Re: "att caudlet" Limit switch problems

Okay, I studied this drawing again and realize that you have a 10K
tied to +5 on one end and the other is tied to one of the contacts on
the switch and that contact is in turn tied to a parallel port pin.
In essence you have an external 10K pull-up. Activation of the
switch pulls the pin low. By wiring the switches in parallel you
have created a logic "NOR" gate so that if any switch is activated
then then pin should go low. By tying the Home pin to the Limit pin
you are connecting these port pins together. Assuming they each have
internal pullups that could cause problems/interactions on the pins.

If you want to continue to use this setup put small diodes in
series with each switch so that the cathode is connected to the
junction of the pull-up and the pin and the anode goes to the correct
parallel port pin. There should be a separate diode for each switch.
It's okay to tie two or three of the anodes together at a single port
pin. This will isolate each switch so that the condition of the
other switch or the state of a given parallel port pin will not
effect another.

Drop me a line if it doesn't make sense and I will draw a schematic
(I am no good with ASCII drawing :=o)