Post by thread:Desprotect PIC16C84

On Mon, 29 Sep 1997 14:10:12 -0700 WF AUTOMA=?iso-8859-1?Q?=C7=C3O ?= <spam_OUTwfTakeThisOuTAMBIENTE.COM.BR> 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.

WF AUTOMA‚ÌO wrote: > Steve Smith wrote: > > > > The EErom on an 84 is not protected only the code aera is protectable AFIK. > > > > Cheers Steve..... > > Sorry! I did reference for PROGRAM OF EEPROM if it's protected! I see in > somewhere that it's a > problem of 16C84! > > Miguel. Yip. Best solution is not to protect it ! Stupid solution, but apparently MChip advises one to only enable the CP flag the FINAL final program! Cheers! -- Eric van Es | Cape Town, South Africa .....vanesKILLspam@spam@ilink.nis.za | http://www.nis.za/~vanes LOOKING FOR TEMPORARY / HOLIDAY ACCOMODATION? http://www.nis.za/~vanes/accom.htm

> On Mon, 29 Sep 1997 14:10:12 -0700 WF AUTOMA=?iso-8859-1?Q?=C7=C3O ?= > <wfKILLspamAMBIENTE.COM.BR> 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 (my conjecture would be that the best goal would be to play VDD games to "trick" the part into thinking it's not code-protected, but that would require a lower VDD rather than a higher one). With the newer 'F84 parts, the old methods of cracking supposedly no longer work, but I have no idea whether new ones exist.

On Mon, 29 Sep 1997 16:46:21 -0500 John Payson <.....supercatKILLspam.....MCS.NET> writes: >> On Mon, 29 Sep 1997 14:10:12 -0700 WF AUTOMA=?iso-8859-1?Q?=C7=C3O >?= >> <EraseMEwfspam_OUTTakeThisOuTAMBIENTE.COM.BR> 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.

Steve Wrote: >The EErom on an 84 is not protected only the code aera is protectable AFIK. > >Cheers Steve..... I think you will find that the EEprom WILL be protected from reading with a prgrammer, but you still will be able to read and write to it from your code in your program. Regards, Brian.

<x-rich><bigger>---------- > From: WF AUTOMACAO <<<underline><color><param>0000,0000,ffff</param>wfspam_OUTAMBIENTE.COM.BR</color></und> erline>> > To: <underline><color><param>0000,0000,ffff</param>@spam@PICLISTKILLspamMITVMA.MIT.EDU </color></underline>> Subject: Desprotect PIC16C84 {Quote hidden}> Date: Saturday, June 13, 1998 12:37 AM > > Who was offering services for desprotect PIC16C84? Or have a > circuit to desprotect? > > MAW. </bigger> try this: DELLFERN, tel 0384 444570, fax:0384 444571 on their advertisement(ETI magazine february 1995, United Kingdom): we can copy any commercially available protected devices even if security fused or code locked. pal,gal,pic,mpu,etc goodluck http://www.poboxes.com/f f </x-rich>