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TMS320F280049C ADC issue

keysfine
Prodigy 80 points

Hello all:

I am using DSP-TMS320F280049C for software development. When Debugging ADC module, I encountered a problem:

  • The 10th  pin of the DSP chip ( the function is ADC-A3), when no signal input, a 3.62V level is detected above the pin.

    • This level still exists after I try to erase the flash program. And I still measured a 3.62V voltage signal on the pin after I dropped it.

Is there any other function of this pin or is the level of this pin related to the chip peripheral configuration circuit?

Thank you!

Due.Yuan

  • 0
    TI__Mastermind 34655 points

    Hi Due,

    Can you let me know what board you are using and on how many units you have observed this to be happening?  A3 is mux'd with inputs 0/3 of internal comparator subsystem CMPSS1.  You should not see any voltage on this pin at power up.  Try checking on other units/boards first to see if what you are observing is a only true for a particular board or unit.

    Regards,

    Joseph

  • 0 in reply to Joseph Casuga
    Prodigy 80 points

    Hi Joseph,

    The chip has been used on the prototype circuit board developed by ourselves, and this phenomenon can be observed on all the unit boards.

    Regards,

    Due.Yuan

  • 0 in reply to keysfine
    Prodigy 80 points

    Hi Joseph,

    Thanks for your feedback. I also want to know:

    1. Is the current phenomenon a risk to the use of chips?

    2. Is there a way to avoid the current problem?

    3. Can you provide the internal circuit structure of the pin?

    Regards,

    Due.Yuan

  • 0 in reply to keysfine
    TI__Mastermind 34655 points

    Hi Due,

    Something does not seem right with the setup.  You should not be seeing a 3.62V level on A3 upon device power up.  Can you share your circuit schematic if possible and we will try to see what might be causing this issue?

    Thanks,

    Joseph

  • 0 in reply to Joseph Casuga
    TI__Mastermind 34655 points

    Hi Due,

    Had not heard back from you on this issue so I am assuming that you haved resolved it, hence marking this post closed.  If you still have issues with this topic, please post it in the forum and we will look into it further.

    Regards,

    Joseph