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TMS320F28388D: Does HWBIST include the Missing Clock Detect (MCD) Logic unit self test

Nai Wen Li
Prodigy 90 points
Part Number: TMS320F28388D
Other Parts Discussed in Thread: C2000WARE

Tool/software:

Hi I want to check if the Missing Clock Detect (MCD) Logic unit test is included in the HWBIST?
If not, how do I make sure whether the MCD is failure?

Best Regards,
Norman

  • 0
    TI__Guru* 81850 points

    Norman,

    HWBIST does not have coverage on the MCD logic on this device.  

    If you wanted to test the XTAL input, you could turn off the XTAL circuit using OSCOFF bit in XTALCR register and then you should see MCD activate.

    Have you considered using the DCC(Digital Clock Compare) module?  It is more flexible than the MCD, can take many other sources, and not only detect missing clock but also out of spec clock.

    Best,
    Matthew

  • 0 in reply to MatthewPate
    Prodigy 90 points

    Hi Matthew,

    Thanks a lot for your clarification. I agree with you that the DCC (Digital Clock Compare) module is indeed more flexible compared to MCD and easy to use, especially since it can monitor multiple clock sources and detect not only missing clock but also out-of-spec conditions.

    I would consider to integrate DCC into my diagnostic flow. However, I would like to ask about how to properly perform a self-test on the DCC itself.Is the recommended practice to inject an artificial error (e.g. configuring mismatched compare values or intentionally disabling one clock source) and then verify whether the error handling mechanism is triggered? Or is there a more formal/self-contained method supported on this device for validating DCC functionality?

    Best regards,
    Norman

  • +1 in reply to Nai Wen Li
    TI__Guru* 81850 points

    Norman,

    I'll refer to the safety manual for both modules. https://www.ti.com/lit/fs/sffs022/sffs022.pdf 

    There is a self test code for MCD in our SDL folder

    C:\ti\c2000\C2000Ware_6_00_00_00\libraries\diagnostic\f2838x\examples\sdl_ex_mcd_test

    Here is what the SM mentions on DCC 

    6.2.4 Software Test of DCC Functionality Including Error Tests

    A basic test of DCC functionality (including error generation) is possible via software by programming a sequence of good and bad expected clock ratios and executing DCC operations with software confirming expected results.

    So to your point I believe both of these self test mechanisms follow your first conclusion, i.e. injecting artificial error.  

    Best,
    Matthew

  • 0 in reply to MatthewPate
    Prodigy 90 points

    Hi Matthew,
    I think I have get all the information that I want, thanks for the fast  and precise reply !!!

    Best Regards,
    Norman