Beware of this. The cap charges when the switch is open and then discharges a very high current pulse when the switch closes. This can damage the switch after even a small number of operations if the acp is too big. A lowish series resistance helps, by limiting the current - but needs to be chosen carefully or the effectiveness of the cap is lost. Or use a diode/resistor/capacitor combination ...... Not so much a problem with conductive rubber type switches but can be a real probem with small metallic types. Often it's just easier to handle in software. Richard P If its a switch that needs debouncing why not use a cap across the contacts. Art. ----- Original Message ----- From: "Mike Mansheim" To: Sent: Thursday, May 16, 2002 5:12 PM Subject: Re: [PIC]: S/W deboucing > > 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?) snip.... -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu