Create Musical Tone using PIC Code

The mikroC 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

Prototype	void Sound_Init(char *snd_port, char snd_pin);
Returns	Nothing.
Description	Configures the appropriate MCU pin for sound generation. Parameters : snd_port: sound output port address snd_pin: sound output pin
Requires	Nothing.
Example	// 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);

Code Example

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

 

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

void main() {

  ANSEL  = 0;                        // Configure AN pins as digital
  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);             // Play sound at 880Hz for 1 second

  while (1) {
    if (Button(&PORTB,7,1,1))        // RB7 plays Tone1
      Tone1();
    while (RB7_bit) ;                // Wait for button to be released

    if (Button(&PORTB,6,1,1))        // RB6 plays Tone2
      Tone2();
    while (RB6_bit) ;                // Wait for button to be released

    if (Button(&PORTB,5,1,1))        // RB5 plays Tone3
      Tone3();
    while (RB5_bit) ;                // Wait for button to be released

    if (Button(&PORTB,4,1,1))        // RB4 plays Melody2
      Melody2();
    while (RB4_bit) ;                // Wait for button to be released

    if (Button(&PORTB,3,1,1))        // RB3 plays Melody
      Melody();
    while (RB3_bit) ;                // Wait for button to be released
  }
}

HW Connection