Hi,
I can help a bit here.
I have a nice little "logic analyser" display that works from fifo's.
It would not take much to make this use the parallel port.
I can package it all up for you if you wish.
It does use QT1.44 so you'll have to get that from <www.troll.no>
Regards
Phil
"Estabridis, Janet P" wrote:
>
> Hi Fulko,
> Are you saying you want to check these bits every 1 msec and if there is a
> change then record the time and the change ?
>
> If so, yes, you will be able to do this quite easily with rt-linux. You can
> set up a periodic task that will read the parallel port every 1msec and then
> check the bits and do whatever you need to do. If this is all that is going
> on you'll have no trouble. The rt task could communicate via fifo or shared
> memory to an application and the application could print status information
> to the screen along with writing the required data and time to disk. Even
> if there is a flood of changes, the fifo can be set up large enough (or
> shared memory) to handle this.
>
> If you need some example code, I have something simple that I hacked to
> toggle bits on the parallel port to see the accuracy of the real time timer
> functions.
>
> Let me know --
>
> Janet Estabridis
> Electrical Engineer
> NAWC Code 473E00D
> China Lake, CA 93555
> [EMAIL PROTECTED]
> (760) 939-2896 FAX (760) 939 -3075
>
> > -----Original Message-----
> > From: Fulko van Westrenen [SMTP:[EMAIL PROTECTED]]
> > Sent: Wednesday, September 15, 1999 6:38 AM
> > To: [EMAIL PROTECTED]
> > Subject: [rtl] data-logging through parallel port
> >
> > Hello,
> >
> > I have a problem that looks to me like a FAQ so I would like
> > to know if someone knows the answer before I learn
> > by extensive trial and error.
> >
> > For an experiment I have to read at least two signals (TTL),
> > preferably more but eight at most, with <=1ms accuracy (the 1ms
> > is essential, missing an event is ``unacceptable'').
> > When the signal goes low (or high when that is easier), this
> > event must be written to disk together with the time.
> > The signal-rate is about 2Hz and one experiment lasts from 1-4 hours.
> >
> > It looks to me that the parallel port on a PC together with rtlinux
> > can do the job but I'm not sure. Does someone have some experience
> > with this and knows how it can be done?
> >
> > Thank you very much for your time and for any information you
> > can give me.
> >
> > Sincerely,
> >
> > Fulko
> >
> > --
> > Fulko van Westrenen
> > email: [EMAIL PROTECTED]
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