TMS320F28027: TMS320F28027

Hi;
For the same problem;
When I am using direct access register, PWM is not changing polarity it is always high.
When I replace it software drive code, code manage to load counter from phase register, But still I do not have stable output from PWM. It is still lock on high level.

My register values;
PHSEN : 1(Load counter from phase reg. when synchronization pulse is occured)
PHSDIR : 1 (Count up after synchronization)
SYNCOSEL : 0 (EPWMxSYNC)
SWFSYNC : 1 (Enable)
CTRMODE : 2(up-down count)
TBPHS : 0 (Phase value)
PWM frequency : 20KHz

I need immediate help.

Regards
Fahri

Fahri,

Are you checking for the trip behavior while the device is free-running or while halted?

Can you describe how you have the Action-Qualifier and Trip-Zone modules configured?

-Tommy

Hi Tommy

Thank you for your interest.

Analog comparator is connected to the tripzone submodule. Input of the analag comp. is sin wave and inverting input is connected to the DAC. When comp. is high, TZ interrupt occures and in interrupt, it is calculating comparator low level time. After that, it sets itself for comparator low level interrupt to get interrupt onec for same level.

While I check for free run, I observe PWM does not change polarity. It is always high.

If I check it with break point, sometimes it goes low.

Here is my PWM configuration

void InitEPwm1Example()
	{

	    CLK_enablePwmClock(myClk, PWM_Number_1);

	    // Setup TBCLK
	    //PWM_setPeriod(myPwm1, EPWM1_TIMER_TBPRD);   // Set timer period 801 TBCLKs
	    EPwm1Regs.TBPRD=2500;		//set initial pwm frequency 20KHz
	    //PWM_setPhase(myPwm1, 0x0000);               // Phase is 0
	    EPwm1Regs.TBPHS.half.TBPHS=0;				//phase reg is 0
	    //PWM_setCount(myPwm1, 0x0000);               // Clear counter
	    EPwm1Regs.TBCTR=0;          //reset pwm counter

	    //PWM_setCmpA(myPwm1, 1250); //%50 duty cycle olacak şekilde ayarlandı.
 	    //PWM_setCmpB(myPwm1, 1250); //%50 duty cycle olacak şekilde ayarlandı.
 	    EPwm1Regs.CMPA.half.CMPA=1250;
 	    EPwm1Regs.CMPB=1250;

	    // Setup counter mode
	    PWM_setCounterMode(myPwm1, PWM_CounterMode_UpDown); // Count up&down
	    //PWM_disableCounterLoad(myPwm1);                     // Disable phase loading
	    //Enable Phase loading
	    EPwm1Regs.TBCTL.bit.PHSEN=1; 		//load TBC with phase reg. when EPWMSYNI input occure PHSEN 1 yapınca PWM çalışmıyor.
	    EPwm1Regs.TBCTL.bit.PHSDIR=1;		//Set as up counting when phase register load counter
	    EPwm1Regs.TBCTL.bit.SYNCOSEL=TB_SYNC_IN;

	    PWM_setHighSpeedClkDiv(myPwm1, PWM_HspClkDiv_by_1); // Clock ratio to SYSCLKOUT
	    PWM_setClkDiv(myPwm1, PWM_ClkDiv_by_1);

	    //Setup shadowing, shadowing allows the register update to be synchronized with the hardware, shadow register provides a temporary holding location for the active register
	    PWM_setShadowMode_CmpA(myPwm1, PWM_ShadowMode_Shadow);		//Enable shadow mode
	    PWM_setShadowMode_CmpB(myPwm1, PWM_ShadowMode_Shadow);
	    PWM_setLoadMode_CmpA(myPwm1, PWM_LoadMode_Zero);			//Load CMP when TBCTR=0
	    PWM_setLoadMode_CmpB(myPwm1, PWM_LoadMode_Zero);

	    // Set actions
	    PWM_setActionQual_CntUp_CmpA_PwmA(myPwm1, PWM_ActionQual_Set);      // Set PWM1A on event A, up count
	    PWM_setActionQual_CntDown_CmpA_PwmA(myPwm1, PWM_ActionQual_Clear);  // Clear PWM1A on event A, down count

	    PWM_setActionQual_CntUp_CmpA_PwmB(myPwm1, PWM_ActionQual_Clear);      // Clear PWM1B on event B, up count
	    PWM_setActionQual_CntDown_CmpA_PwmB(myPwm1, PWM_ActionQual_Set);  // Set PWM1B on event B, down count

	    //CmpA ve CmpB birbirinin tersi olması için "clear" ve "set" flagleri yer değiştirildi.(cmpB'deki değiştirildi.)

	    // Active high complementary PWMs - Setup the deadband
	    PWM_setDeadBandOutputMode(myPwm1, PWM_DeadBandOutputMode_EPWMxA_Rising_EPWMxB_Falling);
	    PWM_setDeadBandPolarity(myPwm1, PWM_DeadBandPolarity_EPWMxB_Inverted);
	    PWM_setDeadBandInputMode(myPwm1, PWM_DeadBandInputMode_EPWMxA_Rising_and_Falling);
	    //PWM_setDeadBandRisingEdgeDelay(myPwm1, 250);  //RED=2.5us(250)
	    //PWM_setDeadBandFallingEdgeDelay(myPwm1, 250); //FED=2.5us(250)
	    EPwm1Regs.DBRED=0;
	    EPwm1Regs.DBFED=0;

	    // Enable DCAEVT1 and DCBEVT1 are one shot trip sources
	    //PWM_enableTripZoneSrc(myPwm1, PWM_TripZoneSrc_OneShot_CmpA);
	    //PWM_enableTripZoneSrc(myPwm1, PWM_TripZoneSrc_OneShot_CmpB);

	    // What do we want the DCAEVT1 and DCBEVT1 events to do?
	    // DCAEVTx events can force EPWMxA
	    // DCBEVTx events can force EPWMxB
	    PWM_setTripZoneState_TZA(myPwm1, PWM_TripZoneState_DoNothing);  // EPWM1A will do nothing
	    PWM_setTripZoneState_TZB(myPwm1, PWM_TripZoneState_DoNothing);   // EPWM1B will do nothing

	    // Enable TZ interrupt
	    PWM_enableTripZoneInt(myPwm1, PWM_TripZoneFlag_OST);

	    // Interrupt where we will change the Compare Values
	    PWM_setIntMode(myPwm1, PWM_IntMode_CounterEqualZero);   // Select INT on Zero event
	    PWM_enableInt(myPwm1);                                  // Enable INT
	    PWM_setIntPeriod(myPwm1, PWM_IntPeriod_ThirdEvent);     // Generate INT on 3rd event

	    // Information this example uses to keep track
	    // of the direction the CMPA/CMPB values are
	    // moving, the min and max allowed values and
	    // a pointer to the correct ePWM registers
	    epwm1_info.EPwm_CMPA_Direction = EPWM_CMP_UP;   // Start by increasing CMPA &
	    epwm1_info.EPwm_CMPB_Direction = EPWM_CMP_DOWN; // decreasing CMPB
	    epwm1_info.EPwmTimerIntCount = 0;               // Zero the interrupt counter
	    epwm1_info.myPwmHandle = myPwm1;                // Set the pointer to the ePWM module

	}

and tripzone configuration

        EALLOW;
        EPwm1Regs.DCTRIPSEL.bit.DCAHCOMPSEL = DC_COMP2OUT;   // DCAH = Comparator 2 output
        EPwm1Regs.DCTRIPSEL.bit.DCALCOMPSEL = DC_TZ2;        // DCAL = TZ2
        EPwm1Regs.TZDCSEL.bit.DCAEVT1 = TZ_DCAH_HI;   //generates event for comparator high for initialization
        EPwm1Regs.DCACTL.bit.EVT1SRCSEL = DC_EVT1;    //unfiltered signal
        EPwm1Regs.DCACTL.bit.EVT1FRCSYNCSEL = DC_EVT_ASYNC;
        EPwm1Regs.TZSEL.bit.DCAEVT1 = 1;
        //EPwm1Regs.TZSEL.bit.DCBEVT1 = 1;
        EDIS;

And this one is what I am doing in interrupt

interrupt void epwm1_tzint_isr(void)
	{

	    //GPIO_toggle(myGpio, GPIO_Number_6);
	    /*EALLOW;
	    GpioDataRegs.GPASET.bit.GPIO28=0;  //set high
	    EDIS;*/
	    // Clear the flags - we will continue to take
	    // this interrupt until the TZ pin goes high

/*	    EALLOW;
	    CpuTimer0Regs.TCR.bit.TSS = 1; //Stop timer
	    EDIS;
*/
	    //#########################################
	    //##### Adjust Tripzone interrupt condition
	    //#########################################
	    if (EPwm1Regs.TZDCSEL.bit.DCAEVT1==2)
	    	{
	    	EALLOW;
	    	EPwm1Regs.TZDCSEL.bit.DCAEVT1 = 1;
	    //GpioDataRegs.GPASET.bit.GPIO6=1;  //set high
		 //t1=TIMER_getCount(myTimer);
		 t2=65535-CpuTimer0Regs.TIM.all;
		 CpuTimer0Regs.TCR.bit.TRB = 1;  //Timer reload
	    	EDIS;
	    	}
	    else if (EPwm1Regs.TZDCSEL.bit.DCAEVT1==1)
    		{
    		EALLOW;
    		EPwm1Regs.TZDCSEL.bit.DCAEVT1 = 2;
    	        //GpioDataRegs.GPACLEAR.bit.GPIO6=1;  //set low
    	        //t2=TIMER_getCount(myTimer);
    	        t1=65535-CpuTimer0Regs.TIM.all;
    	        CpuTimer0Regs.TCR.bit.TRB = 1;  //Timer reload
    		EDIS;
    		}

	    //digital PLL için (bu kısım incelenecek)
	    tpwm=(t1+t2)>>1;
	    //EPwm1Regs.TBPRD=tpwm;		//update pwm frequency
	    //EPwm1Regs.TBCTL.bit.PRDLD=1;
	    EPwm1Regs.TBCTL.bit.SWFSYNC=1;
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    asm (" NOP");
	    //PWM_forceSync(myPwm1);

		n[EPwm1TZIntCount] = EPwm1Regs.TBSTS.all;
	    EPwm1TZIntCount++;
	    if (EPwm1TZIntCount==150)
	    {
	    	EPwm1TZIntCount = 0;
	    }

I can see that SWFSYNC is working ofter adding asm("NOP")

But still I have no PWM output.

Fahri,

Are you clearing the OST trip in the ISR?

Can you check the contents of the TZCTL register and make sure that the only enabled actions are the ones that you want?

It looks like you are modifying your TZDCSEL trip conditions in the ISR. If you can you attach some figures to illustrate what you want the EPWM outputs to do relative to the comparator input we might be able to give you some recommendations so that the TZDCSEL updates are not necessary.

Also, it may be a good idea to incrementally build your EPWM configuration starting with just one EPWM output signal and no dead-band. Each feature has the potential to break the EPWM output if something is not configured correctly.

-Tommy