#include <avr/io.h>
#include <util/delay.h>
#include <stdint.h>

#define output(directions,pin) (directions |= pin) // set port direction for output
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define bit_delay_time 100 // bit delay for 9600 with overhead
#define bit_delay() _delay_us(bit_delay_time) // RS232 bit delay
#define half_bit_delay() _delay_us(bit_delay_time/2) // RS232 half bit delay
#define char_delay() _delay_ms(10) // char delay

#define serial_port PORTB
#define serial_direction DDRB
#define serial_pin_out (1 << PB2)

#define TRUE 1
#define FALSE 0

static char lo_byte;
static char hi_byte;

void put_char(volatile unsigned char *port, unsigned char pin, char txchar) {
   //
   // send character in txchar on port pin
   //    assumes line driver (inverts bits)
   //
   // start bit
   //
   clear(*port,pin);
   bit_delay();
   //
   // unrolled loop to write data bits
   //
   if bit_test(txchar,0)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,1)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,2)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,3)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,4)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,5)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,6)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,7)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   //
   // stop bit
   //
   set(*port,pin);
   bit_delay();
   //
   // char delay
   //
   bit_delay();
}

uint16_t getIntValue(){
	uint16_t hi = hi_byte;
	uint16_t lo = lo_byte;
	hi = hi * 256;
	hi += lo;
	return hi;
}

void setADC1(){
	   ADMUX = (0 << REFS1) | (0 << REFS0) // Vcc ref
	      | (0 << MUX5) | (0 << MUX4) | (0 << MUX3) | (1 << MUX2) | (1 << MUX1) | (1 << MUX0); // ADC7
}

void setADC2(){
	   ADMUX = (0 << REFS1) | (0 << REFS0) // Vcc ref
	      | (0 << MUX5) | (0 << MUX4) | (0 << MUX3) | (0 << MUX2) | (1 << MUX1) | (1 << MUX0); // ADC3
}

void setADC3(){
	   ADMUX = (0 << REFS1) | (0 << REFS0) // Vcc ref
	      | (0 << MUX5) | (0 << MUX4) | (0 << MUX3) | (0 << MUX2) | (1 << MUX1) | (0 << MUX0); // ADC2
}

void read1(){
	setADC1();
    //
    // initiate conversion
    //
    ADCSRA |= (1 << ADSC);
    //
    // wait for completion
    //
    while (ADCSRA & (1 << ADSC))
       ;

    lo_byte = ADCL;
    hi_byte = ADCH;
}

void read2(){
	setADC2();
    //
    // initiate conversion
    //
    ADCSRA |= (1 << ADSC);
    //
    // wait for completion
    //
    while (ADCSRA & (1 << ADSC))
       ;

    lo_byte = ADCL;
    hi_byte = ADCH;
}

void read3(){
	setADC3();
    //
    // initiate conversion
    //
    ADCSRA |= (1 << ADSC);
    //
    // wait for completion
    //
    while (ADCSRA & (1 << ADSC))
       ;

    lo_byte = ADCL;
    hi_byte = ADCH;
}

void turnLED1On(){
	  //LED is PB0
	  DDRA |= _BV(PB0); //Enable output on the LED pin
	  PORTA |= _BV(PB0); //turn LED on
}

void turnLED2On(){
	  //LED is PB1
	  DDRA |= _BV(PB1); //Enable output on the LED pin
	  PORTA |= _BV(PB1); //turn LED on
}

void turnLED3On(){
	  //LED is PB2
	  DDRA |= _BV(PB2); //Enable output on the LED pin
	  PORTA |= _BV(PB2); //turn LED on
}

void turnLED1Off(){
	  //LED is PB0
	  DDRA |= ~_BV(PB0); //Enable output on the LED pin
	  PORTA &= ~_BV(PB0); //turn LED off
}
void turnLED2Off(){
	  //LED is PB1
	  DDRA |= ~_BV(PB1); //Enable output on the LED pin
	  PORTA &= ~_BV(PB1); //turn LED off
}
void turnLED3Off(){
	  //LED is PB2
	  DDRA |= ~_BV(PB2); //Enable output on the LED pin
	  PORTA &= ~_BV(PB2); //turn LED off
}

void sendChar(char c){
    put_char(&serial_port, serial_pin_out, c);
    char_delay();
}

void sendBytes(){
	sendChar(hi_byte);
	sendChar(lo_byte);
}

int main(void) {
   //
   // main
   //
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize output pins
   //
   set(serial_port, serial_pin_out);
   output(serial_direction, serial_pin_out);
   //
   // init A/D
   //
   ADCSRA = (1 << ADEN) // enable
      | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); // prescaler /128
   //
   // main loop
   //
   while (1) {
      //
      // send framing
      //
	   sendChar(1);
	   sendChar(2);
	   sendChar(3);
	   sendChar(4);

	   read1();
	   sendBytes();

	   uint16_t val = getIntValue();
	   /*
	    * int16_t  int8_t int32_t
	    */

	   read2();
	   sendBytes();

	   val = getIntValue();
	   /*
	   * int16_t  int8_t int32_t
	   */

	   read3();
	   sendBytes();

	   val = getIntValue();
	   /*
	   * int16_t  int8_t int32_t
	   */

      }
   }