UniversalModuleDrivers/adc.c at master · FuelFighter/UniversalModuleDrivers · GitHub

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/*
 * adc.c
 *
 * Created: 18.02.2017 10:41:35
 *  Author: olesot
 */

//Written for UM

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

void adc_init(void){

	/* Voltage ref AVcc with external capacitor on AREF pin */
	ADMUX |= (1<<REFS0);

	/* Select prescaler to 64 --> conversion f= 125kHz */
	ADCSRA |= (1<<ADPS2)|(1<<ADPS2);

	/* Enable the ADC */
	ADCSRA |= (1<<ADEN);
}

uint16_t adc_read(adc_channel_t channel){

	//Setting channel and type of reading, see enum in adc.h
	ADMUX &= 0b11100000;
	ADMUX |= (int8_t)channel;

	/* Start the conversion */
	ADCSRA |= (1<<ADSC);

	/* Wait for the conversion to complete */
	while(ADCSRA & (1<<ADSC));

	return ADC;
}

void adc_Free_running_init(void){

	/* Voltage ref AVcc with external capacitor on AREF pin */
	ADMUX |= (1<<REFS0);

	/* Select prescaler to 64 --> conversion f= 125kHz */
	ADCSRA |= (1<<ADPS2);

	/* Auto trigger of ADC */
	ADCSRA |= (1<<ADATE);

	/* Enable Interrupt of ADC */
	ADCSRA |= (1<<ADIE);

	/* Free running mode */
	ADCSRB &= ~((1<<ADTS2)|(1<<ADTS1)|(1<<ADTS0)); // (initially at 0 so not useful)

	/* Enable the ADC */
	ADCSRA |= (1<<ADEN);

	/* Start the conversion */
	ADCSRA |= (1<<ADSC);
}

uint16_t adc_Free_running_read(adc_channel_t channel){
	//Setting channel and type of reading, see enum in adc.h
	ADMUX &= 0b11100000;
	ADMUX |= (int8_t)channel;

	return (ADCL+(ADCH<<8));
}

void Set_ADC_Channel(adc_channel_t channel)
{
	channel &= 0b00000111;  // AND operation with 7
	ADMUX = (ADMUX & 0xF8)|channel; // clears the bottom 3 bits before ORing
}