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Original question:

CCS/F28M36P63C2: EPWM outputs issue

CCS/F28M36P63C2: EPWM outputs issue

Srinivasan Venkatasubramani
Expert 1455 points

Part Number: F28M36P63C2

Tool/software: Code Composer Studio

Hello,

How do i make EPWM 1A and EPWM 2B look identical and disable EPWM 1B and EPWM 2A at the same time?

I tried it this way

// Action Qualifier SubModule Registers
    EPwm1Regs.AQCTLA.bit.CAD = AQ_SET;
    EPwm1Regs.AQCTLA.bit.ZRO = AQ_NO_ACTION;
    EPwm1Regs.AQCTLA.bit.CAU = AQ_CLEAR;

    EPwm1Regs.AQCTLB.bit.CAD = AQ_NO_ACTION;
    EPwm1Regs.AQCTLB.bit.ZRO = AQ_NO_ACTION;
    EPwm1Regs.AQCTLB.bit.CAU = AQ_NO_ACTION;


        EPwm2Regs.AQCTLA.bit.CAD = AQ_NO_ACTION;
        EPwm2Regs.AQCTLA.bit.ZRO = AQ_NO_ACTION;
        EPwm2Regs.AQCTLA.bit.CAU = AQ_NO_ACTION;

        EPwm2Regs.AQCTLB.bit.CAD = AQ_SET;
        EPwm2Regs.AQCTLB.bit.ZRO = AQ_NO_ACTION;
        EPwm2Regs.AQCTLB.bit.CAU = AQ_CLEAR;

Ironically i am getting identical outputs on EPWM 1A and EPWM 1B.

No outputs in EPWM 2A and EPWM 2B??

Any insight is appreciated,

Thank you,

Srini

  • 0
    TI__Genius 10820 points
    Hi Srini,

    Have you configured the two PWMs identically (time base counter, TBPRD, CMPA, counter modes, clock enables)? Make sure you write the same value to PWM1 and PWM2 CMPA registers.

    Hrishi
  • 0 in reply to Hrishi Nene
    Expert 1455 points
    Hey hrishi,

    Thanks for your time and assistance. I double checked all those values, they are identically configured. i set identical values to the two CMPA registers as well.

    Srini
  • 0 in reply to Srinivasan Venkatasubramani
    TI__Genius 10820 points

    Hi Srini,

    In that case this is strange behavior. As you rightly said, PWM1B is not expected to be identical to PWM1A based on your configuration. Is it possible that you are looking at the wrong output pins? I know this device is pretty big and it is easy to probe the wrong pins. Please make sure that all muxes are correctly selected to bring out PWM1A and PWM2B to the pins you are probing. Are you using one of the example projects? If yes, which one? Are you using your own control board?

    Thanks.

    Hrishi

  • 0 in reply to Hrishi Nene
    Expert 1455 points
    Hey hrishi,

    I verified that i am using the correct pins by running a TI example on my hardware and it runs as expected. This is definitely a software issue. I am using the Control card provided by TI , But the docking station is not the one provided by TI. That is my own hardware design. And i double checked my hardware by running TI Examples and my previous projects and it checks out just fine. The issue is with my firmware. I double checked the Pwm mux configurations and the probe pins. They are fine. I am not working on any example. This is a personal project to design a Battery charger based on switch mode power supply. I shared my code in a question relevant with this thread. I detail everything there on how i constructed my design there. And i would love your take on it and any advice you have to offer. Thanks a lot.

    Srini