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From: Andrew Cottrell <andspam DOT at DOT swiftdsl DOT dot DOT com DOT dot DOT au AT unknown DOT addr>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Thread Swithing Time in pth1.3.7?
Date: Thu, 12 Feb 2004 17:28:51 +1100
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To: djgpp AT delorie DOT com
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>I use osilliscope to measure the signal from parallel port and find
>that that the the time beteen rising edges is around 760 microseconds!
>To be honest, it is too large to use in a time-critical environment.

This is a very good result. Have a look at the parallel port spec and
the access times for the interface and you will find that the timing
is all to do with the access time of the ic.

A better way is to use the PC timer tick and count the number of
itteractions per tick and then divide the numbers to get the time and
make sure you do this for a number of seconds to give a better
average.
 
And do NOT run the test under Windows as Windows steals time and CPU
resources even if you are running in full screen.


Andrew