#include <stdio.h>
#include <stdint.h>
#include <ctype.h>
#include <avr/io.h>         // include I/O definitions (port names, pin names, etc)
#include <avr/interrupt.h>  // include interrupt support
#define USART_BAUDRATE 9600
#define F_CPU 8000000
#define MYUBRR F_CPU/16/USART_BAUDRATE-1
static volatile unsigned char temp; //so it is global, because we can not return from interrupt

int printCHAR(char character, FILE *stream)
{
   while ((UCSR0A & (1 << UDRE)) == 0) {};

   UDR0 = character;

   return 0;
}

FILE uart_str = FDEV_SETUP_STREAM(printCHAR, NULL, _FDEV_SETUP_RW);


void adc_init(void) // Function to initialise the ADC feature
{
    ADCSRA=0X00; // Clear previous ADC results and status flags
    ADMUX |= (1 << ADLAR) | (1 << REFS0);
    ADCSRA |= (1 << ADSC) | (1 << ADEN) | (1 << ADPS1) | (1 << ADPS2)|(1<<ADIE); //interrpts now enabled
}




/*unsigned char adc_start(unsigned char channel) // Function to perform an ADC conversion, Takes 0-8 as input
// to select which input to convert
{
    unsigned char i;
    ADCH=0x00; // Clear the previous result

    i=channel&0x07; // Decide which line to perform ADC conversion on
    ADMUX=i|0x60; // Enter which line to perform in the ADC control register
    ADCSRA|=1<<ADSC;

    while(ADCSRA & (1<<ADSC));  // wait for conv. to complete
    unsigned char temp=ADCH; //unsigned int temp=ADC;   for 10 bits
    return temp;
}
*/
ISR(ADC_vect){
// NOT USING ADC CHANNEL SELECTOR FOR NOW
//
//
//      unsigned char i;
//  ADCH=0x00; // Clear the previous result
//  i=channel&0x07; // Decide which line to perform ADC conversion on
//  ADMUX=i|0x60; // Enter which line to perform in the ADC control register
 // wait for conv. to complete
    temp = ADCH; //unsigned int temp=ADC;   for 10 bits
    printf("read: %d \n\r", temp);
    ADCSRA|=1<<ADSC;
}

int main (void)
{

   UCSR0B |= (1 << RXEN) | (1 << TXEN);   // Turn on the transmission and reception circuitry
   UCSR0C |= (1 << UCSZ0) | (1 << UCSZ1); // Use 8-bit character sizes
   UBRR0H = (MYUBRR >> 8); // Load upper 8-bits of the baud rate value into the high byte of the UBRR register
   UBRR0L = MYUBRR; // Load lower 8-bits of the baud rate value into the low byte of the UBRR register
   stdout = &uart_str;
   printf("Hello World\n\r");
   uint8_t result=0;
   adc_init();
   sei();//global interrupts enable

   while(1){
   }


}