problem with A\D

i have a problem with the A\D i am using  this code 

unsigned long ulValue;
//
// Enable the first sample sequencer to capture the value of channel 0 when
// the processor trigger occurs.
//
ADCSequenceConfigure(ADC0_BASE, 0, ADC_TRIGGER_PROCESSOR, 0);
ADCSequenceStepConfigure(ADC0_BASE, 0, 0,
ADC_CTL_IE | ADC_CTL_END | ADC_CTL_CH0);
ADCSequenceEnable(ADC0_BASE, 0);
//
// Trigger the sample sequence.
//
ADCProcessorTrigger(ADC0_BASE, 0);
//
// Wait until the sample sequence has completed.
//
while(!ADCIntStatus(ADC0_BASE, 0, false))
{
}
//
// Read the value from the ADC.
//
ADCSequenceDataGet(ADC0_BASE, 0, &ulValue);

when i do debbuging and step into the function

ADCSequenceConfigure  

this the code for the function :

void
ADCSequenceConfigure(unsigned long ulBase, unsigned long ulSequenceNum,
                     unsigned long ulTrigger, unsigned long ulPriority)
{
    //
    // Check the arugments.
    //
    ASSERT((ulBase == ADC0_BASE) || (ulBase == ADC1_BASE));
    ASSERT(ulSequenceNum < 4);
    ASSERT((ulTrigger == ADC_TRIGGER_PROCESSOR) ||
           (ulTrigger == ADC_TRIGGER_COMP0) ||
           (ulTrigger == ADC_TRIGGER_COMP1) ||
           (ulTrigger == ADC_TRIGGER_COMP2) ||
           (ulTrigger == ADC_TRIGGER_EXTERNAL) ||
           (ulTrigger == ADC_TRIGGER_TIMER) ||
           (ulTrigger == ADC_TRIGGER_PWM0) ||
           (ulTrigger == ADC_TRIGGER_PWM1) ||
           (ulTrigger == ADC_TRIGGER_PWM2) ||
           (ulTrigger == ADC_TRIGGER_PWM3) ||
           (ulTrigger == ADC_TRIGGER_ALWAYS));
    ASSERT(ulPriority < 4);

    //
    // Compute the shift for the bits that control this sample sequence.
    //
    ulSequenceNum *= 4;

    //
    // Set the trigger event for this sample sequence.
    //
    HWREG(ulBase + ADC_O_EMUX) = ((HWREG(ulBase + ADC_O_EMUX) &
                                   ~(0xf << ulSequenceNum)) |
                                  ((ulTrigger & 0xf) << ulSequenceNum));

    //
    // Set the priority for this sample sequence.
    //
    HWREG(ulBase + ADC_O_SSPRI) = ((HWREG(ulBase + ADC_O_SSPRI) &
                                    ~(0xf << ulSequenceNum)) |
                                   ((ulPriority & 0x3) << ulSequenceNum));
}

i get a FaultISR ,it happens when i get to this line in the function

 HWREG(ulBase + ADC_O_EMUX) = ((HWREG(ulBase + ADC_O_EMUX) &
                                   ~(0xf << ulSequenceNum)) |
                                  ((ulTrigger & 0xf) << ulSequenceNum));