Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!sunybcs!planck!aardvark!westley
From: westley@aardvark.uucp (Terry J. Westley)
Newsgroups: comp.realtime
Subject: Re: Port bit twiddling for profiling (Was :Cross profiling tools for VxWorks?)
Message-ID: <1989Dec7.173534.27769@planck.uucp>
Date: 7 Dec 89 17:35:34 GMT
References: <DOVE.89Nov25105609@peach.uucp> <41649@srcsip.UUCP>
Sender: news@planck.uucp (Usenet News)
Reply-To: westley%hercules@planck.UUCP (Terry J. Westley)
Distribution: comp
Organization: Calspan Corporation ATC  Buffalo, NY
Lines: 22

In article <41649@srcsip.UUCP> sbrandt@src.honeywell.com (Scott Brandt) writes:

>  I used a very primitive yet 
>extremely effective trick to monitor process times etc.  What I did was
>have my various processes toggle bits on a data port at different places
>in their execution.  I then connected an oscilloscope to the data lines
>and watched my processes execute and interact.

Effective variations of this I have used are:

1) Toggle several bits in one or more ports and use a logic analyzer to
   see what is happening.  This also allows you to see a stream of data
   over a period of time (so would a storage scope with multiple channels).

2) Output a different D/A level for each point in the code when you have
   D/As, but no parallel ports (or no logic analyzer).


Terry J. Westley
Arvin/Calspan Advanced Technology Center
P.O. Box 400, Buffalo, NY 14225
planck!hercules!westley@cs.buffalo.edu