Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!mit-eddie!mit-amt!snorkelwacker!spdcc!merk!xylogics!cloud9!jjmhome!m2c!wpi!greyelf
From: greyelf@wpi.wpi.edu (Michael J Pender)
Newsgroups: comp.sys.apple
Subject: Re: Oscilloscopes
Keywords: oscilloscopes, tektronix
Message-ID: <6208@wpi.wpi.edu>
Date: 12 Dec 89 03:45:28 GMT
References: <0.net.apple@pro-lep> <5862@wpi.wpi.edu> <1935@psuhcx.psu.edu>
Reply-To: greyelf@wpi.wpi.edu (Michael J Pender)
Organization: Worcester Polytechnic Institute, Worcester ,MA
Lines: 41

In article <1935@psuhcx.psu.edu> doug@psuhcx.psu.edu (Doug Hughes) writes:
>
>I remember that last spring (or so) someone had posted to the net about
>making an Apple II into an oscilloscope. I don't remember who it was, but
>at that time he said he was very busy preparing his Thesis, but had the
>schematics for doing it on his mac or something. I don't even know if he's
>around anymore. I used to have his address and wrote to him a few times
>about it. But he was always too busy. He said that it made a fair oscilloscope
>too. I'd love to get my hands on those plans!! Anybody else out there (
>or this person if he's still around) have plans like these available?
>I'm sure people would love to see them, and even pay.
>	Doug Hughes
>	doug@hcx.psu.edu
>	{mcvax,gatech,rutgers}!psuvax1!psuhcx!doug
> 

I ended up buying a wonderful Hewlett Packard scope from the school
here instead, so I'm all set in that department.  The reason I'm posting
is in response to your request for info on making an apple into an
oscilloscope.  An apple can easily be made to act like a digital
oscilloscope.  For a class demonstration one of my professors built one
on Friday using an 8085, an 8 bit d to a, and an 8 bit a to d convertor.

Most a to d convertors aren't fast enough for high speed signals.  If
one figures they need about 20 points/cycle with a 100 KHz (fast)
a to d convertor the chip could start to lose out above 5 KHz.

This is not bad however.  

Mostly the computer is more useful at lower speeds, where the scope shows a 
waveform as a slowly moving dot or line, and the apple can instead 
send the same signal back to the scope at a much higher speed.

I'm kind of busy now (middle of finals, I'm about to be a senior), but
if there's interest I'll try to find some way to post hardware 
specs and software for a 6502.

---
Michael J Pender Jr  Box 1942 c/o W.P.I.        ... (Mankind) has already 
greyelf@wpi.bitnet   100 Institute Rd.          used its last chance.
greyelf@wpi.wpi.edu  Worcester, Ma 01609               - Gen. MacArthur