dsPIC30F4013, ADC macht Probleme

void Init_ADC(void)

{

        //ADCON1 Register

        //Set up A/D for Automatic Sampling

        //Use Timer3 to provide sampling time

        //Set up A/D conversrion results to be read in 1.15 fractional

        //number format.

        //All other bits to their default state

        ADCON1bits.FORM = 3;

        ADCON1bits.SSRC = 2;

        ADCON1bits.ASAM = 1;

        //ADCON2 Register

         ADCON2bits.VCFG = 0;         //Internal V+ / V-

     ADCON2bits.SMPI = 15;      //Set up A/D for interrupting after 16 samples get filled in the buffer  

        //ADCON3 Register

        //Total Conversion Time= 1/Sampling Rate = 100 microseconds

        //For fosc=117.968MHz, Tcy = 33.91 ns = Instruction Cycle Time

        //We will set up Sampling Time using Timer3 & Tad using ADCS<5:0> bits

        //All other bits to their default state

        //Let's set up ADCS arbitrarily to 38

        //So Tad = Tcy*(ADCS+1)/2 = 661.2 nanoseconds

        //So, the A/D converter will take 14*Tad periods to convert each sample

        ADCON3bits.ADCS = 38;

        //Set up Timer 3 Trigger

        TMR3 = 0x0000;      

      PR3 = 0x0BAF;

    IFS0bits.T3IF = 0;

        IEC0bits.T3IE = 0;

    T3CONbits.TCS = 0;

    T3CONbits.TCKPS=0;

        //ADCHS Register

        //Set up A/D Channel Select Register to convert AN5 on Mux A input

        ADCHS = 0x0005;

      //ADCSSL Register

        //Channel Scanning is disabled. All bits left to their default state

        ADCSSL = 0x0000;

        //ADPCFG Register

        //Set up channels AN5 as analog inputs and configure rest as digital

        //entered main() out of reset

        ADPCFG = 0xFFFF;

        ADPCFGbits.PCFG5 = 0;

        //Clear the A/D interrupt flag bit

        IFS0bits.ADIF = 0;

        //Set the A/D interrupt enable bit

        IEC0bits.ADIE = 1;

        //Turn on the A/D converter

        //This is typically done after configuring other registers

        ADCON1bits.ADON = 1;

        //Start Timer 3

        T3CONbits.TON = 1;

}

void __attribute__((__interrupt__)) _ADCInterrupt(void)

{

        //Clear the Timer3 Interrupt Flag

        IFS0bits.T3IF = 0;

        int i = 0;

        //Clear the A/D Interrupt flag bit or else the CPU will

        //keep vectoring back to the ISR

        IFS0bits.ADIF = 0;

        //Put the A/D conversion results to sigCmpx.real

        adcPtr = &ADCBUF0 ;

    for (i=0;i<16;i++)

          {

         (*p_sigCmpx).imag = 0x0000;

               (*p_sigCmpx++).real = *adcPtr++;         

      }

    if (p_sigCmpx > &sigCmpx[FFT_BLOCK_LENGTH-1])

      {

       SamplesReadyFlag ++;   // Sampling completed

         IEC0bits.ADIE = 0;    // Disable ADC interrupt

      }  

}