ATmega328p ADC snippet

adcm328.c

#include <avr/io.h>
#include <inttypes.h>
#include "adc.h"

void adcenable( )
{
	//Enable ADC
	ADCSRA = ( 1 << ADEN );
}

void adcdisable( )
{
	//Disable ADC
	ADCSRA &= ~( 1 << ADEN );
}

uint16_t adcread( uint8_t mux )
{
	//Read data from selected ADC (VCC as reference volatge)
	ADMUX = ( mux << MUX0 ) | ( 1 << REFS0 );
	ADCSRA |= ( 1 << ADSC );
	while ( ADCSRA & ( 1 << ADSC ) );
	return ADC;
}

adcm328.h

#ifndef ADC_H
#define ADC_H

#include <avr/io.h>
#include <inttypes.h>

extern void adcenable( );
extern void adcdisable( );
extern uint16_t adcread( uint8_t mux );

#endif