Kanalumschaltung ADC ATMEGA644

#define F_CPU 8000000UL

  #define Vref 4.94

  #include <avr/io.h>                  //einbinden der Bibliothek 'io.h'

  #include <util/delay.h>                //einbinden der Bibliothek 'delay.h'

  #include <avr/interrupt.h>

  #include <stdlib.h>

  #include "avr.h"

  #include "SPI.h"

  #include "UART.h"

  void ADC_init(void)

  {

    uint16_t first_result = 0;

    DIDR0 = (1<<ADC0D);

    ADMUX = (1<<REFS0); // | (1<<REFS1); //Einschalten der Referenzspannung: Vref = AVCC

    ADMUX |=(MUX0);

    ADCSRA = (1<<ADEN) | (1<<ADIE); // ADC aktivieren und Interrupt einschalten

    ADCSRA |= ((ADPS0) | (1<<ADPS1) | (1<<ADPS2)); //Prescaler 128

    _delay_ms(1);

    sei();

    ADCSRA |= (1<<ADSC);

    while (ADCSRA & (1<<ADSC))

    {

    }

    first_result = (ADCL + (ADCH<<8));

  }

  double calculate_adc(uint16_t value)

  {

    double result = 0.0;

    result = (value / 1024.0) * Vref;

    return result;

  }

  void start_converting(void)

  {

    ADCSRA |= (1<<ADSC);

    _delay_ms(1);

  }

  void select_adc(void)

  {

    int adc_number, adc_counter;

    if (!(PINC &(1<<PC0)))

    {

      adc_counter = 0;

      ADCSRA &= ~(1<<ADEN);

      ADMUX &= ~0x03; 

      ADMUX =(1<<MUX0);

      _delay_ms(1);

      ADCSRA |= (1<<ADEN);

      start_converting();

    }

    if (!(PINC &(1<<PC1)))

    {

      adc_counter = 1;

      ADCSRA &= ~(1<<ADEN);

      ADMUX &= ~0x03;

      ADMUX |=(1<<MUX1);

      _delay_ms(1);

      ADCSRA |= (1<<ADEN);

      start_converting();

    }

    if (adc_counter == 0)

    {

      adc_number = 0;

    }

    if (adc_counter == 1)

    {

      adc_number = 1;

    }

    if (adc_number == 0)

    {

      PORTD |=(1<<PD7);

      uart_putc(0x1b);

      uart_puts("[04;2H");

      Send_UART_Char("Aktiver ADC: ADC0");

    }

    if (adc_number == 1)

    {

      PORTD &= ~(1<<PD7);

      uart_putc(0x1b);

      uart_puts("[04;2H");

      Send_UART_Char("Aktiver ADC: ADC1");

    }

  }