Re: Changing Parallel Port Pins

[Rick Mann <rmann-at-latencyzero.com>]

on 9/20/02 8:12 PM, Jon Elson at elson-at-pico-systems.com wrote:

> The ini file, at the end, has the specifications for all the auxilliary I/O
> (machine on/off,
> spindle, coolant, etc.)  The bits are specified as an index, so 0 means the
> first bit,
> 1 means the 2nd bit, etc.  Sensing of the Estop input is there, too.  Look at
> the end
> of the file, in a section called [EMCIO].  One standard setup has
> ESTOP_WRITE_INDEX = 10
> which puts the estop output signal on the 3rd control output pin (0..7 are the
> standard
> data lines).
> If you really need to have 3 separate outputs, you will need to hack one of
> the
> routines in /usr/local/emc/src/emcio such as bridgeportaux.cc
> You will see that it sets a bit as specified by the parameter
> ESTOP_WRITE_INDEX
> to a state set by ESTOP_WRITE_POLARITY for going to ESTOP, and to the
> opposite polarity for coming out of ESTOP.  3 calls to extDioWrite with
> appropriate
> parameters should make 3 bits on the parallel port change state.  (Note that
> the program
> monitors the state of these bits, so if the specified bit diesn't change to
> the right state,
> it will start writing error messages dozens of times a second.)

Thanks for the info, Jon. However, I'm afraid I'm still not finding what I
need.

I'm using a stepper motor driver called a FET-3, from StepperWorld.com. It
uses pins 14, 16 and 17 on the parallel port as axis enable signals. I'm not
sure if they all need to be high, low, or some combination to enable each
axis, but there is one pin for each of three axes.

For simplicity's sake, I'm happy if I can find a way to force all these pins
either high, low, or some combination, in order to enable my motors.
Interestingly, the X-axis (pin 14) works as-is with the Generic EMC run
script and .ini file.

If I need to modify some code, could someone please give me the basic steps
for building such a mod? I've installed the BDI 2.16 install (although I
think the version reported in the login window is 2.14).

Thanks in advance for any help!
 
-- 
Rick