Vol. III
pp30-32. It's fairly simple, though it's bi-directional.

-- 
Pete						Peter Turnbull
						Dept. of Computer Science
						University of York
Received on Wed Jun 24 1998 - 19:52:09 BST

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