ab jetzt mal einfach alle Bit-Warteschleifen gegen delay warteschleifen
getauscht.

char TWI_empf(unsigned char adres)
{

TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
//loop_until_bit_is_set(TWCR, TWINT);
_delay_ms(100);
TWDR = adres;
TWCR = (1<<TWINT)|(1<<TWEN);
//loop_until_bit_is_set(TWCR, TWINT);
_delay_ms(100);
TWCR = (1<<TWINT)|(1<<TWEN);
//loop_until_bit_is_set(TWCR, TWINT);
_delay_ms(100);
dat1 = TWDR ;
TWCR = (1<<TWINT)|(1<<TWEA)|(1<<TWEN);

TWCR = (1<<TWINT)|(1<<TWEN);
//loop_until_bit_is_set(TWCR, TWINT);
_delay_ms(100);
dat2 = TWDR ;

//loop_until_bit_is_set(TWCR, TWINT);
_delay_ms(100);
TWCR = (1<<TWINT)|(1<<TWSTO)|(1<<TWEN);

return dat1;
}