File content as of revision 0:6b0b61d411ad:

//    Guitar Tuner and Chord Learning Tool using Goertzel's Algorithm     //
//    Based on original code created by: Andrew Durand                   //
//    Adjusted and modified by Tapton School EDS Project Team            //

#include "TextLCD.h"
#include "mbed.h"
#include "adc.h"
#include <math.h>
#define PI 3.1415
#define SAMPLE_RATE 24000

DigitalOut led_low(LED1);
DigitalOut led_ok(LED2);
DigitalOut led_high(LED4);
InterruptIn button1(p6); //mosi
DigitalIn myInputPin (p21); //select tuner or chord learning mode

//LCD and Other Random Variables
//NokiaLCD lcd(p5, p7, p8, p9, NokiaLCD::LCD6610); // mosi, sclk, cs, rst, type

/* This code uses libraries created for 4-bit LCD's based on the HD44780. This 
program was designed for a similar product (Winstar's WH1602B 2x16 LC) working 
into an Mbed LPC1768. 
LCD pins: Pin 1(VSS) to Mbed Gnd, Pin 2(VDD) to Mbed 5v USB output, Pin 3(Vo- contrast)
to Mbed Gnd (via a 4k7 resistor), Pin 5(R/W) to Mbed Gnd, Pin 15(A)to Mbed 5v USB output, Pin 16(B) to 
MBed Gnd,  Pins 4(RS),20(E) and the 4 data bits (DB4 [11] through to DB7 [14])
go to the Mbed pins described below: */   

TextLCD lcd(p10, p12, p15, p16, p29, p30); // rs, e, d4-d7
 
int string_select = 0;
int chord_select = 0;
float high, high1, in_tune, in_tune1, in_tune2, in_tune3,
low, low1, note, low_mod, high_mod;
char* key;
int Counter = 0;
int Buffer[6000];

float goertzelFilter(int samples[], float freq, int N) {
    float s_prev = 0.0;
    float s_prev2 = 0.0;
    float coeff,normalizedfreq,power,s;
    int i;
    normalizedfreq = freq / SAMPLE_RATE;
    coeff = 2*cos(2*PI*normalizedfreq);
    for (i=0; i<N; i++) {
        s = samples[i] + coeff * s_prev - s_prev2;
        s_prev2 = s_prev;
        s_prev = s;
    }
    power = s_prev2*s_prev2+s_prev*s_prev-coeff*s_prev*s_prev2;
    return power;
}

ADC adc(SAMPLE_RATE, 1);

void sample_audio(int chan, uint32_t value) {
    Buffer[Counter] = adc.read(p20);
    Counter += 1;
}

void button1_pressed() {
    string_select++;
    chord_select++;
    if (string_select > 5) string_select = 0;
    if (chord_select > 9) chord_select = 0;//change for number of chords supported
}

int main() {
  while (1) {
     myInputPin.mode(PullUp);  //set the mbed to use a pullup resistor
     if (myInputPin) { //select guitar tuner or chord teaching
        lcd.cls (); // Guitar Tuner Section based on p21 being +3v
     
        //Interupt for Switching Strings
        button1.mode(PullDown);
        button1.rise(&button1_pressed);

        while (1) {

              switch (string_select) {
              case 0:
                note = 82;
                key= "E2";
                break;
              case 1:
                note = 110;
                key= "A2";
                break;
              case 2:
                note = 147;
                key= "D3";
                break;
              case 3:
                note = 196;
                key= "G3";
                break;
              case 4:
                note = 247;
                key= "B3";
                break;
              case 5:
                note = 330;
                key= "E4";
                break;
              }

           //Prepare for burst mode on all ADC pins and set up interrupt handler (using ADC library from Simon Blandford
           adc.append(sample_audio);
           adc.startmode(0,0);
           adc.burst(1);
           adc.setup(p20,1);

           //start the interrupt and wait for about 4096 samples
          adc.interrupt_state(p20,1);
          wait(.2);

          //Finsh up - Unset pin 20
          adc.interrupt_state(p20,0);
          adc.setup(p20,0);
          int actual_rate = adc.actual_sample_rate();

          //for debugging tell the terminal sample rate and how many samples we took
          printf("Requested max sample rate is %u, actual max sample rate is %u.\n",
               SAMPLE_RATE, actual_rate);
          printf("We did %i samples\n",Counter);

          high = 0;
          low = 0;
          for (int i=3; i<46; i+=3) {
             high1 = goertzelFilter(Buffer, (note + i ), Counter);
             if (high1 > high) high=high1;
             }
          for (int i=3; i<46; i+=3) {
             low1 = goertzelFilter(Buffer, (note - i ), Counter);
             if (low1 > low) low=low1;
             }
           in_tune1 =  goertzelFilter(Buffer, (note+1), Counter);
           in_tune2 =  goertzelFilter(Buffer, note, Counter);
           in_tune3 =  goertzelFilter(Buffer, (note-1), Counter);
        
          if ((in_tune1 > in_tune2) && (in_tune1 > in_tune3)) in_tune = in_tune1;
          else if ((in_tune2 > in_tune1) && (in_tune2 > in_tune3)) in_tune = in_tune2;
          else in_tune = in_tune3;
 
          if ((in_tune > high) && (in_tune > low)) {
            led_high = 0;
            led_ok = 1;
            led_low = 0;
           } else if (high > in_tune) {
            led_high = 1;
            led_ok = 0;
            led_low = 0;
             } else if (low > in_tune) {
               led_high = 0;
               led_ok = 0;
               led_low = 1;
               } else {
                 led_high = 0;
                 led_ok = 0;
                 led_low = 0;
                 }
        
        int pintwenty = adc.read(p20); //read pin 20
        lcd.locate(0,1);
        lcd.printf("%s %iHz %d\n",key, (int) note, pintwenty);
        if (led_ok) lcd.printf("Tuner- In Tune");
        else if (led_low) lcd.printf("Tuner- 2Low   ");
        else if (led_high) lcd.printf("Tuner- 2High  ");
        else lcd.printf("~~~~~~~~");

        Counter = 0;
        } //inner while (1)loop
      } else {  //if myinputpin
  
      lcd.cls (); //Chord Tutor Section based on p21 being 0v 
     
    //Interupt for Switching chord selection
    button1.mode(PullDown);
    button1.rise(&button1_pressed);



    while (1) {

        switch (chord_select) {
            case 0:
                note = 82;
                key= "E2";
                //send E chord white LED pattern
                break;
            case 1:
                note = 110;
                key= "A2";
                //send A chord white LED pattern
                break;
            case 2:
                note = 147;
                key= "D3";
                //send D chord white LED pattern                
                break;
            case 3:
                note = 196;
                key= "G3";
                //send G chord white LED pattern                
                break;
            case 4:
                note = 247;
                key= "B3";
                //send B chord white LED pattern                
                break;
            case 5:
                note = 2349;
                key= "D7";
                //send D7 chord white LED pattern                
                break;
            case 6:
                note = 131;
                key= "C3";
                //send C chord white LED pattern                
                break;
            case 7:
                note = 174;
                key= "F3";
                //send F chord white LED pattern                
                break;
            case 8:
                note = 65;
                key= "C2";
                //send C chord white LED pattern                
                break;
            case 9:
                note = 87;
                key= "F2";
                //send F chord white LED pattern                
                break;
        }

        //Prepare for burst mode on all ADC pins and set up interrupt handler (using ADC library from Simon Blandford
        adc.append(sample_audio);
        adc.startmode(0,0);
        adc.burst(1);
        adc.setup(p20,1);

        //start the interrupt and wait for about 4096 samples
        adc.interrupt_state(p20,1);
        wait(.2);

        //Finsh up - Unset pin 20
        adc.interrupt_state(p20,0);
        adc.setup(p20,0);
        int actual_rate = adc.actual_sample_rate();

        //for debugging tell the terminal sample rate and how many samples we took
        printf("Requested max sample rate is %u, actual max sample rate is %u.\n",
               SAMPLE_RATE, actual_rate);
        printf("We did %i samples\n",Counter);

high = 0;
low = 0;
for (int i=3; i<46; i+=3) {
    high1 = goertzelFilter(Buffer, (note + i ), Counter);
    if (high1 > high) high=high1;
}
for (int i=3; i<46; i+=3) {
    low1 = goertzelFilter(Buffer, (note - i ), Counter);
    if (low1 > low) low=low1;
}
        in_tune1 =  goertzelFilter(Buffer, (note+1), Counter);
        in_tune2 =  goertzelFilter(Buffer, note, Counter);
        in_tune3 =  goertzelFilter(Buffer, (note-1), Counter);
        
        if ((in_tune1 > in_tune2) && (in_tune1 > in_tune3)) in_tune = in_tune1;
        else if ((in_tune2 > in_tune1) && (in_tune2 > in_tune3)) in_tune = in_tune2;
        else in_tune = in_tune3;
        if ((in_tune > high) && (in_tune > low)) {
            led_high = 0;
            led_ok = 1;
            led_low = 0;
        } else if (high > in_tune) {
            led_high = 1;
            led_ok = 0;
            led_low = 0;
        } else if (low > in_tune) {
            led_high = 0;
            led_ok = 0;
            led_low = 1;
        } else {
            led_high = 0;
            led_ok = 0;
            led_low = 0;
        }
        
    int pintwenty = adc.read(p20); //read pin 20
        lcd.locate(0,1);
        lcd.printf("%s ",key);
        lcd.locate(4,1);// need to deal with lcd screen changes to length of frequencies
        lcd.printf("       ");
        lcd.locate(4,1);
        lcd.printf("%iHz",(int) note); 
        lcd.locate(11,1);
        lcd.printf("%4d\n",pintwenty); //need to deal with lcd screen changes to restrict input decimal range to 4sf
        if (led_ok) lcd.printf("Play %s->In Tune",key); //if statement here for send green LED pattern for selected chord
        else if (led_low) lcd.printf("Play %s -> 2Low ",key);//if statement here for send red LED pattern for selected chord
        else if (led_high) lcd.printf("Play %s -> 2High",key);//if statement here for send red LED pattern for selected chord
        else lcd.printf("~~~~~~~~");

        Counter = 0;
        }
       }
  
  
      }
}