How to create some feedback to LinuxCNC over parallel port.

[Langdon]

I have a PMDX-122 CNC breakout board that is connected to a PC running LinuxCNC on Debian via a parallel port and parallel port card.

The PC, breakout board, cable, and parallel port card work properly.

I intend to design a circuit so the E-Stop button pauses the current LinuxCNC job when pressed, and resumes the job when released.

How can I configure LinuxCNC to pause when it receives a signal on one of the parallel port inputs (probably pin 10-15)?

If LinuxCNC is not capable of doing this, what software do you recommend?

I can run Windows 7 32-bit on my PC.
Mach 3 should work on Windows 7 32-bit.
However, when I run Mach 3, the PC just turns off instantly and reboots.
I would like to avoid Mach 3 if at all possible.

[Langdon]

I intend to use parallel port pin 10 to transmit the E-Stop pause/resume signal to LinuxCNC.

Is that possible?

I also would like to wire up homing switches.

I can use pins 11, 12, 13, 15 to communicate with the PC.

Pin 10 is reserved for the E-Stop function built into the breakout board.

The breakout board is configured so the output buffers are output only (PC-to-driver) and are always on, regardless of the E-Stop button.

[Langdon]

https://www.pmdx.com/Doc/Archive/PMDX-122_Manual_111.pdf

[reboots]

LinuxCNC does have a pause/resume function. Input pins 11, 12, 13, and 15 should be accessible through HAL signals parport.0.pin-11-in ... parport.0.pin-15-in. The exact details for configuring one of these as pause/resume will depend on whether your estop button is momentary or latching, i.e. whether you need to include toggle logic in software.

Here's an example of someone's HAL config for an external pause/resume button through the parallel port:

https://forum.linuxcnc.org/forum/49-basic-configuration/29885-cycle-start-pause-resume-button

Unfortunately I am a novice at HAL configuration, and can't give you more specific details. I encourage you to ask on the LinuxCNC forum.

[Langdon]

The e-stop is latching.

It is not momentary.

[Langdon]

I want the voltage state of pin 10 on the parallel port to determine whether LinuxCNC is paused.

e.g. When pin 10 is HIGH, run the program/jog axis/home axis; when pin 10 is LOW, pause all actions.

It may be the other way around (pause when HIGH, run when LOW).

[Langdon]

I just tested it.

LinuxCNC should pause when pin 10 goes HIGH and resume when it goes LOW.