File content as of revision 0:a6a8578e95af:

#include "noteplayer.h"

float *audioDataBuffer = new float[128];
volatile int bufferPOS = 0;
Ticker SampleTime;

void placeNewSample()
{
    speaker.write(audioDataBuffer[bufferPOS++]); //multiply by POT value for volume.
    bufferPOS = (bufferPOS+1) & 0x07F;
}

void loadBuffer()
{
    printf("Generating sine...\r\n");
    for(int i=0; i<128; i++) {
        audioDataBuffer[i] =((1.0 + sin((double(i)/16.0*6.28318530717959)))/2.0); //formula copied from mbed example
    }
}

note makeNote(unsigned char length, pitchname pitch2make)
{
    note madenote;
    madenote.length = length;
    madenote.pitch = pitch2make;
    return madenote;
}

void playNote(note note2play)
{
    float SPB = 60.0*4.0/(120.0);
    int PlayingFreq = pitch2freq(note2play.pitch);
    if(PlayingFreq == 0) { //rest
        wait((1/(float)note2play.length)*SPB);
    } else {
        int sampleRate = PlayingFreq * 16;
        speaker.period_us(1); //1MHz
        float ticker_period = (float) 1/(sampleRate);
        printf("\r\nTicker Period: %f\tTicker Freq: %f\r\nTarget Freq: %i \r\n\r\n",ticker_period, 1/ticker_period, PlayingFreq);

        SampleTime.attach(&placeNewSample,ticker_period);
        wait((1/(float)note2play.length)*SPB);
        SampleTime.detach();

        printf("\033[A\033[A\033[A\033[A");
    }
}

int pitch2freq(pitchname pitch2switch)
{
    switch(pitch2switch) {
        case rest:
            return 0;
        case D2:
            return 73;
        case Ds2:
            return 78;
        case E2:
            return 82;
        case F2:
            return 87;
        case Fs2:
            return 92;
        case G2:
            return 98;
        case Gs2:
            return 104;
        case A2:
            return 110;
        case As2:
            return 117;
        case B2:
            return 123;
        case C3:
            return 131;
        case Cs3:
            return 139;
        case D3:
            return 147;
        case Ds3:
            return 156;
        case E3:
            return 165;
        case F3:
            return 175;
        case Fs3:
            return 185;
        case G3:
            return 196;
        case Gs3:
            return 208;
        case A3:
            return 220;
        case As3:
            return 233;
        case B3:
            return 247;
        case C4:
            return 262;
        case Cs4:
            return 277;
        case D4:
            return 294;
        case Ds4:
            return 311;
        case E4:
            return 330;
        case F4:
            return 349;
        case Fs4:
            return 370;

        case G4:
            return 392;

        case Gs4:
            return 415;

        case A4:
            return 440;

        case As4:
            return 466;

        case B4:
            return 494;

        case C5:
            return 523;

        case Cs5:
            return 554;

        case D5:
            return 587;

        case Ds5:
            return 622;

        case E5:
            return 659;

        case F5:
            return 698;

        case Fs5:
            return 740;

        case G5:
            return 784;

        case Gs5:
            return 831;

        case A5:
            return 880;

        case As5:
            return 932;

        case B5:
            return 988;

        case C6:
            return 1047;

        case Cs6:
            return 1109;

        case D6:
            return 1175;

        case Ds6:
            return 1245;

        case E6:
            return 1319;

        case F6:
            return 1397;

        case Fs6:
            return 1480;

        case G6:
            return 1568;

        case Gs6:
            return 1661;

        case END:
            return -1;
    }
}