QBASIC, Parallel Ports, and Windows XP

[Venkatesh]

For a little piece of technology I am building, I am having a computer control a motor assembly. The computer, running Windows XP, is using the parallel port and QBASIC to control a buffer (7407), which is controlling a transistor. Under Windows XP, the parallel port takes several seconds to change the status of the parallel port, if it even successfully changes it at all. Many attempts fail with no reason given, and those which do succeed take up to 20 seconds to change the parallel port's output.

Does anybody know why this is happening and how I might be able to overcome this problem? Allocating an IRQ to the parallel port has not fixed anything.

As a side note, the parallel port on my machine outputs 3.2 Volts when it is high, and roughly a .5 volts when low. I have checked other computers, many of which output roughly 5 volts on high and ~0.1 volts at low. I would try another machine, but this one is a laptop.

[kid robusto]

i would try to use win98 or even win95. You could use a disk partition tool and free up like 500 meg of your hard drive, and multiboot to 95/98. Also it sounds like your laptop may be giving low voltages when your on battery packs, did you try when your plugged into the wall?

if all else fails find an old p1 box( many can be found on sides of roads) and use that to test your stuff.

Do you have any schematicsand/or code you could post? I have wanted to interface my PC and servo/motors but i dont know how to use qbasic to well.