Das Infolexikon

#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdio.h>
#include <stdint.h>
#include <avr/pgmspace.h>
#include <util/delay.h>
#include "lcd-routines.h"

// Noten-Frequenzen,
// berechnet für 8Mhz und PWM ohne Prescaler
#define c 542
#define cis 574
#define d 608
#define dis 644
#define e 682
#define f 722
#define fis 765
#define g 810
#define gis 858
#define a 908
#define b 962
#define h 1019

#define p 0   // Pause

struct notendauer
{
uint16_t note;
uint16_t dauer;
};

struct notendauer entchen[28] =
{
{c,1200},{d,1200},{e,1200},{f,1200},{g,1600},
{g,1600},{a,800},{a,800},{a,800},{a,800},
{g,1600},{a,800},{a,800},{a,800},{a,800},
{g,1600},{f,1200},{f,1200},{f,1200},
{f,1200},{e,1200},{e,1600},{d,1200},
{d,1200},{d,1200},{d,1200},{c,1600},
{p,60000}
};

// einfache Sinuswelle in 256 diskreten Werten
const uint8_t  sinewave[1][256] PROGMEM=
{
{
0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,
0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,
0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf5,
0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,
0xf6,0xf5,0xf3,0xf2,0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe2,0xe0,0xde,0xdc,
0xda,0xd8,0xd5,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,0xbc,0xb9,0xb6,0xb3,
0xb0,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x98,0x95,0x92,0x8f,0x8c,0x89,0x86,0x83,
0x80,0x7c,0x79,0x76,0x73,0x70,0x6d,0x6a,0x67,0x63,0x60,0x5d,0x5a,0x57,0x54,0x51,
0x4f,0x4c,0x49,0x46,0x43,0x40,0x3e,0x3b,0x38,0x36,0x33,0x31,0x2e,0x2c,0x2a,0x27,
0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,0x15,0x13,0x12,0x10,0x0f,0x0d,0x0c,0x0a,
0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x03,0x02,0x01,0x01,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x05,0x06,0x07,0x08,
0x09,0x0a,0x0c,0x0d,0x0f,0x10,0x12,0x13,0x15,0x17,0x19,0x1b,0x1d,0x1f,0x21,0x23,
0x25,0x27,0x2a,0x2c,0x2e,0x31,0x33,0x36,0x38,0x3b,0x3e,0x40,0x43,0x46,0x49,0x4c,
0x4f,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,0x67,0x6a,0x6d,0x70,0x73,0x76,0x79,0x7c
}
};

uint16_t i=0;
uint8_t tone=0;
volatile uint16_t scale=523;

// Interrupt-Funktion, die den "Zeiger" hochzählt
// je nach gewünschter Frequenz wird "scale" verändert, 
// und somit die Sinuswelle schneller (hoher ton) 
// oder langsamer (tiefer Ton) abgelaufen
ISR(TIMER1_COMPA_vect){
	OCR1A=pgm_read_byte(&sinewave[tone][(i>>8)]);
   	i += scale;
}


int main(void)
{
    // PWM-INIT -----------------------------------
	// Alle B-Pins als Ausgänge
	DDRB=0xFF;
	
	// Anfangswert der PWM
	OCR1A=0x80;
	
	//Output compare OC1A 8 bit non inverted PWM
	// Timer Counter Control Register!
	// Bit:   7	  6	 5	4     3     2     1     0
	// Bed: COM1A1 COM1A0 COM1B1 COM1B0 FOC1A FOC1B WGM11 WGM10
	// Hier:  1       0      0      1     0     0     0     1
	TCCR1A=0x91;
	
	// Timer ohne Prescaler starten
	TCCR1B=0x01;
	
	// Einschalten des Ausgangs-Vergleichs-Interrupts auf OCR1A (PB1)
	// Timer/Counter Interrupt Mask!
	// Bit:   7	6      5      4     3      2     1      0
	// Bed: OCIE2 TOIE2 TICIE1 OCIE1A OCIE1B TOIE1 ------ TOIE0	
	// Hier:  0	0      0      1     0      0     0      0
	TIMSK=0x10;
	//enable global interrupts
	sei();

    // MAIN-LOOP ----------------------------------
    while(1)
    {
	// durch das Noten-Array laufen und nacheinander
	// die Töne in jeweiliger Länge abspielen
	// da "scale" global definiert ist, kann es einfach
	// hier geändert werden!
	for(int y=0;y<26;y++){
		scale = entchen[y].note;
		_delay_ms(entchen[y].dauer);

		// Interrupt kurz ausschalten, gibt kurze Pause
		// so werden die Töne getrennt
		cli();
		_delay_ms(400);
		i=0;
		sei();

	}

    }//while(1)
    return 0;
}