The mikroPascal PRO for PIC 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).

Library Routines

• Sound_Init
• Sound_Play

Sound_Init

Sound_Init(PORTC, 3);  // Initialize sound at RC3

Sound_Play

Prototype	procedure Sound_Play(freq_in_hz, duration_ms : word);
Returns	Nothing.
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)   Note : Frequency range is limited by Delay_Cyc parameter. Maximum frequency that can be produced by this function is Freq_max = Fosc/(80*3). Minimum frequency is Freq_min = Fosc/(80*255). Generated frequency may differ from the freq_in_hz parameter due to integer arithmetics.
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);

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

  ANSEL  := 0;                       // Configure AN pins as digital I/O
  ANSELH := 0;
  
  C1ON_bit := 0;                     // Disable comparators
  C2ON_bit := 0;
  
  TRISB  := 0xF8;                    // Configure RB7..RB3 as input

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

  while TRUE do                          // endless loop
    begin
      if (Button(PORTB,7,1,1)) then      // If PORTB.7 is pressed play Tone3
        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 Tone2
        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 Melody2
        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 Melody
          begin
            Melody();
            while (RB3_bit <> 0) do nop; // Wait for button to be released
          end;
    end;
end.

HW Connection

Example of Sound Library connection

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