On Mon, 29 Sep 1997 16:46:21 -0500 John Payson writes: >> On Mon, 29 Sep 1997 14:10:12 -0700 WF AUTOMA=?iso-8859-1?Q?=C7=C3O >?= >> writes: >> >Does someone know how to desprotect a EEPROM of PIC16C84? >> >> The method reported a couple of years ago was to raise Vdd to about >12V, >> go into programming mode and write 1 to the CP bit several times. >Upon >> lowering Vdd to normal range, the chip could be read unprotected, >both >> the program and data EEPROM. I never tried it though. > >I've also read that that 'exact' method is a trap (something to try to >entice people to blow up chips, maybe?) but that at least for the >older >parts there were related methods that did work I'm not presenting this as an exact method, or recommending anyone try it, since I don't remember what the exact method was. There were reports that simply raising Vdd and letting fly was likely to damage the PIC, so enhancements such as letting the chip "cool down" for a few minutes at various stages in the process, etc. were presented. I didn't attempt any of this, my interest was just that a method did exist using readily available hacker technology, thus I couldn't consider the code and data in a C84 to be secure.