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MSP430FR5972: How could I protect (via SW) FRAM against EM disturbances?

Part Number: MSP430FR5972

Good morning everybody, 

I'm writing this post because I need your help so that I can (I hope) fix this annoying issue I'm facing.

I have some problems with MSP430FR5972 FRAM: there are some boards (on which there is MSP430FR5972 uP) which, in a random unpredictable way, don't work properly because the processor's FRAM is erased form EM disturbances in any form.

In this scenario, is there the possibility to protect FRAM against such disturbances via software?

All I want to do is to protect the lower 32KB code memory. Are there any example which I can refer to?

Any help and advice would be really appreciated!

Best Regards, 

Maria Angela

  • Hello Maria,
    usually the portion you can do on the SW side is significantly less than what can be done in HW. This is related to the point, that the origin of the problem is not the SW but the disturbances and the immunity of the designed HW versus these disturbances. Thus it is hard to reduce the impact by SW. Still there might be some options to do, but for this it is essential to understand the failure mechanisms and the details of the HW design. One possible source of poor immunity would be overclocking the CPU, resulting from disturbance. This mainly can happen, if external clock sources are being used, e.g. crystals or ceramic resonators, and the digital clock is being used without a pre-divider for the CPU. This can result in duty cycle shifts or even glitches on the clock, which overclock the CPU.
    But as stated, there are tons of other possible root causes, thus if you want to go into further details, I need to understand the details of your application perfectly. You can share sensitive material through the E2E system, by requesting a friendship with me. After my acceptance, you can post me privately any information, without disclosing it to the E2E community.
    In terms of documentation/application reports, we have only some reports on the HW related aspects of EMI robustness as this is the main aspect, when it comes to immunity. Everything else is trying to cure mistakes, which happened somewhere else. I know, this is commonly a pain, as HW changes are not easy and time consuming.

    Best regards
    Peter
  • Hello Maria,
    please let us know whether you need further support on this problem. If not please close the thread. Many thanks in advance.

    Best regards
    Peter
  • Good Morning Peter,

    thank you very much for your detailed and clear answer.

    I perfectly understand what you wrote about HW design aspects but maybe I'm not being clear in my previous post. I'm not worried about HW design at all because it is used in many other application and anything works well.

    What I want to understand better is how I can protect my FRAM using the memory protection unit and if it is possible to protect only a FRAM area so that I can ensure a much more robust application to my clients.

    My starting point is SLAU367G  (the programming guide of MSP430FR58/59/68/69XX FAMILY), in particular Chapter 7: Memory Protection Unit.


    As said before, any comments, help and advice would be really appreciated!

    Best Regards,

    Maria Angela 

  • Hello Maria,
    sorry for having misunderstood your question. Well the memory protection feature can enhance the protection of your FRAM based device and application in the sense of protecting the code execution and constant area against unintended write accesses, which could result from high disturbance levels, either corrupting the used crystal or resonator clock source or of course at very high disturbance levels corrupting signals on chip "directly".
    The description of all the details would lead too far, if trying to rephrase all the details here. Please see for further details the www.ti.com/.../slaa628.pdf which contains a complete chapter related to these topics, on one hand explaining the features and how they should be used, and showing the necessary steps and configurations in IAR and CCS.

    Using the MPU for these purposes is definitely recommended (please see also our documentation).

    Of course the device related features are described in the chapter of the User's Guide SLAU367G you mentioned.
    Please read both documents. If further questions should come up, of course you can come back to us on those.

    Best regards
    Peter
  • Hello Maria,
    are there any further questions on this from your side?

    Best regards
    Peter
  • Good morning Peter,
    Not at the moment!
    If I need any further help I would re-open this thread, ok?

    Thank you for your clear answer.
    Best Regards,
    Maria Angela