How to from already burnt and recorded the chip well and read the procedure?

[Taiwan]

Hi~

Q : How to from already burnt and recorded the chip(MC9s12dg128b and MC9S08GB32) well and read the procedure or code? Thanks.

[Alban]

Hello,

A: For both MC9S12DG128B and MC9S08GB60 you need a BDM cable and you can dump the memory under CodeWarrior with the free version. You can only see the code if the devices are not secured.

If they are secured, the only solution is that the programmer enabled the backdoor key and you know how to start the mechanism. If you don't know there is NO SOLUTION.

Cheers,

Alban.

[imajeff]

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Alban wrote:
If they are secured, the only solution is that the programmer enabled the backdoor key and you know how to start the mechanism. If you don't know there is NO SOLUTION.

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In other words, the only way to unsecure the MCU (in order to read and burning new code) is to completely erase the program and data, then unsecure it. Unfortunately some old MCU maskset errata says there is no way to erase the memory without a backdoor already set up.

[Alban]

Hello,

The backdoor key allows a program to "un-secure" the MCU without mass-erase.

The routine must be executed in RAM and have access to FLASH (forcing the device to be in Single Chip Mode, NO BDM connection as it removes memory access when device is secured).

A typical way a software designer will trigger this routine could be through receiving a special SCI message which could even include the key itself.

Alban.