>Consider what happens when you have a large capacitor (say 10uF for >arguments sake) and you turn off the power to the PIC system. What is the >lowest resistance for the capacitor to discharge through? The ESD protection Whoops foot in mouth time - of course there is no ESD diode to Vcc, because the programming voltage goes in here (RED) :) (/RED) -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads