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TMS320F28335: Trip-Zone Force Register (TZFRC) Operation makes EPWMs high

Dwijasish Das
Prodigy 40 points
Part Number: TMS320F28335

Hello,

I wanted to make EPWM1A, EPWM1B, EPWM2A and EPWM2B all low based on certain logic. I am using the Trip-Zone Force Register (TZFRC) for this. However, I see that when the forcing is done, all the EPWMs  become high. How can I make them low? I am using the following lines:

EPwm1Regs.TZCLR.bit.OST = 1;
EPwm2Regs.TZCLR.bit.OST = 1;

I have tried using the following code but it has no effect.  

EPwm1Regs.TZCTL.bit.TZA = TZ_FORCE_LO;
EPwm1Regs.TZCTL.bit.TZB = TZ_FORCE_LO;

EPwm2Regs.TZCTL.bit.TZA = TZ_FORCE_LO;
EPwm2Regs.TZCTL.bit.TZB = TZ_FORCE_LO;

Some help regarding this will be highly apprreciated.

  • 0
    TI__Guru* 80490 points

    Hi, due to inclement weather in our region, many of our subject matter experts are without power and unable to provide support at this time.  An expert will get back to you as soon as possible but it likely will not be until next week.

    Best,

    Matthew

  • 0
    TI__Mastermind 42195 points

    Dwijasish,

    the TZ is simply forcing the PWM low, it has no other effect on the PWM generation. When you remove a TZ force condition the PWM will attempt to output whatever you have told it to do. If you left your counters running and the action qualifier or Dead band submodules are setting the PWM's output high then the PWMs output will be high once the Trip zone forcing condition is removed. You can change these inputs before removing the TZ forcing condition and it will allow the device to output whatever you set it to.

    Regards,
    Cody 

  • 0 in reply to Cody Watkins
    Prodigy 40 points

    Cody,

    Thanks for your response. I investigated a bit and I found that I had written the TZ_FORCE_LO for the TZCTL in the EPWM initialization function. When I brought it to the main code after TZFRC. The issue was resolved.

    Regards, 

    Dwijasish