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TMS320F280049C: XDS110 disconnects due to switching noise

Peter Kozlowski1
Prodigy 190 points
Part Number: TMS320F280049C

I am using a XDS110 debug probe to connect to a 280049C on a power board. I have disconnects when I go to higher voltages and currents which suggests noise issues.

Is there a setting on the debugger that is known to be more reliable in high noise environments? JTAG, SWD Mode, cTag? Or can I change any other settings to increase noise immunity?

Thanks

  • 0
    TI__Mastermind 28275 points

    Hi Peter,

    Is there isolation between the debugger and your power board?

  • 0 in reply to Frank Ankapong
    Prodigy 190 points

    The powerstage is galvanically isolated from the controller and we are additionally using a USB isolator in line with the debugger. Pretty much everything is isolated from everything else at this point.

  • 0 in reply to Peter Kozlowski1
    TI__Mastermind 28275 points

    This might actually be due to the device being disturbed rather than the JTAG connection. Can you monitor the XRSn pin of the device when you go into the "high voltage and currents" state? Monitor it on a scope to see if XRSn ever goes low.

  • 0 in reply to Frank Ankapong
    Prodigy 190 points

    I can and will on the next chance I get (winter holidays are coming up and the labs are currently used for other things). However, I don't think there is a device reset issue. I have a CAN communication running and the controller stays operational and maintains the same state when the debugger disconnects. On controller reset the state machine would start in an "off" state but I know from the CAN communication that the system maintains "operate" state. There's also no unexpected switching behavior and the controller even maintains last commanded dutycycle values.

    Or did you mean that the debugger could disconnect when there is a disturbance on the XRSn even if it's not large enough to reset the controller?

  • 0 in reply to Peter Kozlowski1
    TI__Mastermind 28275 points

    Hi Peter,

    If the CAN communication maintained the same state, then most likely the device didn't reset but we will still need to confirm it. Please also scope the 3.3v supply along with XRSn.

    Is the JTAG 3.3v supply and device 3.3v supply the same?

  • 0 in reply to Frank Ankapong
    Prodigy 190 points

    Hi,

    sorry for the long delay in my reply.

    We have resolved the issue but have not as such found a single source for the problem. The source seems to have been noise from the power stage causing the debugger to disconnect. We applied filtering measures on all pins, reduced the TCK frequency and switch from JTAG to 2-Wire cJTAG. Each of those measures seems to have incrementally increased the noise immunity until we stopped having problems at all.

    Thank you for your support.

    Peter

  • 0 in reply to Peter Kozlowski1
    TI__Mastermind 28275 points

    Hi Peter,

    That's great to hear! Let us know if you ran into anymore issues.