int readADC(int channel)
{
int val=0;
ADCSRA |= (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0) | (1 << ADIF);; // Set ADC prescalar to 128 - 125KHz sample rate @ 16MHz
ADMUX = channel;
ADMUX |= (1 << REFS0); // Set ADC reference to AVCC
ADMUX |= (1 << ADLAR); // Left adjust ADC result to allow easy 8 bit readin
...