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TMS320F28388D: PWM output high while connect emulator

Terry Deng
Intellectual 2535 points
Part Number: TMS320F28388D
Other Parts Discussed in Thread: C2000WARE, TMDSCNCD28388D

Dear,

Customer report F28388 PWM pin will keep high level output for several ms while connect emulator, it will damage their power circuit.  Do you have suggestion that PWM could trun off to Low level output immediate while connect emulator?

I validate it on TI EVM TMDSCNCD28388D + DockingStation_ HSEC_120or180pin, and run TI example code "epwm_ex4_deadband.c" from C2000Ware_3_03_00_00\driverlib\f2838x\examples\c28x\epwm

As below picture, we monitor the GPIO04 pin running for PWM3A function, then it will keep continue high output ~100ms while connect emulator in CCS.

  • 0
    TI__Intellectual 2535 points

    More information, customer hardware board already has pull low resistor in the PWM pins, however it still will keep high level output for long time while connecting emulator.

  • 0 in reply to Terry Deng
    TI__Guru 52020 points

    What is their setting for: 

    TBCTL.FREE_SOFT 

    In their EPWM registers?

    Nima

  • 0 in reply to Nima Eskandari
    TI__Intellectual 2535 points

    Hi Nima

    I confirm the TBCTL.FREE_SOFT is 00 as below, however it still will happen the issue what I mentioned.

  • 0 in reply to Terry Deng
    TI__Guru 52020 points

    Does the time at which the debugger gets connected affect your EPWM output? If the output is high, does it stay high, and if the output was low would it stay low?

    ALSO,

    If you set FREE_SOFT to 0x11, would it continue to operate as expected? Since in this current mode (0x00 mode) the EPWM would get stuck at the same TBCTR value and halt the signals in their current state.

  • 0 in reply to Nima Eskandari
    TI__Intellectual 2535 points

    You are correct, the time at which the debugger gets connected affect the EPWM output. It means that PWM will stay high if the output was high, and stay low if the output was low.

    And when set FREE_SOFT to 0x11, the PWM will continue output until they all turn off to low.

    However the question is why F28388 behavior is different with others C2000 device when FREE_SOFT as 0x00 status. I have test F28377 and F280049, both they will turn PWM to low when connected debugger under FREE_SOFT as 0x00 condition. Only F28388 have issue that PWM will stay high when connected debugger.  

  • 0 in reply to Terry Deng
    TI__Guru 52020 points

    Terry,

    Glad switching to 0x11 helped.

    As far as the difference between the devices, are they running identical configuration?

    Also could it be the way the debugger is connecting is different? One is connecting without halting the CPU while F2838x does?

    Nima

  • 0 in reply to Nima Eskandari
    TI__Intellectual 2535 points

    Hi Nima

    We validate the PWM behavior in difference device by both using TI example code, and both using same debugger XDS100v2.

    Could you try investigate below example code in your EVM and check if recur my report issue?  If you can recur it, I will suggest we find the root cause and possible workaround, because it should be a serious issue which will damage customer power circuit. 

    "epwm_ex4_deadband.c" from C2000Ware_3_03_00_00\driverlib\f2838x\examples\c28x\epwm

    "epwm_ex2_updown_aq.c" from C2000Ware_3_03_00_00\driverlib\f28004x\examples\epwm

  • 0 in reply to Terry Deng
    TI__Guru 52020 points

    I will report this to the CCS team and the SW team to see if there is a debugger setting specific to F2838x or anything in the initializing GELs that causes this.

    Thank you for finding this.

    Nima

  • 0 in reply to Nima Eskandari
    TI__Intellectual 2535 points

    Nima

    When you contact with CCS or SW team relation colleagues, may I be loop into the mail? Because I would like to continue understand and discuss the detail. thank you.  

  • 0 in reply to Terry Deng
    TI__Guru 52020 points

    I looped you in.