Path: utzoo!attcan!uunet!jarthur!petunia!ucselx!crash!pro-sol.cts.com!mdavis
From: mdavis@pro-sol.cts.com (Morgan Davis)
Newsgroups: comp.sys.apple2
Subject: Hardware Project for II+
Message-ID: <2850@crash.cts.com>
Date: 28 May 90 06:56:08 GMT
Sender: root@crash.cts.com
Lines: 28

Hardware hackers, I have a project for you!  This is really neat.

If you've ever tried to write routines on the II+ that require precise
timing, you know you're in for trouble.  Especially now with a proliferation
of faster CPU's and speed-up cards that work in the Apple II+, the problem
is even worse.  On every other Apple, you can read the vertical blanking
signal (which cycles every 60th second) and synchronize timing loops to that.
On the II+, there is no such register you can read.

I started to think that the normally useless cassette tape ports could be
used.  If you could plug a little unit into the tape ports, one which
generated a 60Hz signal, you could read the tape's input register,
then the timing problem would be solved.

The ports provide power for a simple circuit to operate.  Parts needed would
probably be some regular phono input jacks (and interconnect), a small PC
board, an oscillating IC, and a few caps.  I'm not an EE graduate, so I'm
pretty ignorant about electronics.  However, it seems that such a project
would be quite simple to make.

Any electronics nuts out there who might have an idea on a schematic or basic
layout (and parts list) for such a project?

--Morgan

UUCP: crash!pnet01!pro-sol!mdavis		ProLine:  mdavis@pro-sol
ARPA: crash!pnet01!pro-sol!mdavis@nosc.mil	MCI Mail: 137-6036
INET: mdavis@pro-sol.cts.com			America Online, BIX: mdavis