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CCS/TMS320F28035: identify the reset reason

user5019379
Intellectual 370 points
Part Number: TMS320F28035


Tool/software: Code Composer Studio

hello sir/madam,

i have a project on 3.3KW on board charger that using 2 tms320f28035 for PFC and LLC regulation respectively.
the MCU for PFC reset at times, i want to identify the root cause of it.

now, in the code,

1,watchdog is disabled.

2. internal RC oscillator 10M is used and PLL　60M.

i have already check the 3.3v power supply when reset, it seems ok.

please help to give me some advice or direction on how to get the reset reason on TMS320F28035. thank you very much.

  • 0
    TI__Guru* 95315 points

    If the WD is disabled and INTOSC is used, then reset source is unlikely to be the WD or the NMIWD. It is likely some external noise is triggering the reset. Do you have a lot heavy switching going on? Are your boards inside shielded enclosures? Have you measured the noise riding on your power bus?

  • 0 in reply to Hareesh Janakiraman
    Intellectual 370 points

    yes, it reset when it run with a heavy load.

    i have already catch the noise on power bus, through there are some noise, maybe coupled by the probe, the signal seems ok.

    and before the 28035 reset, the pfc input current is fly-up to a big value.

    i don't know the reset cause the current fly-up or vice-versa.

    do you have any advice?

  • 0 in reply to user5019379
    TI__Guru* 95315 points

    It does appear the reset is noise-induced. It could be quite a challenge to isolate the source of the reset. If the reset is reproducible "at-will", it makes the debug a bit easier. You first need to determine if the noise is conductively coupled or radiatively coupled. It is hard to debug these issues without access to schematics/layout and the actual hardware. One can only come up with some general tips/suggestions.

     

    Please scope the VDD, VDDIO and -XRS pins to look for significant excursions when the reset happens. Significant rail excursions may indicate inadequate power-supply decoupling. Also consider stiffening the PU resistor and PD resistor on -TRST pins.

     

    Please do search the forum for some tips. This issue has been discussed quite a few times. An example is at:

    https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/377006?tisearch=e2e-quicksearch&keymatch=reset

  • 0 in reply to Hareesh Janakiraman
    Intellectual 370 points
    hello sir,

    thank you for you patiently explanation for this.
    at the end, we found that in some condition, the close loop is not stable and cause a big current inrush, and it is lucky that it just cause the MCU rest.