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Why can I only save 256 ADC samples?

Other Parts Discussed in Thread: MSP430F5529, MSP-EXP430F5529LP

Hi everyone,


I'm starting with TI example code for repeated conversions on a single channel using "repeat-single-channel" mode.  The only change that I've made is changing the #define Num_of_Results from 8 to 500.  Anything greater than 500 causes issues, but that is a secondary problem right now.  

When i debug the code I connect a function generator to my MSP430 and look at the values in the results array.  I have values from 0 to 255 but every value after that is just 0.  What can I do to fill up the whole array?  I want this code to record 30-60 seconds of audio and I'm going to need more than 256 samples (and more than 500 samples for that matter).  I have pasted the code below, does anybody see what I am doing wrong?


Thank you.

#include <msp430.h>

#define   Num_of_Results   500
 
volatile unsigned int results[Num_of_Results];
                                            // Needs to be global in this
                                            // example. Otherwise, the
                                            // compiler removes it because it
                                            // is not used for anything.

int main(void)
{
  WDTCTL = WDTPW+WDTHOLD;                   // Stop watchdog timer
  P6SEL |= 0x01;                            // Enable A/D channel A0
  ADC12CTL0 = ADC12ON+ADC12SHT0_8+ADC12MSC; // Turn on ADC12, set sampling time
                                            // set multiple sample conversion
  ADC12CTL1 = ADC12SHP+ADC12CONSEQ_2;       // Use sampling timer, set mode
  ADC12IE = 0x01;                           // Enable ADC12IFG.0
  ADC12CTL0 |= ADC12ENC;                    // Enable conversions
  ADC12CTL0 |= ADC12SC;                     // Start conversion
 
  __bis_SR_register(LPM4_bits + GIE);       // Enter LPM4, Enable interrupts
  __no_operation();                         // For debugger
 
}


#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR (void)
{
  static unsigned char index = 0;

  switch(__even_in_range(ADC12IV,34))
  {
  case  0: break;                           // Vector  0:  No interrupt
  case  2: break;                           // Vector  2:  ADC overflow
  case  4: break;                           // Vector  4:  ADC timing overflow
  case  6:                                  // Vector  6:  ADC12IFG0
    results[index] = ADC12MEM0;             // Move results
    index++;                                // Increment results index, modulo; Set Breakpoint1 here
   
    if (index == Num_of_Results)
    {
      index = 0;
    }
  case  8: break;                           // Vector  8:  ADC12IFG1
  case 10: break;                           // Vector 10:  ADC12IFG2
  case 12: break;                           // Vector 12:  ADC12IFG3
  case 14: break;                           // Vector 14:  ADC12IFG4
  case 16: break;                           // Vector 16:  ADC12IFG5
  case 18: break;                           // Vector 18:  ADC12IFG6
  case 20: break;                           // Vector 20:  ADC12IFG7
  case 22: break;                           // Vector 22:  ADC12IFG8
  case 24: break;                           // Vector 24:  ADC12IFG9
  case 26: break;                           // Vector 26:  ADC12IFG10
  case 28: break;                           // Vector 28:  ADC12IFG11
  case 30: break;                           // Vector 30:  ADC12IFG12
  case 32: break;                           // Vector 32:  ADC12IFG13
  case 34: break;                           // Vector 34:  ADC12IFG14
  default: break;
  }
}

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