MC68HC908 micro-controller

Discussion in 'Embedded Systems and Microcontrollers' started by sesenergy, Oct 9, 2012.

  1. sesenergy

    Thread Starter New Member

    Oct 9, 2012
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    Hi everyone. I am looking to access and program a micro-controller MC68HC908. I have purchased a P&E multi-link interface and software to facilitate this. However, I believe the micro-controller is protected and therefore I cannot gain access to the data. Does anyone know if it is possible to get access to the data, change it or re-write?

    Thank s for looking at my post and I look forward to some replies :)
     
  2. MrChips

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    Oct 2, 2009
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    Why do you believe that the mcu is protected?
    What is the full part number of the mcu?
     
  3. Papabravo

    Expert

    Feb 24, 2006
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    If you can get the chip out of its package and can examine it with a powerful microscope you can eventually extract the binary values of the instructions. Best would be a ceramic package with a quartz window; worst would be a plastic package. The problem is removing the plastic from the chip without damaging it. You need a powerful economic reason to do this as it is very expensive and time consuming.
     
  4. MrChips

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    You must be pulling my leg. How do you detect the binary status of a memory cell under a microscope?
     
  5. Papabravo

    Expert

    Feb 24, 2006
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    Well I've never done this myself, but I have heard of it being done. It might not be an optical microscope, but maybe an electron microscope. Due to the obvious impediments it is beyond the capabilities of most hobbyists.

    For example check out the following:
    http://www.cl.cam.ac.uk/~sps32/mcu_lock.html
     
  6. MrChips

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    I would think that an electron microscope would wipe out the charge in a flash memory cell.
     
  7. sesenergy

    Thread Starter New Member

    Oct 9, 2012
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    Thanks Mr Chips and Papabravo for looking at my post.
    The data is protected due to the inherent design of the microcontroller - to stop it being altered, copied or viewed. The MC68HC908 is the generic family name which come in a variety of packages. During production the flash memory is accessed and the information is written to the chip. This is done on mass with many thousands of devices being programmed in a production run. This particular chip was designed by Motorola which is now Freescale but as expected the information to access a given program is not freely available. It is also a legacy product which I had hoped would mean easier access to the information required but this is not the case. I assume Freescale would not have access to their customers information anyway.

    Thank for looking again and if I find a way I will post on the forum.
     
  8. MrChips

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    Almost all MCU chips have a ROM protect bit to prevent IP theft. If the protect bit has been activated you are locked out and out of luck.
     
  9. Papabravo

    Expert

    Feb 24, 2006
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    I disagree. As the article I referenced clearly spells out, it is only a matter of time and money.
    It turns out that it is an optical microscope that can detect the presence or absence of a transistor in some ROM technologies which determines whether a bit is a 1 or a 0.
    @sesenergy -- I am very familiar with the Freescale(formerly Motorola) processor that you mentioned having work with it for a number of years.
     
  10. MrChips

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    Fine. Come back to me when you have successfully read a locked ROM in an MCU.
     
  11. Papabravo

    Expert

    Feb 24, 2006
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    I have no interest in actually doing so. That being the case you may be waiting a long time for me to get back to you on this one. I'm just pointing out that a sufficiently motivated pirate can break the MCU security with enough time and resources. You are correct in stating that the casual hobbyist or worker bee in a typical corporation has no chance of doing this in reasonable time with a small budget.
     
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