/*
 * readAdc.c
 * This program reads from ADC0 (A0) and sends the result through serial to the PC
 *
 * Created: 4/14/2015 10:43:45 PM
 */ 

#define F_CPU 16000000UL
#include "util/delay.h"

#include <avr/io.h>
#include "string.h"
#include "stdio.h"


void usart_init (void);
void usart_send (char ch);
void usart_sendString(char str[]);

unsigned int adc_read(unsigned char channel);

int main(void)
{
	char str[7];
	usart_init();

	while(1)
	{
		sprintf(str,"%d\r", adc_read(0));
		usart_sendString(str);
		_delay_ms(100);
	}
	
	return 0;
}

//******************************************
//  initializes UART0 for sending data
//  baud rate = 9600, stop bit = 1, parity = No parity
//******************************************
void usart_init (void)
{
	UCSR0B = (1<<TXEN0) ;
	UCSR0C = (1<< UCSZ01)|(1<<UCSZ00);
	UBRR0L = ((F_CPU/16)/9600) - 1;
}

//******************************************
//  sends a byte of data through serial
//
//  Parameters:
//    ch : the character to be sent
//******************************************
void usart_send (char ch)
{
	while (! (UCSR0A & (1<<UDRE0)));

	UDR0 = ch ;
}

//******************************************
//  sends a zero-ended string through serial
//
//  Parameters:
//    str : the string to be sent
//******************************************
void usart_sendString(char str[])
{
	unsigned char i = 0;

	while(str[i] != 0)
	{
		usart_send(str[i]);
		i++;
	}
}

//******************************************
//  reads an ADC
//
//  Parameters:
//    channel : the ADC channel to be read
//  Returns:
//    the ADC value
//******************************************
unsigned int adc_read(unsigned char channel)
{
  	ADCSRA = 0x87;
  	ADMUX = 0xC0|channel;
  	
  	ADCSRA|=(1<<ADSC);

	while((ADCSRA&(1<<ADIF))==0);

	return ADC;
}