File content as of revision 0:b7dd35e61bb1:

#include "Speaker.h"

static int notes[] = {0,
        NOTE_C4, NOTE_CS4, NOTE_D4, NOTE_DS4, NOTE_E4, NOTE_F4, NOTE_FS4, NOTE_G4, NOTE_GS4, NOTE_A4, NOTE_AS4, NOTE_B4,
        NOTE_C5, NOTE_CS5, NOTE_D5, NOTE_DS5, NOTE_E5, NOTE_F5, NOTE_FS5, NOTE_G5, NOTE_GS5, NOTE_A5, NOTE_AS5, NOTE_B5,
        NOTE_C6, NOTE_CS6, NOTE_D6, NOTE_DS6, NOTE_E6, NOTE_F6, NOTE_FS6, NOTE_G6, NOTE_GS6, NOTE_A6, NOTE_AS6, NOTE_B6,
        NOTE_C7, NOTE_CS7, NOTE_D7, NOTE_DS7, NOTE_E7, NOTE_F7, NOTE_FS7, NOTE_G7, NOTE_GS7, NOTE_A7, NOTE_AS7, NOTE_B7
};

void Speaker::set_frequency(uint32_t frequency) {
    _pwm.period(1.0/frequency);
}

void Speaker::enable(bool enable) {
    *this = enable;
}

Speaker& Speaker::operator=(int setting) {
    if (setting) {
        _pwm = 0.5;
    } else {
        _pwm = 1;
    }
    return *this;    
}

/*
 * Plays an old-school ringtone in RTTTL language.
 */
void Speaker::play_rtttl(char * p) {
  // Absolutely no error checking in here

  uint8_t default_dur = 4;
  uint8_t default_oct = 6;
  int bpm = 63;
  int num;
  long wholenote;
  long duration;
  uint8_t note;
  uint8_t scale;

  // format: d=N,o=N,b=NNN:
  // find the start (skip name, etc)

  while(*p != ':') p++;    // ignore name
  p++;                     // skip ':'

  // get default duration
  if(*p == 'd')
  {
    p++; p++;              // skip "d="
    num = 0;
    while(isdigit(*p))
    {
      num = (num * 10) + (*p++ - '0');
    }
    if(num > 0) default_dur = num;
    p++;                   // skip comma
  }

  printf("ddur: %d\n", default_dur);

  // get default octave
  if(*p == 'o')
  {
    p++; p++;              // skip "o="
    num = *p++ - '0';
    if(num >= 3 && num <=7) default_oct = num;
    p++;                   // skip comma
  }

  printf("doct: %d\n", default_oct);

  // get BPM
  if(*p == 'b')
  {
    p++; p++;              // skip "b="
    num = 0;
    while(isdigit(*p))
    {
      num = (num * 10) + (*p++ - '0');
    }
    bpm = num;
    p++;                   // skip colon
  }

  printf("bpm: %d\n",bpm);

  // BPM usually expresses the number of quarter notes per minute
  wholenote = (60 * 1000L / bpm) * 4;  // this is the time for whole note (in milliseconds)

  printf("wn: %d\n", wholenote);


  // now begin note loop
  while(*p)
  {
    // first, get note duration, if available
    num = 0;
    while(isdigit(*p))
    {
      num = (num * 10) + (*p++ - '0');
    }

    if(num) duration = wholenote / num;
    else duration = wholenote / default_dur;  // we will need to check if we are a dotted note after

    // now get the note
    note = 0;

    switch(*p)
    {
      case 'c':
        note = 1;
        break;
      case 'd':
        note = 3;
        break;
      case 'e':
        note = 5;
        break;
      case 'f':
        note = 6;
        break;
      case 'g':
        note = 8;
        break;
      case 'a':
        note = 10;
        break;
      case 'b':
        note = 12;
        break;
      case 'p':
      default:
        note = 0;
    }
    p++;

    // now, get optional '#' sharp
    if(*p == '#')
    {
      note++;
      p++;
    }

    // now, get optional '.' dotted note
    if(*p == '.')
    {
      duration += duration/2;
      p++;
    }

    // now, get scale
    if(isdigit(*p))
    {
      scale = *p - '0';
      p++;
    }
    else
    {
      scale = default_oct;
    }

    scale += _offset;

    if(*p == ',')
      p++;       // skip comma for next note (or we may be at the end)

    // now play the note

    if(note)
    {
      //printf("\027\033H");
      //printf("Playing: %d %d (%d) %d\n", scale, note, notes[(scale - 4) * 12 + note], duration);
      set_frequency(notes[(scale - 4) * 12 + note]);
      enable(true);
      wait_ms(duration);
      enable(false);
    }
    else
    {
      //printf("Pausing: %d\n", duration);
      wait_ms(duration);
    }
  }
}