Empf.c

#include <avr/io.h>

#include <avr/interrupt.h>

ISR(TWI_vect);

int main(void)

{

  uint8_t totzeit = 5;

  TCCR1A = 0xE0;    //PWM Phase/Freq correct

  TCCR1B = 0x11;    //"

  ICR1H = 0x00;    //TOP Value

  ICR1L = 0x80;    //TOP Value

  OCR1AH = 0x00;    //Compare High = 0

  OCR1BH = 0x00;    //"

  TWCR = (1<<TWEN)|(1<<TWEA)|(1<<TWIE);      // TWI enable, ack, Interrupt

  TWAR = 0x40;                  // Adresse, kein general Call

  TWSR = 0;

  DDRB = (1<<PB1)|(1<<PB2)|(1<<PB4);

  DDRD = (1<<PD6)|(1<<PD1)|(1<<PD0);

  ADMUX = (1<<REFS0)|(1<<REFS1)|(1<<MUX1)|(1<<MUX0)|(1<<ADLAR);  

    //int Referenz, ADC3, left adj.

  ADCSRA = (1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);  

    //enable, int, 128prescale

  SFIOR = 0x00;

  OCR1AL = 0x00;

  OCR1BL = 0xFF;

  PORTB = (1<<PB4);  // LED aus

  sei();

  while(1){};      // Endlosschleife Hauptprogramm

  return 0;

}

ISR(TWI_vect)

{

  PORTB &= ~(1<<PB4);   // LED an

  TWCR |= (1<<TWINT);    // 

}