RS485 Schaltung funktioniert nicht

ISR(USART0_RXC_vect)

{

  uint8_t dummy;

  dummy = UDR0;

  UART1_Transmit(dummy);

}

  DDRC = 0xFF;

  PORTC &= ~(1<<PC4);

PORTC &= ~(1<<PC5);

#define TR_DDR      DDRC

#define TR_PORT      PORTC

#define TR_PIN      3

int main(void)

{

  LED_DDR |= (1<<DDA0);

  LED_DDR |= (1<<DDA1);

  TR_DDR |= (1<<DDC3);

  TR_PORT |= (1<<TR_PIN);

  //Timer konfigurieren

  //stetige Wertanforderung

  TCCR1B |= (1<<CS12) | (1<<CS10); // standard = 9 Sekunden

  TCNT1 = 0; //29536; = 5 Sekunden

  LED_PORT |= (1<<LED1);

    //USART initialisieren

  //USART0

    UBRR0H = UBRR_VAL_ROTEL >> 8;

    UBRR0L = UBRR_VAL_ROTEL & 0xFF;

    //USART1

    UBRR1H = UBRR_VAL_KNX >> 8;

    UBRR1L = UBRR_VAL_KNX & 0xFF;

    //USART0

    UCSR0B |= (1<<TXEN0);                // UART TX einschalten

    UCSR0B |= (1<<RXEN0);

    UCSR0B |= (1<<RXCIE0);

    UCSR0C |= (1<<URSEL0)|(1<<UCSZ00)| (1<<UCSZ01);    // Asynchron 8N1

  //USART1

    UCSR1B |= (1<<TXEN1);                // UART TX einschalten

    UCSR1B |= (1<<RXEN1);

    UCSR1B |= (1<<RXCIE1);

    UCSR1C |= (1<<URSEL1)|(1<<UCSZ10)| (1<<UCSZ11);    // Asynchron 8N1

  USART_Transmit('A');

  UART1_Transmit('A');

  sei();          //activate Interrupts

    TIMSK |= (1<<TOIE1);

    while(1)

    {

      if(wert_anfordern == 1)    //Wertanforderung

      {

         TR_PORT |= (1<<TR_PIN);

        USART_Transmit('B');

        USART_Transmit('C');

        UART1_Transmit('K');

        wert_anfordern = 0;

         TR_PORT &= ~(1<<TR_PIN);

      }

    }

}

#ifndef F_CPU        //define F_CPU if not done

#define F_CPU 7372800UL

#endif

#include <avr/io.h>

#include <avr/interrupt.h>

#include <util/delay.h>

#include <stdlib.h>

#include <string.h>

//#include "lcd-routines.h"

/* 9600 baud  KNX */

#define BAUD1 9600UL          // Baudrate

#define UBRR_VAL_KNX ((F_CPU+BAUD1*8)/(BAUD1*16)-1)   // clever runden

/* 19200 baud Kessel */

#define BAUD2 1200UL          // Baudrate

#define UBRR_VAL_ROTEL ((F_CPU+BAUD2*8)/(BAUD2*16)-1)   // clever runden

#define LED_DDR         DDRA

#define LED_PORT        PORTA

#define TR_DDR      DDRC

#define TR_PORT      PORTC

#define TR_PIN      3

#define LED1            0

#define LED2            1

//#define TRANSMIT_ON    PORTC |= (1<<PC3)

//#define TRANSMIT_OFF  PORTC &= ~(1<<PC3)

//Statusdefinition

#define INIT      0

#define READY      1

//Variablen

volatile uint8_t PTX;      //Global Variable

char itoabuffer[20];

volatile uint8_t receive_string[20];

volatile uint8_t wert_anfordern = 0;

void USART_Transmit( char data )

{

  /* Wait for empty transmit buffer */

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

    ;

  /* Put data into buffer, sends the data */

  UDR0 = data;

}

void UART1_Transmit( char data )

{

  /* Wait for empty transmit buffer */

  while ( !( UCSR1A & (1<<UDRE1)) )

    ;

  /* Put data into buffer, sends the data */

  UDR1 = data;

}

ISR(USART0_RXC_vect)

{

  uint8_t dummy;

  dummy = UDR0;

  UART1_Transmit(dummy);

}

ISR(USART1_RXC_vect)

{

  uint8_t i = 0;

  uint8_t dummy;

      dummy = UDR1;

}

ISR(TIMER0_OVF_vect)

{

}

ISR(TIMER1_OVF_vect)

{

  wert_anfordern = 1;

  //receive_complete = 0;

}

int main(void)

{

  LED_DDR |= (1<<DDA0);

  LED_DDR |= (1<<DDA1);

  TR_DDR |= (1<<DDC3);

  TR_PORT |= (1<<TR_PIN);

  //Timer konfigurieren

  //stetige Wertanforderung

  TCCR1B |= (1<<CS12) | (1<<CS10); // standard = 9 Sekunden

  TCNT1 = 0; //29536; = 5 Sekunden

  //Timer für senden von Dimmtelegrammen ein Durchlauf ist 0,010s

  TCCR0 |= (1<<CS02) | (1<<CS00);

  TCNT0 = 184; //

  LED_PORT |= (1<<LED1);

    //USART initialisieren

  //USART0

    UBRR0H = UBRR_VAL_ROTEL >> 8;

    UBRR0L = UBRR_VAL_ROTEL & 0xFF;

    //USART1

    UBRR1H = UBRR_VAL_KNX >> 8;

    UBRR1L = UBRR_VAL_KNX & 0xFF;

    //USART0

    UCSR0B |= (1<<TXEN0);                // UART TX einschalten

    UCSR0B |= (1<<RXEN0);

    UCSR0B |= (1<<RXCIE0);

    UCSR0C |= (1<<URSEL0)|(1<<UCSZ00)| (1<<UCSZ01);    // Asynchron 8N1

  //USART1

    UCSR1B |= (1<<TXEN1);                // UART TX einschalten

    UCSR1B |= (1<<RXEN1);

    UCSR1B |= (1<<RXCIE1);

    UCSR1C |= (1<<URSEL1)|(1<<UCSZ10)| (1<<UCSZ11);    // Asynchron 8N1

  USART_Transmit('A');

  UART1_Transmit('A');

  sei();          //activate Interrupts

    TIMSK |= (1<<TOIE1);

    while(1)

    {

      if(wert_anfordern == 1)    //Wertanforderung

      {

        TR_PORT |= (1<<TR_PIN);

        USART_Transmit('B');

        USART_Transmit('C');

        UART1_Transmit('K');

        wert_anfordern = 0;

        TR_PORT &= ~(1<<TR_PIN);

      }

    }

}

UART1_Transmit('K');

TR_PORT &= ~(1<<TR_PIN);

#define TRANSMIT_ON() ... // Setze 75176 Pins 2,3 HIGH

#define TRANSMIT_OFF() ... //  Setze 75176 Pins 2,3 LOW

// internal

void uart_put(unsigned char c)

{

    while (!(UCSRA & (1<<UDRE))); // warte bis Sendepuffer leer

    UDR = c;

}

void uart_putc(unsigned char c)

{

    TRANSMIT_ON();

    uart_put(c);

    // warte bis kompletter Frame gesendet

    while (!(UCSRA & (1<<TXC))); 

    TRANSMIT_OFF();

}

void uart_puts (char *s)

{

    //

    // Fuer vernuenftige Halbduplex-Kommunikation muesste hier 

    // erstmal gepueft werden, ob gerade Daten empfangen werden!

    // Nur wenn der Bus frei ist darf gesendet werden.

    //

    // 75176 in Sendemodus

    TRANSMIT_ON();

    while (*s)

    {

        uart_put(*s);

        s++;

    }

    // warte bis kompletter Frame gesendet

    while (!(UCSRA & (1<<TXC))); 

    // 75176 in Empfangsmodus

    TRANSMIT_OFF();

}

#define TRANSMIT_ON    PORTC |= (1<<PC3)

#define TRANSMIT_OFF  PORTC &= ~(1<<PC3)

ISR(USART0_TXC_vect)

{

  TRANSMIT_OFF;

  UART1_Transmit('V');

}

void uart_putc(unsigned char c)

{

    TRANSMIT_ON;

    USART_Transmit(c);

}