Colony

/*

  buzzer.c - Contains the functions necessary for running the buzzer

  author: Robotics Club, Colony Project

  much taken from FWR's firefly library (author: Tom Lauwers)

*/

#include <avr/io.h>

#include <buzzer.h>

#include <time.h>

/**

 * @defgroup buzzer Buzzer

 * @brief Functions for controlling the buzzer.

 * Functions for controlling the buzzer. Include

 * buzzer.h to access these functions.

 * @{

 **/

/**

 * Initializes the buzzer. Must be called before any other buzzer

 * function may be used.

 **/

void buzzer_init( void )

{

        //NOTE: This is mostly handled by buzzer_Set_val for now

        // Set pin B7 to output - B7 is buzzer pin

        //DDRB |= _BV(DDB7);

        //Fast PWM Mode, Clear OCR0 on compare match and set at bottom, clock/64

        //TCCR2 = _BV(COM20) | _BV(WGM21)  | _BV(CS22);

}

/**

 * Sets the value of the buzzer's pitch.

 * Higher values are lower frequencies.

 *

 * @param buzz_value the value to set the buzzer's frequency too,

 * in the range 0-255

 *

 * @see buzzer_init, buzzer_set_freq, buzzer_off

 **/

void buzzer_set_val(unsigned int buzz_value)

{ 

        TCCR2 = _BV(COM20) | _BV(WGM21)  | _BV(CS22);

        DDRB |= _BV(DDB7);

        OCR2 = buzz_value;

}

/**

 * Sets the buzzer frequency. Usage of constants such as C4

 * is highly recommended as input to this function.

 * buzzer_init must be called before this function may

 * be used.

 *

 * @param buzz_freq the frequency to set the buzzer to

 *

 * @see buzzer_init, buzzer_set_val, buzzer_off

 **/

void buzzer_set_freq(unsigned int buzz_freq)

{

  int buzz_value;

  buzz_value = 62500/buzz_freq - 1;

  if(buzz_value > 255){

    buzz_value = 255;

  }else if(buzz_value < 0){

    buzz_value = 0;

  }

  buzzer_set_val(buzz_value);

}

/**

 * Plays the specified frequency for the specified

 * amount of time. This function blocks execution

 * until the time is completed. buzzer_init must be

 * called before this function can be used.

 *

 * @param ms the time in milliseconds to play the frequency

 * @param buzz_freq the frequency to play

 *

 * @see buzzer_init, buzzer_set_freq

 **/

void buzzer_chirp(unsigned int ms, unsigned int buzz_freq) 

{ 

  buzzer_set_freq(buzz_freq);

  delay_ms(ms);

  buzzer_off();

}

/**

 * Turns off the buzzer by disabling the timer0 clock.

 *

 * @see buzzer_init

 **/

void buzzer_off()

{

  // Disable clock, to halt counter

  TCCR2 &= 0xF8;//0b11111000;

  // Set buzzer pin low in case it's high

  PORTB &= 0xBF;//0b10111111;

}

/** @} **/ // end buzzer group