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I found out about the CNC thing recently while trying to get a hobbyist CNC machine set up. My immediate reaction was "Parallel ports? What is this, 1985?" T

I found out about the CNC thing recently while trying to get a hobbyist CNC machine set up. My immediate reaction was "Parallel ports? What is this, 1985?" Turns out, there isn't really any getting around it. It's parallel port or GTFO. This is how I also learned that dirt-cheap PC motherboards still have parallel ports built in. The higher-end ones generally don't.

vibrolax 10y ago
It's not quite GTFO, but you do have to spend a lot more than the $15 it costs for an opto isolated parallel port to stepper interface board. My celeron j1900 does about 20k steps/second with low jitter on LinuxCNC
speeder 10y ago
My recently purchased ASRock Z97 Extreme4 has a Serial port header... I am here thinking what sort of thing I should build and hook up to it, just because I can
- exDM69 10y ago
  Yeah, I was surprised to find out a serial connector in my brand new (2015) motherboard. The previous motherboard I had didn't have headers for serial although there probably was one or more hidden on the board. You could plug in a VT10x or a similar dumb terminal in your brand new PC :)
13of40 10y ago
You can get a PCIe bus parallel card on Amazon for about $10 or $15. I've got one I use for programming an older FPGA board.
- cnvogel 10y ago
  Oh, yes. The great Xilinx Parallel Cable III. Still works a treat!
- throwaway7767 10y ago
  Just FYI, you can now get chinese knock-offs of the USB programmer for about the same price off eBay. They're faster than the parallel cable, and they work extremely well.
abakker 10y ago
Get a smooth stepper. The Ethernet one works great. I too ran into the issue with parallel ports, and basically, they aren't worth it. The timing is bad, and on most computers I've encountered, there's enough noise on the port that eventually it messes up a project at some critical part and convinces you that parallel ports suck. Better to have a board designed for specific pulse timing than counting on the average CPU to be consistent.
shabble 10y ago
If I recall from (maybe?) the linuxCNC forums, it's also pretty crucial to ensure your motherboard has a suitable chipset if you want to do soft-steppers. I think the reason is that some boards have various non-maskable system interrupts that will play hell with your timing if you get the wrong board. grbl or similar (Machinekit on a beaglebone) seem like reasonable alternatives for motion control, but I'd prefer the flexibility that having a full PC gives you...just without needing a whole PC (and probably needing a few PCI parallel expanders to handle all teh other GPIO you need)

vibrolax 10y ago

It's not quite GTFO, but you do have to spend a lot more than the $15 it costs for an opto isolated parallel port to stepper interface board. My celeron j1900 does about 20k steps/second with low jitter on LinuxCNC

speeder 10y ago

My recently purchased ASRock Z97 Extreme4 has a Serial port header... I am here thinking what sort of thing I should build and hook up to it, just because I can

exDM69 10y ago
Yeah, I was surprised to find out a serial connector in my brand new (2015) motherboard. The previous motherboard I had didn't have headers for serial although there probably was one or more hidden on the board. You could plug in a VT10x or a similar dumb terminal in your brand new PC :)

13of40 10y ago

You can get a PCIe bus parallel card on Amazon for about $10 or $15. I've got one I use for programming an older FPGA board.

cnvogel 10y ago
Oh, yes. The great Xilinx Parallel Cable III. Still works a treat!
throwaway7767 10y ago
Just FYI, you can now get chinese knock-offs of the USB programmer for about the same price off eBay. They're faster than the parallel cable, and they work extremely well.

abakker 10y ago

Get a smooth stepper. The Ethernet one works great. I too ran into the issue with parallel ports, and basically, they aren't worth it. The timing is bad, and on most computers I've encountered, there's enough noise on the port that eventually it messes up a project at some critical part and convinces you that parallel ports suck. Better to have a board designed for specific pulse timing than counting on the average CPU to be consistent.

shabble 10y ago

If I recall from (maybe?) the linuxCNC forums, it's also pretty crucial to ensure your motherboard has a suitable chipset if you want to do soft-steppers. I think the reason is that some boards have various non-maskable system interrupts that will play hell with your timing if you get the wrong board. grbl or similar (Machinekit on a beaglebone) seem like reasonable alternatives for motion control, but I'd prefer the flexibility that having a full PC gives you...just without needing a whole PC (and probably needing a few PCI parallel expanders to handle all teh other GPIO you need)