Re: Parallel port inactive

[Ray <rehenry-at-up.net>]

On Thu, 29 Mar 2001, Wallace wrote:

> Hello,  I have just set up EMC on a 486Dx33 with Redhat 5.2 and the
> associated RTlinux patch.  I have also been able to get it to run using the
> steppermod.o and minimillio.  The problem that I am having is that although
> I can get it out of estop and jog the axis I cannot get any activity on the
> parallel port.  I have an oscilloscope set up to read the port pins and they
> just stay at +5V.  The port is set up at 0x378.  Any suggestions would be
> helpful.
> 
>  I also wouldn't recommend this slow of a processor for more than getting
> set up experience, it can just run xemc but is not even usable with tkemc
> (well unless you can wait 30 sec for the mouse to move)

Wallace

Welcome and congratulations on getting the install successfully.  

You might try running a little script that is in the emc/tcl/scripts
directory.  It is called IO_Exercise.  It must be run from the emc
directory but can stand alone.  For this test, don't run the EMC at the
same time.  The command would be

cd usr/local/***/emc (replace *** with whatever for your machine)
tcl/scripts/IO_Exercise.tcl

and you should see a wish window with several buttons and labels.

Set the address to show to 378 and the address to change to the same
and then click some set pin buttons on the right and you will see
the number above those buttons change to a new value.  Press number set
and you should see the lamps change on the left side of the window. 

If no change, the parport is dead or not at that address.  If the lights
change but you see no change on the scope, then you need pull up or pull
down resistors or an external 5 volt supply.  For slow tests like
IO_Exercise, the scope is not the best instrument to use.  A multimeter may
be easier to read and if all else fails, you can use the ohms scale and
watch for an npn junction attempting to short a pin to ground.

IO_Exercise can also be used to watch for signals into the parport by
setting the value to 379.  You can also use IO_show in the same directory.

Hope this helps.  

Ray