CCS/TMS320F28379D: 1MHz ADC sampling frequency question

Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

I wanted to set the ADC sampling frequency to 1MHz, I used c2000ware driverlib do it, but I only got 500KHz.

Then, I tried to fix it by changing the TBPRD(use EPWM5_SOCA as a trigger), however, no matter what TBPRD I chose, the sampling can't surpass 500KHz.

void ADC_Init(void)
{
    ADC_setPrescaler(ADCA_BASE, ADC_CLK_DIV_4_0);

    ADC_setMode(ADCA_BASE, ADC_RESOLUTION_12BIT, ADC_MODE_SINGLE_ENDED);

    ADC_setInterruptPulseMode(ADCA_BASE, ADC_PULSE_END_OF_CONV);

    ADC_enableConverter(ADCA_BASE);

    DEVICE_DELAY_US(1000);
}

void ADC_SOC_Init(void)
{
    ADC_setupSOC(ADCA_BASE, ADC_SOC_NUMBER0, ADC_TRIGGER_EPWM5_SOCA,ADC_CH_ADCIN0, 15);
    ADC_setInterruptSource(ADCA_BASE, ADC_INT_NUMBER1, ADC_SOC_NUMBER0);
    ADC_enableInterrupt(ADCA_BASE, ADC_INT_NUMBER1);
    ADC_clearInterruptStatus(ADCA_BASE, ADC_INT_NUMBER1);
}


void ADC_EPWM_Init(void)
{    
    EPWM_disableADCTrigger(EPWM5_BASE, EPWM_SOC_A);

    EPWM_setADCTriggerSource(EPWM5_BASE, EPWM_SOC_A, EPWM_SOC_TBCTR_U_CMPA);
    EPWM_setADCTriggerEventPrescale(EPWM5_BASE, EPWM_SOC_A, 1);

    EPWM_setCounterCompareValue(EPWM5_BASE, EPWM_COUNTER_COMPARE_A, 50);
    EPWM_setTimeBasePeriod(EPWM5_BASE, 100);

    // Freeze the counter
    EPWM_setTimeBaseCounterMode(EPWM5_BASE, EPWM_COUNTER_MODE_STOP_FREEZE);

    EPWM_enableADCTrigger(EPWM5_BASE, EPWM_SOC_A);
    EPWM_setTimeBaseCounterMode(EPWM5_BASE, EPWM_COUNTER_MODE_UP);
}