usb and temperature sensor

Hi,

I want to read value of embedded temperature sensor on TM4C123Gh6PH. I used usb_dev_serial.c example and added following lines to read chip temperature.

When I programmed the code, it is working but when I disconnected power of the device and power up it again, the usb connection is known as “unknown device”. Can anybody help me to figure out where the problem is?

 Thanks

SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);

                    ADCSequenceConfigure(ADC0_BASE, 1, ADC_TRIGGER_PROCESSOR, 0);

                    ADCSequenceStepConfigure(ADC0_BASE, 1, 0, ADC_CTL_TS);

                    ADCSequenceStepConfigure(ADC0_BASE, 1, 1, ADC_CTL_TS);

                    ADCSequenceStepConfigure(ADC0_BASE, 1, 2, ADC_CTL_TS);

                    ADCSequenceStepConfigure(ADC0_BASE,1,3,ADC_CTL_TS|ADC_CTL_IE|ADC_CTL_END);

                    ADCSequenceEnable(ADC0_BASE, 1);

                    uint32_t ui32ADC0Value[4];

                    volatile uint32_t ui32TempAvg;

                    volatile uint32_t ui32TempValueC;

                    volatile uint32_t ui32TempValueF;

    while(1)

    {

       ADCIntClear(ADC0_BASE, 1);

       ADCProcessorTrigger(ADC0_BASE, 1);

       while(!ADCIntStatus(ADC0_BASE, 1, false))

       {

       }

       ADCSequenceDataGet(ADC0_BASE, 1, ui32ADC0Value);

       ui32TempAvg = (ui32ADC0Value[0] + ui32ADC0Value[1] + ui32ADC0Value[2] + ui32ADC0Value[3] + 2)/4;

       ui32TempValueC = (1475 - ((2475 * ui32TempAvg)) / 4096)/10;

       ui32TempValueF = ((ui32TempValueC * 9) + 160) / 5;

}