parallel port access on Linux

I was easily able to use the parallel port from Squeak in Windows with
the DLL and change set from the IOST package at
http://www.smalltalking.net/Goodies/Squeak/

Some people, however, are asking for my help getting this to work on a
Linux machine. There was a thread here in April 15 of last year with
some code posted by Thimon and there have been similar threads in the
past including some advice by Ned Konz. Since there are many
alternatives, all require at least some work and none which is obvious
superior to the others, it would be great if people could share their
experiences and/or insights about this.

-- Jecel

I have some C++ code that works under Linux, but I only used that to
drive a couple of relays attached to the parallel port.
http://www.cdegroot.com/photo-linuxdr/ - maybe not exactly what you're
looking for, but it might just contain enough hints :)

On 2/3/06, Jecel Assumpcao Jr <[hidden email]> wrote:

Jecel Assumpcao Jr a écrit :
Yes, we made some work on parallel port in order to link Squeak to
robotic modules. Look at our SqueakBot project here :
http://www.iutc3.unicaen.fr/serge/SqueakBot


--                                                         oooo
Dr. Serge Stinckwich                                     OOOOOOOO
Université de Caen>CNRS UMR 6072>GREYC>MAD               OOESUGOO
http://purl.org/net/SergeStinckwich                       oooooo
Smalltalkers do: [:it | All with: Class, (And love: it)]   \  /
                                                             ##

Cees De Groot wrote on Fri, 3 Feb 2006 19:28:45 +0100
> I have some C++ code that works under Linux, but I only used that to
> drive a couple of relays attached to the parallel port.
> http://www.cdegroot.com/photo-linuxdr/ - maybe not exactly what you're
> looking for, but it might just contain enough hints :)

Cute, thanks for sharing this!

This approach (run as root, code i/o instructions in assembly) could
work if I used Exupery, but that requires a special VM and if I am going
to have that I might as well add some primitives or something like that.

For just setting the pins on the parallel port to some value it seems
that normal file operations on /dev/lp0 would be good enough:
http://people.redhat.com/twaugh/parport/html/ppdev.html

For a more detailed control we would need the ioctl() system call with
/dev/parport0 and that is something that, as far as I know, Squeak can't
do. Is this planned as part of the great file reform?

-- Jecel

Serge Stinckwich wrote on Fri, 03 Feb 2006 20:54:58 +0100
> Yes, we made some work on parallel port in order to link Squeak to
> robotic modules. Look at our SqueakBot project here :
> http://www.iutc3.unicaen.fr/serge/SqueakBot

That looks perfect, thanks! I will forward this to the group at the
University of São Paulo doing this work and since what they are doing is
so similar to this I think they will be doubly pleased to see this.

-- Jecel

I wrote:
> Serge Stinckwich wrote on Fri, 03 Feb 2006 20:54:58 +0100
> > Yes, we made some work on parallel port in order to link Squeak to
> > robotic modules. Look at our SqueakBot project here :
> > http://www.iutc3.unicaen.fr/serge/SqueakBot
>
> That looks perfect, thanks! I will forward this to the group at the
> University of São Paulo doing this work and since what they are doing is
> so similar to this I think they will be doubly pleased to see this.

The image/changes pair segfaults for me in

2038523660 ParallelPortUnix>readData
2038523568 Moebus>highSDA
2038523476 I2CHandler>start
2038523384 I2CHandler>readFrom:
2038523292 Smec>statusByte
2038523200 Smec>status
2038523016 SmecMorph>step
2038522188 Morph>stepAt:
[....]

while trying to start up, which isn't surprising given that I don't have
"parallelplugin" which it tried to call. The sources only include .mcz
packages, so it isn't very obvious to me how to get that.

-- Jecel

Linux is so evil that I can't access my parallel port in any way from
any program. -- and it never gives an error message when I try to print
a test-page from the KDE utilities...


--
Don't let your schoolwork get in the way of your learning.

http://users.rcn.com/alangrimes/
(for some reason Charleston SC is back in my signature... I hope you
don't learn why...)

Check the section SqueakBot-Hardware
(http://www.squeaksource.com/SqueakBot as mentionned by Serge) which
implements the parallel port access under linux and windows
(ParallelPortUnix and ParallelPortWin). We should extract this part of
squeakbot and make a release of it since it would be of interest for
general use, so if you have some times, feel free to build a parallel
port squeakmap package with all these materials !

You will also need the tarball containing the C code (in fact, it
should be translated in a squeaky fashion as a ParallelPortPlugin
class which would avoid to distribute the tarball).

All this work is already tested ok both for linux and windows
(IOSTSqueak needed for windows)...

Have fun :-)

Samir

Samir Saidani wrote on Sat, 04 Feb 2006 00:07:13 +0100
> Check the section SqueakBot-Hardware
> (http://www.squeaksource.com/SqueakBot as mentionned by Serge) which
> implements the parallel port access under linux and windows
> (ParallelPortUnix and ParallelPortWin). We should extract this part of
> squeakbot and make a release of it since it would be of interest for
> general use, so if you have some times, feel free to build a parallel
> port squeakmap package with all these materials !

This is all included in the image/changes I had downloaded from the page
Serge indicated.
 
> You will also need the tarball containing the C code (in fact, it
> should be translated in a squeaky fashion as a ParallelPortPlugin
> class which would avoid to distribute the tarball).

I found it attached to an email to this list from April 15 of 2005.
After getting the needed uncompression tool (Gentoo has a wider
selection of tools than RiscOS ;-) and compiling it, copying the .so
file to where the squeak binary is I still get the same result. Given
that this is via FFI shouldn't the unmodified VM be able to load this?
 
> All this work is already tested ok both for linux and windows
> (IOSTSqueak needed for windows)...

Great!

> [parallelplugin.tgz]

Ah - thanks for sending this again. I hadn't noticed it until I was
replying to you (Celeste is a bit too subtle sometimes).

-- Jecel

Jecel Assumpcao Jr <[hidden email]> writes:

Ok but the squeaksource one is probably the latest up-to-date code,
don't know about the image you downloaded...


>> You will also need the tarball containing the C code (in fact, it
>> should be translated in a squeaky fashion as a ParallelPortPlugin
>> class which would avoid to distribute the tarball).
>
> I found it attached to an email to this list from April 15 of 2005.
> After getting the needed uncompression tool (Gentoo has a wider
> selection of tools than RiscOS ;-) and compiling it, copying the .so
> file to where the squeak binary is I still get the same result. Given
> that this is via FFI shouldn't the unmodified VM be able to load this?

Same comment, things has maybe changed since that date, I've sent you
the last up-to-date code.

Cheers,
Samir

Samir Saidani wrote on Sat, 04 Feb 2006 01:56:55 +0100
> Same comment, things has maybe changed since that date, I've sent you
> the last up-to-date code.

I had tried this version with the same result, but then noticed that a
previously installed VM on my machine (3.2-5) had the files
SqueakFFIPrims.so and SqueakFFIPrims.la in the executables directory
while the current one (3.7-7) doesn't. Copying the file you sent to the
old directory and running that I no longer got the segment fault. I
still got two errors "external callout not available" since it is
looking for the file "libffi.so.1" which isn't available on my machine.

So the image was ok and the parallelplugin probably is ok as well but my
Linux Squeak isn't configured correctly for FFI. That, unfortunately,
seems to be the default.

-- Jecel