Set up parallel port as input _ hardware

It is better to use the built in parallel port for inputs and the add on as outputs, this way even if the add on miss behaves = the machine will not move. If it fails to load as inputs the machine will move but the inputs will not work so the machine could crash, assuming the inputs are for limit switches.
The main reason for that is that most motherboards assign resources to add on cards automatically so the address might change at boot time, it did happen to me twice. This can be prevented in BIOS by setting the resources manually, but not all boards have that option.
And yes, most add ons will need pull up resistors on inputs.

Nordle wrote:

I made a machine configuration and checked the new parport in my hal configuration. When i short pin 2 for example to gnd the yellow indicator turns red for that pin. But does not turn back when i remove the connection. I do not understand how the parport works, does it need a pullup?

It might, it rather depends on the parport. And (unexpectedly) the mode it is configured in.

If your BIOS sees your parport, the configure it EPP. this shouldn't matter, but in some cases is increases current drive capacity. (Yes, I know, that makes no sense)

Does the pin ever come back?

You can typically change the state of a parallel port pin by connecting it to one of the GND pins on the same connector.

If using optos, then NPN wiring to parport GND pins will work.