File content as of revision 5:49c961e79a12:

#include "beep.h"
#include "mbed.h"
#include "notes.h"

/** class to make sound with a buzzer, based on a PwmOut
 *   The class use a timeout to switch off the sound  - it is not blocking while making noise
 *
 * Example:
 * @code
 * // Beep with 1Khz for 0.5 seconds
 * #include "mbed.h"
 * #include "beep.h"
 * 
 * Beep buzzer(p21);
 * 
 * int main() {
 *       ...
 *   buzzer.beep(1000,0.5);    
 *       ...
 * }
 * @endcode
 */

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
};


using namespace mbed;
 // constructor
 /** Create a Beep object connected to the specified PwmOut pin
  *
  * @param pin PwmOut pin to connect to 
  */
    
Beep::Beep(PinName pin) : _pwm(pin) {
    _pwm.write(0.0);     // after creating it have to be off
}

 /** stop the beep instantaneous 
  * usually not used 
  */
void Beep::nobeep() {
    _pwm.write(0.0);
}

/** Beep with given frequency and duration.
 *
 * @param frequency - the frequency of the tone in Hz
 * @param time - the duration of the tone in seconds
 */
     
void Beep::beep(float freq, float time) {

    _pwm.period(1.0/freq);
    _pwm.write(0.5);            // 50% duty cycle - beep on
    toff.attach(this,&Beep::nobeep, time);   // time to off
}


void Beep::playRttl(char *p){
  char default_dur = 4;
  char default_oct = 6;
  int bpm = 63;
  int num;
  long wholenote;
  long duration;
  char note;
  char 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
  }


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


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


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


  // 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 += OCTAVE_OFFSET;

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

    // now play the note

    if(note)
    {
      beep(notes[(scale - 4) * 12 + note], (float)duration/1000);
      wait((float)duration/1000);
    }
    else
    {
      //wait((float)duration/1000);
    }
  }
}