CCS/TMS320F280049C: HRPWM phase shift, unable to get microsteps

Tool/software: Code Composer Studio

Hello,

I am trying to implement the HR PWM phase shift for my application. With normal EPWM is working, but I would need higher resolution. Here is the code that I am using:

void PSFB_HAL_setupHRPWM(uint32_t PWMbase)

{

    MEP_ScaleFactor = 55;

    //Number of MEP steps per coarse step at 180 ps (10 n/180 ps ), MEP_ScaleFactor
    HRPWM_setMEPStep(PWMbase, MEP_ScaleFactor);

    //
    // HRCAL uses the EPWM1 clock
    //
    SysCtl_enablePeripheral(SYSCTL_PERIPH_CLK_EPWM1);

    HRPWM_enableAutoConversion(PWMbase);

    //Setting MEP
    HRPWM_setMEPEdgeSelect(PWMbase, HRPWM_CHANNEL_A, HRPWM_MEP_CTRL_RISING_AND_FALLING_EDGE);
    HRPWM_setMEPControlMode(PWMbase, HRPWM_CHANNEL_A, HRPWM_MEP_PHASE_CTRL);//HRPWM_MEP_DUTY_PERIOD_CTRL);

    //HRPWM_setSyncPulseSource(PWMbase, HRPWM_PWMSYNC_SOURCE_ZERO);

    //HRPWM_enablePeriodControl(PWMbase);
    //HRPWM_setTimeBasePeriod(PWMbase, PSFB_EPWM_TBPRD);
    //HRPWM_setHiResTimeBasePeriodOnly(PWMbase, frac(PSFB_EPWM_TBPRD) << 8);

    //
    // Align HRPWM CMPA value and shadow mode with EPWM
    //
    HRPWM_setCounterCompareShadowLoadEvent(PWMbase, HRPWM_CHANNEL_A, HRPWM_LOAD_ON_CNTR_ZERO);

    HRPWM_setCounterCompareValue(PWMbase, HRPWM_COUNTER_COMPARE_A, 0);
    HRPWM_setHiResCounterCompareValueOnly(PWMbase, HRPWM_COUNTER_COMPARE_A, 0);

    HRPWM_setChannelBOutputPath(PWMbase, HRPWM_OUTPUT_ON_B_NORMAL);

    HRPWM_setPhaseShift(PWMbase, 0);
    HRPWM_setHiResPhaseShiftOnly(PWMbase, 0);

}

In main:

    HRPWM_enablePhaseShiftLoad(PSFB2_DRV_EPWM_BASE);
    HRPWM_enablePhaseShiftLoad(PSFBR_DRV_EPWM_BASE);

    EPWM_enablePhaseShiftLoad(PSFB2_DRV_EPWM_BASE);
    EPWM_enablePhaseShiftLoad(PSFBR_DRV_EPWM_BASE);

for(;;)

{

Phase_shift = PSFB_shift / 360; //Where PSFB_shift varies from 0 to 360.

         HRPWM_setPhaseShift(PSFB2_DRV_EPWM_BASE, (uint32_t)((Phase_shift * PSFB_EPWM_TBPRD) * ((uint16_t)0x1 << 8)));

}

PSFB_shift is updated every 10Hz:

    if(PSFB_shift <=45)
        PSFB_shift= 300;

    PSFB_shift = PSFB_shift - 0.01f;

What I get on the output is that the signal is shifting to the left by microsteps, very small steps, and then, suddenly jumping to the right with 4ns step. So doing the shift to the other direction and recovering what it has done to the left plus additional "jump"... I try to add a video of the oscilloscope.

Thank you very much.

Luis