I have used toggling the parallel port bits to check out my ISR timing and
generally get a feel for rt-linux when I started out. Enclosed are some
files that should help. Essentially the parallel port is i/o mapped and you
need to use ioperm to allow yourself to write and read from the port
using outb and inb commands.
I am enclosing my real-time task and my non-real time application that I
used to prove some concepts before selecting LINUX with rt-extensions for my
current project.
IN THE RT process you'll find -- the structure you'll need -- rt_task_init(
... ) is the key. I changed the time between calls to the function and
toggled a bit on the parallel port to get an idea of how much jitter there
was. Something like this should work nice for you to check the parallel
port.
<<rt_process30Hz.c>>
These next ones I was using the FIFO's to communicate between the rt-task (
being executed @ 30 Hz ) and the application which was being told to "record
data" and "stop recording" data over the ethernet. So, it may not make too
much sense. The idea is that the rt task was communicating with the
application via the fifos.
<<rt_process30HzFifo.c>> <<dataRecFifoV2.c>>
I'm sure there are other people out there that have more eloquent code.
This is all very quick and dirty to prove the concept. My other stuff that
I'm developing is a bit neater, but has lots of stuff that is unnecessary.
I really am no expert with this. What I can tell you is it is easy to get
up and running. I also knew Pascal before I knew C and it isn't too
different.
Janet
> -----Original Message-----
> From: [EMAIL PROTECTED] [SMTP:[EMAIL PROTECTED]]
> Sent: Thursday, November 04, 1999 12:13 AM
> To: [EMAIL PROTECTED]
> Cc: [EMAIL PROTECTED]
> Subject: Re: [rtl] Control through PARAL.LEL port.
>
>
> > I need to control a external circuit though the paral.lel port
> > Anyone known where are there any documentation
> > and exambles about this subject.
>
> E.g.
> http://www.hut.fi/Misc/Electronics/circuits/parallel_output.html
>
> Gabor
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> ----
> For more information on Real-Time Linux see:
> http://www.rtlinux.org/~rtlinux/
rt_process30Hz.c
rt_process30HzFifo.c
dataRecFifoV2.c
