Backdoor keys!!

[Franky_TJ_]

Hi, I;m trying to program the mc9s12xdp512. but when i do a Mass Erase the chip locks up. i need to know where to look for the backdoor keys.  These is the first place i started my serarch so  any will be apreciated thanks

[Franky_TJ_]

Hi! i finaly did it ...  turns out i was confusing the Security REGISTER with the Security BYTE... and also i wasent wating enough time for the MassErase to finish before  i executed the next command

[imajeff]

I haven't used S12X much, but I'm expecting it to be like the S12DP256:

As far as I know there should be no way to recover the backdoor key if you don't know what it is. That memory is not readable. Also if you knew the key but had not programmed any routine in the Flash that can enter it, or have not enabled backdoor access before securing it, then it should not be possible.

You should not need a backdoor key in order to unsecure the target. All you need is to completely erase Flash and EEPROM, and verify they are erased. Most often it is done using BDM (I use a D-Bug12 POD), and can also be done via external program (starting in expanded mode with external ROM).

None of this above will matter, however, if the problem is not that your target is secured. I don't call "locking up" a symptom of being secured, but it depends on what you are using to program it, and what does it do exactly? Do you have a BDM debugger?

[Franky_TJ_]

thanks for the replay...

and youre writght i didt need the back doorkeys.. It turns out that sense i'm using it in Special Single Chip Mode i dont need them.. there is another way to unlockit...

i'm using Code Warrior with HiWave. that has the unsecure comomand built in .. but i'm using a 9se64 to build a progrmmer. and the problem was that when a run a MASS ERASE the chip locks-up because the security byte is set 0xFF(secured mode) insted of 0xFE(unsecured).  Any way  i'm going to try the procedure that doesnt need backdoor keys, and see what happends.

in the Attach is simple bolck diagram.

Message Edited by Franky_TJ_ on 2006-10-1604:14 PM

Message Edited by Franky_TJ_ on 2006-10-1604:15 PM

[peg]

If this fails, try looking in pot plants near the door or on top of the architrave.

The keys are always there in the movies