#include <avr/io.h>
#include <stdio.h>
#include <avr/signal.h>
#include <avr/interrupt.h>


 
 #define TCNT0_START 253
 #define TCNT0_START2 0xB8

 #define PC0_EIN (PORTC &=~(1<<PC0))
 #define PC0_AUS (PORTC |= (1<<PC0)) 



 #define FREQUENZ_2 (PINC & (1<<PC2))
 #define PA0_EIN (PORTA &=~(1<<PA0))
 #define PA0_AUS (PORTA |= (1<<PA0))

 #define PA1_EIN (PORTA &=~(1<<PA1))
 #define PA1_AUS (PORTA |= (1<<PA1))

 #define PA2_EIN (PORTA ^=(1<<PA2))
 #define PA2_AUS (PORTA |= (1<<PA2))

 #define PA3_EIN (PORTA ^= (1<<PA3))
 #define PA3_AUS (PORTA |= (1<<PA3))

 void delay10us(unsigned int work)
 {	
 			while(work--)
			{
				TCNT0 = TCNT0_START2;				//Counter vorsetzen
				TCCR0 |= (1<<CS02);    				//Teiler 256 und START
				while(!(TIFR & (1<<TOV0)));			//warten auf Überlauf, Polling
				TIFR |= (1<<TOV0); 				//Flag rücksetzen
				TCCR0 &=~(1<<CS02);				//Counter stoppen
 			}
 }


SIGNAL (SIG_INTERRUPT0)								//Nulldurchgang
 {
	
	PA2_EIN; PA3_EIN;							//Relais einschalten					
	delay10us(500);								//5ms verzögern, wegen halberperiodendauer 
										//und halbe helligkeit	
	PA2_AUS; PA3_AUS;							//Relais ausschalten


 }	


 int main (void)
 {
	DDRA = 0x0F;							
	PORTA=0xFF;

	

	MCUCR |= (1<<ISC01);
	GICR |= (1<<INT0);

	sei();

 	
	while(1);
	

}