Standard Parallel Port I/O

[Nyx]

I'm planning to use some USB/Parallel cables as a cheap way to get some digital inputs and outputs for my robot (at $5 each... how can I resist). I'm just wondering.... What is the limit to the number of parallel ports you can have on a PC (using linux)?

I would also like to know... How exactly do you go about writing a bit? Do you simply connect the input pin to a ground pin, say using a resistor? The SPP uses TTL logic, how is this usually done?

[Nyx]

Just to be more specific, I'd like to wire 5 push buttons into the status pins of a parallel port for inputs.

[alpha_geek]

I am using the parallel port under Linux too, try this link
http://tldp.org/HOWTO/IO-Port-Programming.html

[Nyx]

My question is about how you set a pin to high, from the hardware side...


But that page is interesting nevertheless.... The part about the joystick port and multivibrators sounds like joystick ports could be used for positional feedback. Do you think the same thing could be done over a parallel port?