Parallel Port?
- Todd Zuercher
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I am just curious, why is EMC only able to use parallel port pins 1,14,16, and 17 only as outputs? The reason I ask is because we have sever older CNCs running some old DOS software that do use each of those pins as inputs for limit switches. It would make converting them to EMC a bit simpler if I didn't have to make my own cables to run them. It would also be nice to beable to devide the number of ins and outs on one port more evenly. (if I could have 8 of each on one port, then I could get by with one instead of two.)
Some specific parallel ports have open collector outputs, which can be forced low and the values read.
This is outside the p-port spec, and is not something that the EMC2 driver can afford to assume is safe.
It ought to be possible to change hal_parport to read those pins, if you want to.
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Be aware it only works on some parallel ports (hardware limitation) and the driver code has probably not received much testing in the years since it was put in. The comments in the code call it experimental. Please report back with your success/failure if you try it.
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- Todd Zuercher
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- Todd Zuercher
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- Todd Zuercher
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I made some slight modifications the parallel port tester in the wiki to work with X mode, so I could easily test the pins on the ports of the computer. Unfortunately the built in parallel port in this computer will not support the x mode, however the PCI one that I had will. I have another one of these on order. Once I have a second port then I will be able to do some testing on the machine.
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- Todd Zuercher
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