Here's an article by Jack Ganssle exploring mechanical switches and contact bounce: http://www.embedded.com/showArticle.jhtml?articleID=18400810 The subject comes up often enough, especially with newbies that I thought it might be interesting to the list. Matt Pobursky Maximum Performance Systems -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu