expanding lpt port

[scott m]

Is it possible to expand the parallel port on old hp computer so that there are more pins available to do stuff with? I am just starting to mess around with this stuff and have blown out 2 pins on the port (no real worry, only $30.00 computer) so I would like to add something. I think I read somewhere about adding a whole port/output but am unsure. Any help appreciated. Scott. I already posted this before it occured to me it may be the wrong forum. I am running steppers with it though . New to cnczone.

[ViperTX]

You should be able to add an ISA card with 2 additional parallel ports...check that they are bidirectional...some code that I've seen uses this feature.

[scott m]

Well thanks for the pointer in the right direction. I'd have replied sooner but I had to track down my own post, it seems to have happy feet . I am using C++ and I suppose I could access this address with it. Is that the limit on how many ports I could use?

[ViperTX]

The port limitation is more a Microsoft limitation then anything else. You could write a separate port driver routine to use additional ports.

[Al_The_Man]

Here is a PDF on programming the parallel port in C and covers details.
Al

[scott m]

Well thanks for helping me with this problem. It is fixed. Al, how on earth did you get all that into a 76kb pdf? I have never downloaded something so fast on my junk dial-up. IF I made a pdf with that many pages it would be about 4 mb . Some nice info in there too. I am relatively new to electronics so I imagine I will be posting a bunch of dumb questions from time to time. Scott.