[Discuss] Parallel ports

[Hans Oeste]

No a /dev/parport0 didn't show.  But what was strange is that the first time
I ran the program there was no /dev/lp0.  The program bombed.  The second
time it was happy.  Very weird.  And /dev/lp0 magically appeared. So I used
dmesg to find the starting adress for the parallel port as it detected it,
changed the address in the program and recompiled.  Walla.  I'm getting
results when I test the programmer.  Not the ones I'd like but much better. 
Must be a wiring problem somewhere, so off to hunt that down.
 
Thanks guys.
 
Hans
 
-------Original Message-------
 
From: Rick Morris
Date: 09/27/06 19:59:51
To: discuss at vlug.org
Subject: Re: [Discuss] Parallel ports
 
I _think_ that you have to connect something like a printer to the parallel
port to get /dev/lp0 to show up, don't you? At least that's what it looks
like dmesg is saying on my system (kubuntu)
 
Is there a /dev/parport0? Can you use that?
 
What shows up in /proc/devices?
I show (among others)
  6 lp
  99 ppdev
 
which means they show up in /dev/ as
$ ls -l /dev/lp0
crw-rw---- 1 root lp 6, 0 2006-09-25 21:43 /dev/lp0
$ ls -l /dev/parport0
crw-rw---- 1 root lp 99, 0 2006-09-25 21:43 /dev/parport0
 
You can always create lp0 yourself,
$ mknod /dev/lp0 c 6 0
 
I've yet to get udev to create anything the way I want (or perhaps expect is
more accurate!).
 
Rick Morris
 
On Wednesday 27 September 2006 17:37, Hans Oeste wrote:
> I've built a parrallel port programmer for a small eeprom type chip.
> Unfortunately the machine I'm trying to run the software on, which is
Linux
> software, seems to have a bum parallel port.  One of the signal lines
> appears to be dead.
>
> So I've tried to run the software on several laptops;  an IBM T42 and a
> Compaq EVO N610.  .dmesg states that a parrallel port exists, but under
> /dev there is no lp0 generated by udev.  I have also gone out and bought a
> PCI card with a parallel port on it to have the same thing happen.  No
> /dev/lp0. Unfortunately the software, written in 2004 has hardcoded port
> address assignments, although those are easy to change, at first glance
and
> then a recompile to sort that part out.  It also appears to require access
> to lp0 or the programmer software dies very indignantly.
>
> Has anyone any suggestions to do with generating a /dev/lp0?
>
> Hans-Peter Oeste
> VE7OES
>
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