void EnableADCInt(uint8_t channel)
{
    // Clear PRADC to startup ADC
    PRR &= ~(1<<PRADC);  // Power Reduction Register
  
    ADMUX = 0;
	ADMUX |= (1 << REFS1)  |  (1 << REFS0);   
	ADMUX |=   channel;
	ADCSRA =  ( 1 << ADPS2)  |  ( 0 << ADPS1) | ( 1 << ADPS0) ;

	// Für Interrupt bei Free Running ?
	// ADCSRA |= ( 1 << ADATE);
	
	// Free running mode !?
	// ADCSRB = 0;

	// sleep Mode
	set_sleep_mode(SLEEP_MODE_ADC);
	
	// Bit 3 – ADIE: ADC Interrupt Enable
	// Bit 7 – ADEN: ADC Enable    
	// Bit 6 – ADSC: ADC Start Conversion   but not for noise reduction ?
	ADCSRA |= (1 << ADEN)  |  (1 << ADIE);

	// enable Global Int
	sei();
}

void DisableADCInt()
{
	// disable ADC Int
	// Bit 3 – ADIE: ADC Interrupt Disable
	// Bit 7 – ADEN: ADC Disable
	// Bit 6 – ADSC: ADC Stop Conversion  
	ADCSRA = 0;
	
	PRR |= (1<<PRADC);
}

int16_t GetADCTemp(uint8_t channel)
{
	EnableADCInt(channel);  
	
	sleep_cpu();  // Ersten Wert verwerfen

	adcCount=0;
	adcValue=0;
	while( adcCount < 64 )
	{
        adcCount++;
		sleep_cpu();
	}
		
	DisableADCInt();

    int16_t  ticksresult = (adcValue >> 6);

    return ticksresult;  
}

ISR(ADC_vect)
{
	adcValue =  ADC;   // low + high byte
}