// Happy Birthday Card by Drew Fustini:

// http://us.element14.com/fustini

// Modified from musicbox1.c by NerdKits:

// http://www.nerdkits.com/videos/musicbox1/

#define F_CPU 9600000UL //9.6MHz

#include <avr/io.h>

#include <avr/sleep.h>

// Frequencies from http://www.phy.mtu.edu/~suits/notefreqs.html

// converted to half-periods (us) by calculating

// 1000000/2/frequency where frequency is in Hz

// note: additionally adjusted to compenstate for ATtiny13

#define D5 1050

#define E5 935

#define Fsh5 833

#define G5 786

#define A5 701

#define A4 1402

#define B5 624

#define C6 588

#define D6 524

//Note Durations

#define DUR2 110

#define DUR4 55

#define DUR8D 40

#define DUR16 13

#define nop() asm volatile("nop")

//Delay specified number of microseconds

//warning: 1 "microsecond" = 1.23 real microseconds

void delay_us(uint16_t delay) {

uint16_t i = 0;

for(i=0;i<delay;i++) {

nop();

}

}

//Plays specified frequency for a specified duration

void play_tone(uint16_t delay, uint8_t duration) {

// delay is half-period in microseconds

// duration is in 10ms increments

// duration = 2*delay * cycles (all in same units)

// cycles = 10000 * duration / delay / 2

// cycles = 100 * duration / (delay/50)

uint16_t tmp = 100 * duration;

uint16_t delaysm = delay / 50;

uint16_t cycles = tmp / delaysm;

while(cycles > 0) {

PORTB = 0xFF; //set speaker high (ideally could be more granular)

delay_us(delay);

PORTB = 0x00; //set speaker low

delay_us(delay);

cycles--;

}

delay_us(0xFFFF);

}

int main() {

delay_us(0xFFFF); //brief delay at startup

DDRB = 0xFF; //set pins to output, ideally should be more granular

//Play "Happy Birthday" one time

play_tone(D5, DUR8D);

play_tone(D5, DUR16);

play_tone(E5, DUR4);

play_tone(D5, DUR4);

play_tone(G5, DUR4);

play_tone(Fsh5, DUR2);

play_tone(D5, DUR8D);

play_tone(D5, DUR16);

play_tone(E5, DUR4);

play_tone(D5, DUR4);

play_tone(A5, DUR4);

play_tone(G5, DUR2);

play_tone(D5, DUR8D);

play_tone(D5, DUR16);

play_tone(D6, DUR4);

play_tone(B5, DUR4);

play_tone(G5, DUR4);

play_tone(Fsh5, DUR4);

play_tone(E5, DUR2);

play_tone(C6, DUR8D);

play_tone(C6, DUR16);

play_tone(B5, DUR4);

play_tone(G5, DUR4);

play_tone(A5, DUR4);

play_tone(G5, DUR2);

PORTB=0x00; //all pins GND

DDRB=0xFF; //all pin states Input

MCUCR = _BV(SM1) | _BV(SE); //configure sleep mode

sleep_cpu(); //sleep until button pressed again

return 0;

}