The mikroC PRO for AVR 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

// Initialize the pin RC3 for playing sound
Sound_Init(&PORTC, 3);

Sound_Play

Prototype	void Sound_Play(unsigned freq_in_hz, unsigned duration_ms);
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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void Tone1() {
  Sound_Play(659, 250);   // Frequency = 659Hz, duration = 250ms
}

void Tone2() {
  Sound_Play(698, 250);   // Frequency = 698Hz, duration = 250ms
}

void Tone3() {
  Sound_Play(784, 250);   // Frequency = 784Hz, duration = 250ms
}

void Melody() {                              // Plays the melody "Yellow house"
  Tone1(); Tone2(); Tone3(); Tone3();
  Tone1(); Tone2(); Tone3(); Tone3();
  Tone1(); Tone2(); Tone3();
  Tone1(); Tone2(); Tone3(); Tone3();
  Tone1(); Tone2(); Tone3();
  Tone3(); Tone3(); Tone2(); Tone2(); Tone1();
}

void ToneA() {
  Sound_Play( 880, 50);
}
void ToneC() {
  Sound_Play(1046, 50);
}
void ToneE() {
  Sound_Play(1318, 50);
}

void Melody2() {                // Plays Melody2
 unsigned short i;
  for (i = 9; i > 0; i--) {
    ToneA(); 
    ToneC(); 
    ToneE();
    }
}

void main() {

  DDRB = 0x00;                   // Configure PORTB as input
  Sound_Init(&PORTC,3);                  // Initialize sound pin
  
  Sound_Play(880, 1000);         // Play sound at 880Hz for 1 second

  while (1) {                    // endless loop
  
    if (PINB7_bit)               // If PORTB.7 is pressed play Tone1
      Tone1();                   // 
    while (PINB7_bit) ;          // Wait for button to be released

    if (PINB6_bit)               // If PORTB.6 is pressed play Tone2
      Tone2();                   //
    while (PINB6_bit) ;          // Wait for button to be released

    if (PINB5_bit)               // If PORTB.5 is pressed play Tone3
      Tone3();                   //
    while (PINB5_bit) ;          // Wait for button to be released

    if (PINB4_bit)               // If PORTB.4 is pressed play Melody2
      Melody2();                 //
    while (PINB4_bit) ;          // Wait for button to be released

    if (PINB3_bit)               // If PORTB.3 is pressed play Melody
      Melody();                  //
    while (PINB3_bit) ;          // Wait for button to be released
  }
}

HW Connection

Example of Sound Library connection

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