#include "serial.h"
  
  void init_serial(unsigned long int speed) //initialisation de la liaison série
  {
  /* 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(uint8_t c) //envoyer un carctère sur le port série
  {
  loop_until_bit_is_set(UCSR0A, UDRE0);
  UDR0 = c;
  }
  
  
  uint8_t get_serial(void) //récupérer un caractère envoyé sur le port série
  {
  loop_until_bit_is_set(UCSR0A, RXC0);
  return UDR0;
  }
  
  void send_ack(void){
    send_serial(0x01);
  }