How to excute the program in the secured S12X MCU?

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How to excute the program in the secured S12X MCU?

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a475334365
Contributor I

Hello,

      I'm using MC9S12XEQ512 MCU and CW IDE version 5.9.0. I get in trouble with a flash security problem.I've downloaded a program into the MCU by BDM and try to make it secured by setting flash security byte 0xBC at global address 0x7F_FF0F.It did work because the HI-WAVE interface didn't show any code there.After that,I want to unsecure it by meanings of backdoor key access,which has been included in the code.But it seems that the program doesn't run,because nothing was happened(I let the MCU send a CAN frame when it starts).So how could I excute the program?

Thanks. 

      

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lama
NXP TechSupport
NXP TechSupport

... and forgotten file...

L.

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528 Views
lama
NXP TechSupport
NXP TechSupport

Hi,

the debugger is not able (and not allowed) to communicate with secured MCU. The only what you can perform by debugger (via BDM) is the BDM command mass erase.
I hope you have read: S12(X) MCU Security 

Moreover, I can provide you test of security and backdoor key usage in very simplified code where it only unsecure the MCU which is programmed with given backdoor key AA AA AA AA AA AA AA AA.

When the code starts the MCU is secured and after execution of flash command:

 asm JSR Send_Command;
after previous setup the MCU is unsecured.

You can do any modification you want.

Do not forget to use FLASH NOUNSECURE command in your cmd file to be sure the MCU is secured after the code is loaded by BDM.

Best regards,

Ladislav

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