>Date: Thu, 15 Feb 2001 14:34:28 +0200
>From: Jari-Pekka Heini <jari-pekka.heini@kolumbus.fi>
>
>I have attached a NES controller to my parallel port. Controller works
>fine except one thing: I can only press two (2) buttons at a time. If
>I press more than 2 buttons simultaneously, some of the buttons will go
>off. I've tested this joystick in my friend's computer and it works for
>him (he has the same build of the drivers and same kernel).
I think NES joysticks actually speak a serial protocol instead of
having discrete analog and digital inputs like PC joysticks. In
other words, there is a microcontroller in them that needs reliable
power to work right. Parallel ports don't have a "power" pin and
can't provide much power from the data lines - you might be having
trouble with the NES joystick drawing too much current from the
parallel port. The amount of power the parallel port can supply
varies with the port design, which could explain why it works on
your friend's computer but not on yours.
If this is the problem, you can probably verify it by connecting a
voltmeter across the joystick's power and ground pins and watching
it as you press various buttons. Or, try running the joystick's
power line to a source of +5v power (try the PC joystick port,
mouse port, keyboard port, or even a spare disk drive power connector)
and see what happens. If this is not practical, maybe you'll have
better luck with an add-in parallel port card or a different card
than the one you are using. If nothing else is practical, you might
try connecting a small electrolytic capacitor, say 10 to 47 uF or so,
across the NES joystick's power and ground pins. You'll still be
drawing a little too much current from the parallel port, but the
capacitor may help to smooth out the power glitches that may be
confusing your controller.
I hope this helps!
Matt Roberds
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This archive was generated by hypermail 2b29 : Thu Feb 15 2001 - 20:42:18 EST