Sound Library

The mikroPascal PRO for dsPIC30/33 and PIC24 provides a Sound Library to supply users with routines necessary for sound signalization in their applications. Sound generation needs additional hardware, such as piezo-speaker (example of piezo-speaker interface is given on the schematic at the bottom of this page).

Sound_Init

Prototype	procedure Sound_Init(var snd_port, snd_pin: word);
Description	Configures the appropriate MCU pin for sound generation.
Parameters	`snd_port:` sound output port address `snd_pin:` sound output pin
Returns	Nothing.
Requires	Nothing.
Example	// Initialize the pin RD3 for playing sound Sound_Init(PORTD, 3);
Notes	None.

Sound_Play

Prototype	procedure Sound_Play(freq_in_hz, duration_ms: word);
Description	Generates the square wave signal on the appropriate pin.
Parameters	`freq_in_hz:` signal frequency in Hertz (Hz) `duration_ms:` signal duration in miliseconds (ms)
Returns	Nothing.
Requires	In order to hear the sound, you need a piezo speaker (or other hardware) on designated port. Also, you must call Sound_Init to prepare hardware for output before using this function.
Example	// Play sound of 1KHz in duration of 100ms Sound_Play(1000, 100);
Notes	None.

Library Example

The example is a simple demonstration of how to use the Sound Library for playing tones on a piezo speaker.

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program Sound;

procedure Tone1();
  begin
    Sound_Play(659, 250);            // Frequency = 659Hz, duration = 250ms
  end;

procedure Tone2();
  begin
    Sound_Play(698, 250);            // Frequency = 698Hz, duration = 250ms
  end;

procedure Tone3();
  begin
    Sound_Play(784, 250);            // Frequency = 784Hz, duration = 250ms
  end;

procedure Melody();                  // Plays the melody "Yellow house"
  begin
    Tone1(); Tone2(); Tone3(); Tone3();
    Tone1(); Tone2(); Tone3(); Tone3();
    Tone1(); Tone2(); Tone3();
    Tone1(); Tone2(); Tone3(); Tone3();
    Tone1(); Tone2(); Tone3();
    Tone3(); Tone3(); Tone2(); Tone2(); Tone1();
  end;

procedure ToneA();                   // Tones used in Melody2 function
  begin
    Sound_Play( 880, 50);
  end;

procedure ToneC();
  begin
    Sound_Play(1046, 50);
  end;

procedure ToneE();
  begin
    Sound_Play(1318, 50);
  end;

procedure Melody2();                 // Plays Melody2
var counter : byte;
  begin
    for counter := 9 downto 1 do
      begin
        ToneA();
        ToneC();
        ToneE();
      end;
  end;

begin

  ADPCFG := 0xFFFF;                      // Configure AN pins as digital I/O
  
  TRISB  := 0xF8;                        // Configure RB7..RB3 as input

  Sound_Init(PORTD, 3);
  Sound_Play(880, 1000);

  while TRUE do                          // endless loop
    begin
      if (Button(PORTB,7,1,1)) then      // If PORTB.7 is pressed play Tone1
        begin
          Tone1();
          while (RB7_bit <> 0) do nop;   // Wait for button to be released
        end;

      if (Button(PORTB,6,1,1)) then      // If PORTB.6 is pressed play Tone1
        begin
          Tone2();
          while (RB6_bit <> 0) do nop;   // Wait for button to be released
        end;

      if (Button(PORTB,5,1,1)) then      // If PORTB.5 is pressed play Tone1
        begin
          Tone3();
          while (RB5_bit <> 0) do nop;   // Wait for button to be released
        end;

      if (Button(PORTB,4,1,1)) then      // If PORTB.4 is pressed play Tone1
        begin
          Melody2();
          while (RB4_bit <> 0) do nop;   // Wait for button to be released
        end;

      if (Button(PORTB,3,1,1)) then      // If PORTB.3 is pressed play Tone1
          begin
            Melody();
            while (RB3_bit <> 0) do nop; // Wait for button to be released
          end;
    end;
end.

HW Connection

Example of Sound Library

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