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Comment by downvotemyjokes | Hacker News Reader

I'd wager the device hanging off the PCIe bus looks very little like a traditional parallel port to the CPU. Notice the modes supported by the device don't mention 'RAW', and a number of reviews bitch about ECP not working.

Just because it is on pcie doesn't mean it isn't just emulating the most frequently used parts of a parallel port.

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I have successfully used a StarTech PCIe parallel port adapter card to interface with a stepper motor controller board, and I'm able to run CNC machining operations from LinuxCNC. It works fine in EPP mode (communicating bi-directionally).

The parallel port is actually very cool. You can take a high-end Linux machine and add the parallel port as a low latency GPIO interface with 25 pins. It can be used to control LEDs, motors, etc, and can also be used to receive sensor data, etc.

What is 'RAW' mode? I think you are referring to a legacy TCP/IP network printing protocol also known as "Port 9100." I'm not sure that's relevant to parallel ports?

By 'RAW', I mean being able to drive the port by poking at 0x378 in a highly controlled manner. (Not terribly uncommon when the hardware in the article was originally released)

0x378 is probably routed to the onboard LPT by the BIOS.

However, I wouldn't be surprised if those PCI cards used the same IO port protocol, only at some different address assigned in the standard way with PCI BARs.

This has been my experience when trying to interface with some legacy LPT stuff, much of the software of the era is basically hard coded to do that and won't play well with (or sometimes even recognise) the PCIe add on ports. YMMV, clearly.

My first PC had the parallel and serial ports connected to an isa card instead of the motherboard, I don't immediately see why a pci version would be any different.

This product may be shit, but the concept is sound. There is a direct compatibility line from pcie all the way back to isa, so it is in theory possible to build pcie peripherals that will work in dos provided your bios supports this.

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