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TMS320F28384S: The usage of ePWM Action-Qualifier Submodule

Luke Chen
Expert 5090 points
Part Number: TMS320F28384S

Hi champs,

The AQ submodule can receive T1 and T2 events for PWM control, when TI event happens, the PWMA output can be changed according to the AQCTLA2 setting, with CMPA event comes later and then PWMA output will be changed according to AQCTLA register.

We can modify the CMPA content in ISR to avoid this situation. My question is that is there any better way to ignore CMPA event after receiving T1/T2 events within one PWM period.

Regards,

Luke

  • 0
    TI__Guru 52020 points

    Well if instead of using T1/T2, you use tripzone or digital compare, they always OVERRIDE the EPWM after action qualifier module which uses CMPA.

  • 0 in reply to Nima Eskandari
    TI__Expert 5090 points

    Nima,

    I understand TZ or DC submodule can do that, but with T1/T2 events in AQ submodule, we can control PWM output and don't need to take care of PWM dead band.

    So, do you mean in AQ submodule there have no other better way to ignore CMPA event after receiving T1/T2 events within one PWM period?

    Regards,

    Luke

  • +1 in reply to Luke Chen
    TI__Guru 52020 points

    Those are just events. They don't have any special ability to cause EPWM to ignore CMPA/CMPB. 

  • 0 in reply to Nima Eskandari
    TI__Expert 5090 points

    Nima,

    The events for AQ submodule are edge trigger, is this correct?

    If we connect SDFM CEVTOUT1 to ePWM X-BAR and then connect to DC submodule, generate DCAEVT1 as T1 event of AQ submodule. Because CEVTOUT1 if from comparator unit, it the SDCDATAx keep bigger than comparator threshold then the CEVTOUT1 will keep the output level all the time, is this correct?

    Is there any way to clear DCAEVT1 when TBCTR = Zero/PRD so that we can have edge to trigger TI event of AQ submodule in every ePWM cycle, like ePWM CBC function? I think modify DCTRIPSEL register in ISR should works, is there any hardware method to do this please?

    Regards,

    Luke 

  • 0 in reply to Luke Chen
    TI__Guru 52020 points

    Luke I think we had answered whether it is edge trigger or level triggered in another thread. I dont fully remember. Can you run a search real quick?

  • 0 in reply to Nima Eskandari
    TI__Guru 52020 points

    Luke did you check on this?