/******************************************************************************************
*
*	Function name : ADC_conversion
*
*	Returns :	unsigned int adc result, 8 x averaged
*
*	Parameters :	None
*
*	Purpose :	Run the ADC conversion on ATMEGA16
*
******************************************************************************************/

unsigned int ADC_conversion(unsigned char source)  // needs approx 9*250µs = 2.25ms
{
    unsigned char i;
    unsigned int ADC_temp  = 0;
    unsigned int adcresult = 0;
    
	
     ADMUX = source;     // select ax, ay or bat_mon, each single ended
        
     delay(66);          // some delay for channel selection to settle!
			 // ADC needs 13 cyles/conversion = 13*16,1µs = 209µs 

	ADCSRA |= (1<<ADSC);    // do a single dummy conversion -> batmon() conflict solution
    while(!(ADCSRA & 0x10));    // wait for conversion done, ADIF flag active						 
    
    for(i=0;i<8;i++)            // do the ADC conversion 8 times for better accuracy 
    {
        ADCSRA |= (1<<ADSC);        // do single conversion
        while(!(ADCSRA & 0x10));    // wait for conversion done, ADIF flag active

		ADC_temp = ADC;	    // read ADC register (16 bit)
		
        adcresult += ADC_temp;      // accumulate result (8 samples) for later averaging
    }
    
    adcresult = adcresult >> 3;     // average the 8 samples
	
	return adcresult;
}