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CCS/AM3352: Periodic RAM check for SIL2 certification

user5655976
Prodigy 190 points

Part Number: AM3352

Tool/software: Code Composer Studio

Hello, guys

I am a software engineer working on a project need certification SIL2. The asseor requires us to implement a perodic check on ram to ensure no ram access failure. In our option, this should be done by a solution combination software and hardware. So we need some advices about this solution to check ram perodically.

  • 0
    TI__Guru**** 393215 points
    Hi,

    What software are you using? What solution do you have in mind?
  • 0 in reply to Biser Gatchev-XID
    Prodigy 190 points

    1 We design and implement application running on RTOS. As we know, there is no such ram check function in RTOS. So we have to add this in our application.

    2 According to the Standard, this function writes given data to one memory cell, then read back all data from other cells, and then check those data. Those three steps are repeated until all memory cell written and checked.We think it can not be done by only software. Then we wonder if it could be done with ECC support. 

    Since we have no experience, we are just design this by imagination. So we need some advice. Or if it is possible, a method.

        

  • 0 in reply to user5655976
    TI__Guru* 95265 points
    Hi,

    If you have a test application running and want to periodically check the integrity of RAM, you may need to move your program and data to a different location other than the area being tested. Then you can use a periodic timer ISR to do the memory fill-in and readback test.

    Regards, Eric
  • 0
    TI__Guru** 116980 points
    Since this question relates to functional safety, your understanding is correct that the implementation needs to have a solution that is a combination of software and hardware. Implementing a walking bit DDR memtest will address the issue from a software perspective but AM335x doesn`t provide DDR ECC support and we would need to check with design to provide any guidance from HW perspective.

    Let me point you to some recent discussions and see if some of the responses here help with your understanding:
    e2e.ti.com/.../2578485

    TI Hercules family of devices have such functionalities as they are designed to be safety certifiable but we may need to look at AM335x design to check on how the HW requirement of safety can be addressed
    e2e.ti.com/.../1386719

    Hercules safety manual/Diagnostics:
    www.ti.com/.../spnu511d.pdf

    The request for supporting effort for functional safety certification can`t be supported on the E2E forums for this device as I indicated on the other E2E thread. If this is a critical product requirement then I would recommend that you get in touch with your local TI representative and provide details on your usecase so the request can be routed to the BU/design folks for evaluation.

    Regards,
    Rahul