TMS570LS0714: ADC Stuck in conversation while loop

I am trying to read voltage by using adc in TMS570lS07 and i have done all the intructions in (ADC Display)help topic but my ADC did not work and stucks in  while((adcIsConversionComplete(adcREG1,adcGROUP1))==0); also the flag there has 0 as return value so can any one tell us how can we solve this problem ??

#include "sys_common.h"
#include "system.h"

#include "esm.h"
#include "adc.h"
#include "gio.h"
#include "het.h"




adcData_t adc_data[4];
void wait(uint32 time);



void main(void)
{
    uint32 ch_count=0;

    gioInit();
    hetInit(),
    adcInit();


    while(1) /* ... continue forever */
    {


        adcStartConversion(adcREG1,adcGROUP1);


        /* ... wait and read the conversion count */
        while((adcIsConversionComplete(adcREG1,adcGROUP1))==0);
        ch_count = adcGetData(adcREG1, adcGROUP1,&adc_data[0]);

        ch_count = ch_count;

    }
}


void wait(uint32 time)
{
    while(time){time--;};
}