#include <avr/io.h>		// for the input/output register

  #include <util/delay.h>

  
  // For the serial port
  

  #define CPU_FREQ	16000000L   // Assume a CPU frequency of 16Mhz
  #define tempo	25
  #define debit	9600		//débit liaison série en bauds
  #define ADC0	0
  #define ADC1	1

  #define debut_serial_tx	0x40		//pour détecter la transmission d'une trame pour le 16u2

  
  void init_serial(int speed)
  {
  /* Set baud rate */
  UBRR0 = CPU_FREQ/(((unsigned long int)speed)<<4)-1;
  
  /* Enable transmitter & receiver */
  UCSR0B = (1<<TXEN0 | 1<<RXEN0);
  
  /* Set 8 bits character and 1 stop bit */
  UCSR0C = (1<<UCSZ01 | 1<<UCSZ00);
  
  /* Set off UART baud doubler */
  UCSR0A &= ~(1 << U2X0);
  }
  
  void send_serial(unsigned char c)
  {

  	loop_until_bit_is_set(UCSR0A, UDRE0);
  	UDR0 = c;

  }
  
  unsigned char get_serial(void) {

  	loop_until_bit_is_set(UCSR0A, RXC0);
  	return UDR0;

  }
  
  // For the AD converter
  
  void ad_init(unsigned char channel)   
  {   

  	ADCSRA|=(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);   
  	ADMUX|=(1<<REFS0)|(1<<ADLAR);
  	ADMUX=(ADMUX&0xf0)|channel;   
  	ADCSRA|=(1<<ADEN);

  }   
  
  //récupère la valeur de l'ADCH
  unsigned int ad_sample(void){

  	ADCSRA|=(1<<ADSC);
  	while(bit_is_set(ADCSRA, ADSC));
  	return ADCH;

  }
  
  // For the I/O 
  void output_init(void){

  	DDRB |= 0b00111111; // PIN 8-13 as output (LED)

  }
  

  /*

  void output_set(unsigned char value){

  	if(value==0) PORTB &= 0xfe; else PORTB |= 0x01;

  }

  */

  
  void input_init(void){

  	DDRD &= 0b10000011;	// PIN 2-6 as input (Bouton Joystick + boutons)
  	PORTD |= 0x7C; // Pull up de 0 à 1

  }
  

  /*

  unsigned char input_get(void){

  	return ((PIND&0x04)!=0)?1:0;

  }

  */

  /* Commande des LED */

  void commande_leds(){
  	unsigned char temp_serial, leds;

  	temp_serial = UDR0;
  	if (temp_serial !=0){
  		leds = temp_serial;
  		// Allumer LED de 'A' à 'F'

  		if (leds == 'A') PORTB = PORTB | 0x01; 
  		if (leds == 'B') PORTB = PORTB | 0x02;
  		if (leds == 'C') PORTB = PORTB | 0x04;
  		if (leds == 'D') PORTB = PORTB | 0x08;
  		if (leds == 'E') PORTB = PORTB | 0x10;
  		if (leds == 'F') PORTB = PORTB | 0x20;

  		
  		// Eteindre LED de 'a' à 'f'

  		if (leds == 'a') PORTB = PORTB & 0xfe;
  		if (leds == 'b') PORTB = PORTB & 0xfd;
  		if (leds == 'c') PORTB = PORTB & 0xfb;
  		if (leds == 'd') PORTB = PORTB & 0xf7;
  		if (leds == 'e') PORTB = PORTB & 0xef;
  		if (leds == 'f') PORTB = PORTB & 0xdf;

  	}

  }
  

  /* Récupération de la valeur des boutons et mise en forme */

  unsigned char get_buttons(void){

  	unsigned char boutons = PIND;
  	boutons = boutons >>2;
  	boutons = boutons & 0b00111111;
  	boutons = boutons | 0b00100000;
  	
  	return boutons;

  }

  /* Met en forme l'octet de l'axe pos du joystick */

  unsigned char shape_joy(unsigned char pos){

  	pos = pos >>3;	//On récupère les 5 bits de poids forts de l'ADCH (diminuer sensibilité)

  	pos = pos & 0b00111111;
  	pos = pos | 0b00100000;
  	return pos;

  }

  /* Récupération de la valeur de l'axe du joystick sur la chaîne channel du CAN */

  unsigned char get_joystick(int channel){

  	unsigned char axis;
  	ad_init(channel);
  	axis = ad_sample();
  	axis = shape_joy(axis);
  	return axis;

  }
  
  /* Dummy main */
  int main(void){

  
  	//INITIALISATIONS  

  	unsigned char boutons, boutons_anc;
  	unsigned char joystick_x=0x10, joystick_x_anc=0x10;
  	unsigned char joystick_y=0x10, joystick_y_anc=0x10;

  	init_serial(debit);
  	output_init();
  	input_init();

  
  	//Récupération des valeurs des boutons et joystick, et mise en forme

  	boutons = get_buttons();

  	joystick_x = get_joystick(ADC0);
  	joystick_y = get_joystick(ADC1);

  	while(1){

  		boutons_anc = boutons;
  		joystick_x_anc = joystick_x;
  		joystick_y_anc = joystick_y;

  		//Récupération des valeurs des boutons et joystick, et mise en forme
  		boutons = get_buttons();

  		joystick_x = get_joystick(ADC0);

  		_delay_ms(tempo);

  		joystick_y = get_joystick(ADC1);

  		//Port série libre
  		if ((UCSR0A & (1<<RXC0)) == 0){
  			// Si une des grandeurs a changé
  			if ((boutons_anc != boutons) || (joystick_x_anc != joystick_x) || (joystick_y_anc != joystick_y)){
  				/* On envoie la trame des grandeurs */
  				send_serial(debut_serial_tx);	//début de trame
  				send_serial(boutons);			//état global des grandeurs
  				send_serial(joystick_x);
  				send_serial(joystick_y);    	  	
  				//retour chariot
  				send_serial(0x0a);
  				send_serial(0x0d);

  			}

  		}
  		
  		//Port série occupé	

  		else{

  			commande_leds();	//On gère la commande des leds

  		}

  	}  

  	return 0;

  }