// Using a buzzer (beeper) USMT-9043A (DELTRON)
// Buzzer resonance freq. is 2,7kHz
// Routines for ATMEGA16 @ 4MHz, Port B, Pin1
// Last modified: 04-MAY-06
// D. Kleine-Beck

/* Includes */
#include "iom16v.h"
#include "gmeter_II.h"

#define BUZZER		  	(1 << 1)
#define buzzer_on()	  	(PORTB &= ~BUZZER)
#define buzzer_off()  		(PORTB |= BUZZER)   



// -------- TONES ---------

// user defined beep 
// in: Frequency in 1-10 kHz and duration in ms
void buzzer_beep (unsigned char freq, unsigned int duration)  //
 {
   unsigned int ticks, i;	 	   // 0,0015ms/delay(x)
 
  
   ticks = ((int)((100/freq)/2)*6); // not exactly (+5% in freq...) max=300
  
  // duration: 667*ticks from delay(ticks) per ms // max 5s@10kHz, 50s@1kHz
  
   i = ((long)duration*334)/ticks;  // 
  
   while (i--)  			// 1000*0,5ms = 0,5s
   {
     delay(ticks);  	  	// approx 0.25ms delay
     buzzer_on();
     delay(ticks);
     buzzer_off();
   }
 }



//-----------------------------


// multi purpose delay - main loop = 6clocks
 void delay(int ticks)
  {
    while(ticks--);
  }