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max_gee
07-31-2002, 19:03
hi

Does any 1 know how to de-protect a 12c508??

Cheers

Max
gurmk
08-05-2002, 17:37
Have a look at the link below

http://www.cl.cam.ac.uk/~sps32/mcu_lock.html
Invisible
08-09-2002, 11:37
hi,

ok, I will give you practical trick for Flash mcu (not tested in cmos mcu like 12c508, 16c84, etc),
there are two ways of do it: power stress or power glitch,
in power stress you have to over-power the mcu (I donīt like it because mcu fries easily), in power glitch (what I use) you have to change vcc radomly, let see, for example, a pic 16f84, I use a piccard (satelite tv card) and put the mcu in the socket. Then with a regulated power supply I start to change vcc from 0 up to 5 volt radomly, then piccard is inserted in programer, I try to read, if fails I pull off the card and plug again. Note that power supply is all time changin radomly, this make the tick!, one of the time when you press read programer will start to read code ;)
Also note that this method could destroy ic, my success is about 2,5 ic to extract code. You will need some time to get it, (sometimes 5 minutes, sometimes several hours), but soon or later it will fail.

Hope this help you,
Invisible

PS: donīt mail me about circuit to change vcc radomly, I use my hand (at the end of the arm) to do it :D
max_gee
08-09-2002, 12:19
thanks for answer.

When i get some time i will design circuit to change voltage with frequency of change as well.

thanks again

Max
Invisible
08-09-2002, 12:25
hi,

thatīs will be fine, fried mcu are allways because of over-power,

best regards,
Invisible

PS: donīt tell anyone..:D :D :D :D :D :D
Sergey[Power User]
08-11-2002, 02:09
Hi!Hou're reading protected microcontrollers,right?
Let's ask,which microcontroller IC can be readed using this tricks and which can not?
Atmel ATMega?Texas Instruments MSP430F1xx family?Other than 16F84 members of PIC family??Something other??
Invisible
08-26-2002, 10:18
hi,

I donīt have list, I readed pics without problem but I think that some atmel could work too (not tested),

best regards,
Invisible
Sergey[Power User]
08-27-2002, 03:38
Okay,at least which PICs you can read??
All of them can be readed easily or not?
Invisible
08-27-2002, 10:09
hi,

I succeded to read: 12c50x, 16fxx,18f87x,

best regards,
Invsible
Sergey[Power User]
08-28-2002, 03:47
Sounds interesting;)Thanks for info.It is VERY interesting about protection properties of other controllers too...