#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <string.h>
#include <stdlib.h>

#define FOSC      16000000
#define baud_rate 9600
#define baud      FOSC/16/baud_rate-1

volatile unsigned int adc_val=0;
unsigned char adcval[10]={0};
unsigned char adctext[]="\nADC VAl: ";

void Transmit(unsigned char c)
{
  UDR0=c;
}

void adc_init()
{
    sei();
    DDRC=0x00;

    ADMUX  = ( (1<<REFS0) | (1<<REFS1) );
    ADCSRA = (  (1<<ADEN) | (1<<ADSC) | (1<<ADIE) |  (1<<ADIF) | (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0)); //Enable ADC, ADC Interrupt, Prescaler


}

void usart_init(unsigned int b_rate)
{
    UBRR0H=0x00;
    UBRR0L=0x00;
    UCSR0B=0x00;
    UCSR0C=0x00;
    UDR0  =0x00;

    UBRR0H  =(unsigned char)b_rate>>8;
    UBRR0L  =(unsigned char)b_rate;

    //Enable Rx, Tx, Enable Interrupt on UDR empty
    UCSR0B = ( (1<<RXEN0)  | (1<<TXEN0) | (1<<UDRIE0) );
    UCSR0C = ( (1<<UCSZ00) | (1 << UCSZ01) );
    sei();

}


int main (void)
{
  usart_init(baud);
  adc_init();

  while(1)
  {
     _delay_ms(1000);

  }

}

ISR(ADC_vect)
{

    adc_val= ADCL | (ADCH<<8);
    //strncat(adctext,itoa(adc_val, adcval,10),10 );
    ADCSRA = ( (1<<ADSC));
    itoa(adc_val,adcval,10);
}

ISR(USART_UDRE_vect)
{
    static int i=0;


    if(adcval[i++]!='\0')
      Transmit(adcval[i]);
    else
    {     i=0;
          Transmit('\n');
    }
}