uart in .c und .h File auslagern

static int8_t uart_getchar(FILE *STREAM)

{

  while (!(UCSR0A & (1 << RXC0)));

  return (UDR0);

}

//Empfaengt 1 Byte vom UART

static int8_t uart_getchar(FILE);

/* main.c */

//#include <string.h>

//#include <stdlib.h>

//#include <stdio.h>

//#include <ctype.h>

#include <avr/io.h>

//Initialisierung und die Funktionen uart_putchar und art_getchar

#include "uart.h"

//Eintrag von uart_putchar und uart_getchar als 

//Standard IO

FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, uart_getchar, _FDEV_SETUP_RW);

int main(void)

{ 

  //Initialisierung (aus serial2.h) aufrufen 

  uart_init(F_CPU, BAUD);        

  //Elementare IO Funktionen als Standard IO eintragen

  stdout = stdin = &mystdout;  

  printf("\r\nHello World!");

  while (1)

  {

  // ...

  }

}

/* uart.h */

#define F_CPU 16000000UL

#define BAUD  11000

//#include <string.h>

//#include <stdlib.h>

#include <stdio.h>  // FILE

//#include <ctype.h>

#include <avr/io.h>

//Initialisiert UART gegebener Oszillatorfrequenz und Baudrate

void uart_init(uint32_t, uint32_t);

//Sendet 1 Byte an UART

int8_t uart_putchar(char, FILE*);

//Empfaengt 1 Byte vom UART

static int8_t uart_getchar(FILE);

/* uart.c */

#include "uart.h"

void uart_init(uint32_t Oszi, uint32_t Baud)

{

  if ((Oszi / 16L / Baud - 1) > 30)

  {

    UBRR0L = (unsigned char)(Oszi /16L / Baud - 1);

    UBRR0H = (unsigned char)((Oszi / 16L / Baud - 1) >> 8);

    UCSR0A = 0;

  }

  else

  {

    //Falls Teilerwert zu klein => Rundungsfehler

    //Daher doppelte Rate waehlen

    UBRR0L = (unsigned char)(Oszi / 8L / Baud - 1);

    UBRR0H = (unsigned char)((Oszi / 8L / Baud - 1) >> 8);

    UCSR0A = (1 << U2X0);

  }

  UCSR0B = UCSR0B | (1 << TXEN0) | (1 << RXEN0);

  UCSR0C = UCSR0C | (1 << UMSEL01) | (1 << UCSZ01) |

  (1 << UCSZ00);

}

//Sendet 1 Byte an UART

int8_t uart_putchar(char data, FILE* stream)

{

  while (!(UCSR0A & (1 << UDRE0)));

  UDR0 = (char)data;

  return 0;

}

//Empfaengt 1 Byte vom UART

static int8_t uart_getchar(FILE *STREAM)

{

  while (!(UCSR0A & (1 << RXC0)));

  return (UDR0);

}