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TMS320F28379D: ePWM interrupts on TBCTR = CMPA and also on TBCTR = CMPB

gustavo zarba
Expert 1110 points
Part Number: TMS320F28379D

Hi der people,

by my application I need to generate two interrupts per ePWM-Period. The one on TBCTR = CMPA, the other on TBCTR = CMPB.

Now, if I understood correctly, when I set

EPwm2Regs.ETSEL.bit.INTSELCMP = 0;    //  Enable event time-base counter equal to CMPA  or to CMPB when the timer is incrementing to INTSEL selection mux.

EPwm1Regs.ETSEL.bit.INTSEL = 100;       //  100: Enable event time-base counter equal to CMPA or CMPC when the timer is incrementing

I would get an interrupt on CMPA

This means, if I also want an interrupt on CMPB I need to change the register inside the interrupt routine to this :

EPwm1Regs.ETSEL.bit.INTSEL = 110;     //  110: Enable event: time-base counter equal to CMPB or CMPD when the timer is incrementing

And set it back by the next inerrupt to

EPwm1Regs.ETSEL.bit.INTSEL = 100; 

Is there another way I am overlooking?

Thanks and best regards!

Gustavo

  • 0
    Expert 1110 points
    Sorry, there is an error there:
    "EPwm2Regs.ETSEL.bit.INTSELCMP " should be "EPwm1Regs..."
  • 0 in reply to gustavo zarba
    TI__Guru 52010 points

    Unfortunately, the feature you are looking for doesn't exist. There is no register you can set to get both CMPA and CMPB to cause an interrupt. The first solution for this, you have already implemented, which is switching the interrupt source in the ISR, knowing whether CMPA happens first or CMPB.

    There is another option, you can sync an unused EPWM, lets say EPWMy to operate exactly as EPWMx (your original EPWM) and have interrupts for it occur at CMPB. This way you have both interrupts.

    Nima Eskandari

  • 0 in reply to Nima Eskandari
    Expert 1110 points
    Thanks Nima,
    this is a good idea!
    I will experiment with this.
    Best regards,
    Gustavo