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PC Parallel Port emulation


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#1 jim

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Posted 14 February 2015 - 06:21 PM

How would one go about using the GPIO to emulate a typical PC Parallel port???
I am considering using the PCduino as a small CNC controller.


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#2 jim

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Posted 14 February 2015 - 06:21 PM

not easily. I've been playing with this too. 

I've actually been trying to fool the system into thinking it has a parallel port. 

This is the way I'm trying, so I can run EMC2. It;'s probably trivial for someone who has programming experience. 

Google "parport"    .
There may be other ways



#3 jim

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Posted 14 February 2015 - 06:21 PM

How about a USB->Printer Port adapter? They can be found for less then $10 if you look around - for example http://dx.com/p/usb-...e-adapter-27180

Although you could make the GPIO pins look like a parallel port it would be far simpler just to plug one of these in.



#4 jim

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Posted 14 February 2015 - 06:21 PM

I played with one of these a few years back. I found that lacked in speed. There was also a barrier between the device drivers for the adapter and the parallel port functionality of most cnc machine controller software, (Mach3, EMC2, etc.) 

My goals focus mainly on EMC2. This software runs on Linux. It has support mainly for interfacing the Linux Parport. There are other drivers available for industrial type PCI cards too. EMC will only let you run in what they call "Simulate Mode" when it detects that there is no Real Time kernel around. While operational, there will be no physical output of any kind. This is useful when designing your own machine because it allows you to simulate running Gcode on your machine with an operator interface and a GL rendered model of your machine running through the lines of Gcode.

This has been a long term goal of mine for a while. I am really determined to have a tablet style controller for my cnc equipment. I am defenitly NOT a programmer or electronics engineer. I am only a 40year old kid playing with his toys.

Anyways, I don't want to turn your PPort thread into a CNC thread. 

My best guess would be to grab the source for the Parport Linux and get it to cross compile after doing lots of tweaking to the IO section. 

What were you considering for your cnc software? It seems too that the Arduino had been proven to make a pretty good cnc controller. I think there's lots of 3D printers that use it. 

Is your concern based on having an existing stepper driver that has a 25pin interface?



#5 jim

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Posted 14 February 2015 - 06:22 PM

Actually,  I'm in the design phase of a 3 axis stepper driver right now,
so a 25pin Parallel port is NOT a necessity, just really need a means 
of interfacing CNC controller software output to the stepper driver hardware.

Making a 12" X 12" drill and route table for PCB fab....  Need the drilled
hole accuracy for doing Plated Thru Holes.

Seriously, the PCduino promises to be an awesome platform for CNC,
provided the interface issue can be solved.  

ANY help / ideas are appreciated.

Olmstw



#6 jim

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Posted 14 February 2015 - 06:22 PM

I think linuxcnc really could work, i have seen posts about getting xenomai realtime Patch working on A10, and seeing PcDuinoer's promise about kernel sources on github makes me even more positive. 
Im in the process of porting teacup 3D printer firmware to work on the pcduino, after that i'd happily cooperate with someone to get a linuxcnc HAL driver for gpio working. I have a 3 axis stepper hardware just waiting to get some work done smiley.gif



#7 jim

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Posted 14 February 2015 - 06:22 PM

If that source is being promised then I kinda feel like I'm wasting my time trying to pull out the configs. It seems to be a give take relationship between available images. XBMC has the Mali stuff working but wifi driver is broke. The shipped image doesn't show any signs of Mali. 

I think I'll start playing with getting LinuxCNC going in --enable-simulation mode. Of course I'll have to start with the XBMC image because of the GL.






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