> I am trying to use a push button to trigger the
> external interrupt of RB0. However I need to implement
> a s/w deboucing in my code to prevent multiple
> triggering of the interrupt.
> How do I go about writing the code for the s/w
> deboucing? (using delays?)

If you truly want to prevent "multiple triggering of the interrupt",
then you need to debounce in hardware.
Do you need the button on the interrupt?  I guess I wouldn't use the
interrupt feature of portb.0 with a bouncy push button.  If you are
just looking for button presses, I would establish a periodic interrupt
like Olin mentioned, and poll the input with a software debounce.  I
don't like using delays for this type of debounce - there's usually
other stuff that needs to get done.
Here's some pseudo code (is there an official way to write pseudo code??)
that hopefully illustrates one way to get a 50 ms debounce:

  - happens every 1 ms via a timer based interrupt (but I don't like
    stuff like this in the actual isr)
  - variables:  BUTTON_STATE, DEBOUNCE_COUNTER
  - use BUTTON_STATE, not PORTB.0 for any button based decisions in
    the rest of your code

if (PORTB.0 not equal to BUTTON_STATE): increment DEBOUNCE_COUNTER
else:                                   DEBOUNCE_COUNTER = 0

if (DEBOUNCE_COUNTER equal 50): toggle BUTTON_STATE
                                DEBOUNCE_COUNTER = 0

Sometimes processing is required at the transition (for example, save
data when the button is released).  When BUTTON_STATE is toggled,
either flag that a transition occurred, or do whatever processing is
required.

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