Audio Sampling mit Arduino DUE und ADC

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include "arduinoFFT.h"

arduinoFFT FFT = arduinoFFT(); /* Create FFT object */

#define  DEBUG_INP          (0)

#define  DEBUG_OUT          (1)

#define OUT_Canel          (16)

#define FFT_Samples        (64)

#define OPT_Half          (2046)

double vReal[FFT_Samples];

double vImag[FFT_Samples];

char  sTemp[80];

void setup()

{

  Serial.begin(115200);

  while(!Serial);

  Serial.println("Ready");

  //--------------------------------------------

  // Init Register

  // setup mode register

  //analogReadResolution(12);

  ADC->ADC_MR = ADC_MR_FREERUN_ON | ADC_MR_SLEEP_NORMAL | ADC_MR_FWUP_OFF;

  ADC->ADC_MR |= ADC_MR_LOWRES_BITS_12;

  ADC->ADC_MR |= ADC_MR_STARTUP_SUT512; // startup time as per default

  ADC->ADC_MR |= ADC_MR_PRESCAL(168); // set clock prescalar to run as fast as possible

  ADC->ADC_MR |= ADC_MR_SETTLING_AST3; //settling time if the analog chanel is switched (dosn't mater if ANACH is not set)

  ADC->ADC_MR |= ADC_MR_ANACH_NONE;

  ADC->ADC_MR |= ADC_MR_TRACKTIM(0); // minimal tracking time

  ADC->ADC_MR |= ADC_MR_TRANSFER(0); // minimal transfer time

  // enable channel

  ADC->ADC_CHER = ADC_CHER_CH7 | ADC_CHER_CH6; //enable ADC on pin A0 (channel 7) + A1}

  delay(10); // wait for init adc

}

void loop() {

#if DEBUG_INP

  Serial.print("InpData:");

#endif

  int value = 0;

  while(ADC->ADC_ISR == ADC_ISR_EOC6);  // warte bis Messung fertig

  for (int i = 0; i < FFT_Samples; i++) { // Alle Samples Messen

#if DEBUG_INP

    if (i % 8 == 0)

      Serial.println("");

#endif

    // Read ADC

    while(ADC->ADC_ISR == ADC_ISR_EOC6);  // warte bis Messung fertig

    value = (int)ADC->ADC_CDR[6];          // Lese A1

    vReal[i] = ((value - OPT_Half) / 25.6f); // Copy to bins after compressing +-80.000

    vImag[i] = 0;     

#if DEBUG_INP

    sprintf(sTemp, "%++05ld,", (long)(vReal[i]));

    //sprintf(sTemp, "%++05ld,", value);

    Serial.print(sTemp);

#endif

  }

#if DEBUG_INP

  Serial.println("");

#endif

  //--------------------------------------------

  // Calc FFT

  int iData[16];

  FFT.Windowing(vReal, FFT_Samples, FFT_WIN_TYP_HAMMING, FFT_FORWARD);

  FFT.Windowing(vReal, FFT_Samples, FFT_WIN_TYP_HAMMING, FFT_FORWARD);

  FFT.Compute(vReal, vImag, FFT_Samples, FFT_FORWARD);

  FFT.ComplexToMagnitude(vReal, vImag, FFT_Samples);

  //double peak = FFT.MajorPeak(vReal, FFT_Samples, SAMPLING_FREQUENCY);

  int iStep = (FFT_Samples / 2) / OUT_Canel; 

  for(int i = 0, j = 0; i < (FFT_Samples / 2); i += iStep) {

    iData[j] = 0;

    for (int k=0 ; k < iStep ; k++) 

      iData[j] += vReal[i+k];

    iData[j] /= iStep; 

    j++;

  }

  FFT.Windowing(vReal, FFT_Samples ,FFT_WIN_TYP_BLACKMAN_HARRIS, FFT_FORWARD);  /* Weigh data */

  FFT.Compute(vReal, vImag, FFT_Samples , FFT_FORWARD); /* Compute FFT */

  FFT.ComplexToMagnitude(vReal, vImag, FFT_Samples ); /* Compute magnitudes */

  //FFT.MajorPeak(vReal, FFT_Samples , samplingFrequency, &x, &v);

  //--------------------------------------------

  // Werte Anzeigen

#if DEBUG_OUT

  Serial.print("OutData:");

  for(int i = 0; i < OUT_Canel; i++)  {

    sprintf(sTemp, "%+04d|", iData[i]);

    Serial.print(sTemp);

  }

  Serial.println("");

#endif

  delay(100);

}