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C6472 - Disable Debug / Emulation

npb17
Expert 1615 points

Hi,

Is there a way to turn off debug support for the C6472 so attempts to connect an emulator will have no effect?  From the C6472 datasheet, the DBGM bit of the TSR register enbles/disables emulation.  Does it completely block JTAG debugging?  Or does it only prevent advanced emulation capabilities like trace?  Can this register be modified at run-time by a user application?

Thanks,

Nick

  • 0
    TI__Guru* 84110 points

    Nick,

    I do not believe there is a way to do what you describe. It is not entirely clear to me how the DBGM bit is implemented in the C64x+ (and later) cores.

    DBGM may be used for real-time mode emulation when interrupts can be allowed to continue running even while the emulator has halted the DSP.

    If the device does not implement Secure Mode, then you could not prevent a good hacker from getting emulation control of your device.

    But, try it. Set DBGM in your booted code and see if you can connect with the emulator and do any operations like Halt or view memory.

    Please let us know what you see when you try it.

    Regards,
    RandyP

  • 0 in reply to RandyP
    Expert 1615 points

    Writing '1' to the DBGM bit of TSR (to disable emulator capabilities according to the datasheet) has no effect on JTAG debugging from CCS.  As you mentioned, perhaps it must be for real-time mode only and disables only "advanced emulator features".  I was still able to pause, step, etc. after setting that bit.

    What is 'Secure Mode' that you mentioned?  How can I find out if that's implemented for the C6472?  I did not find anything in the datasheet in a quick search.

    I've also had difficulty finding details about lower level JTAG emulation (e.g. commands and what they do internal to the DSP).  Is that documentation something that must be purchased, for example in TI's EPK?

    Nick

  • 0 in reply to npb17
    TI__Guru* 84110 points

    Secure boot is a feature supported in some devices. If you search the datasheet for "secure" or "secure boot" and do not find anything, then it is not there. Take a look at the C6748 for an example of a DSP that does support Secure Boot.

    Yes, you would have to acquire the Emulation Porting Kit to get access to JTAG-level APIs.

    Even though you did not get the answer you wanted, please click Verify Answer on the post that most closely answered you so people will know which post to look at for the answer and so the support team will know you are done with this thread.

    Regards,
    RandyP

  • 0 in reply to RandyP
    Expert 1615 points

    Quick question about one other register:  What do the SEC_CTL bits do in the PRIVPERM register?  Does a permission value of b11 mean 'No Access is allowed' or 'All accesses are allowed' ?

     

    Nick

  • 0 in reply to npb17
    TI__Guru* 84110 points

    Nick,

    Please see the datasheet section 3.6.2 on page 76.

    Regards,
    RandyP

     

    If you need more help, please reply back. If this answers the question, please click  Verify Answer  , below.