ATmega128 und SPI Problem

  SPCR = (1<<MSTR);                // Set as Master

  SPCR = (1<<SPE);                // Enable SPI

#include "global.h"          // Globale Lib

int main(void)

{

  char data;         //Received data stored here

  cli();            // Disable all interrupts

  spi_init_master();      // SPI Inizalisierung

//  spi_init_slave ();

  initPort();          // Inizalisierung der Ports

  sei();            // enable all interrupts

while(1)

    {

  SWITCH_LED1;

  _delay_ms(500);

  data = 0x00;                    //Reset ACK in "data"

    data = spi_tranceiver('Hallo', PIN_SPI_CS1);

  SET_LED3;

  }

}

in der global.h

// SPI

#define PORT_SPI    PORTB

#define DDR_SPI      DDRB

#define PIN_SPI_MISO  3    // PB3

#define PIN_SPI_MOSI  2    // PB2

#define PIN_SPI_SCK    1    // PB1

#define PORT_SPI_CS    PORTC

#define DDR_SPI_CS    DDRC

#define PIN_SPI_CS1    7    // PC7

#define PIN_SPI_CS2    6    // PC6

#define PIN_SPI_CS3    5    // PC5

in der spi_master_slave.c

/*

 * spi_master_slave.c

 *

 * Created: 12.02.2015 14:08:46

 *  Author: u308488

 */

#include "spi_master_slave.h"

/*

// SPI Transmission/reception complete ISR

ISR(SPI_STC_vect)

{

    // Code to execute

    // whenever transmission/reception

    // is complete.

}

*/

void spi_init_slave (void)

{

   DDR_SPI |= (1<<PIN_SPI_MISO);    // MISO als Ausgang definieren

   SPCR |= (1<<SPE);                    //Enable SPI

}

//Initialize SPI Master Device

void spi_init_master (void)

{

  DDR_SPI = (1<<PIN_SPI_MOSI) | (1<<PIN_SPI_SCK); // MOSI und SCK als 

Ausgang definieren

  DDR_SPI &= ~(1<<PIN_SPI_MISO);          // MISO als Eingang definieren

  PORT_SPI = (1<<PIN_SPI_MOSI) | (1<<PIN_SPI_SCK);

//  SPCR = (1<<SPR1)|(1<<SPR0);            // Prescaler: Fosc/128, 

Enable Interrupts

//  SPCR = (1<<SPI2X);                // Prescaler: Fosc/2,

  SPCR = (1<<MSTR);                // Set as Master

  SPCR = (1<<SPE);                // Enable SPI

  //  SPCR = (1<<SPIE);              // SPI Interrupt Enable

  SPSR |= (0 << SPIF); // SPIF zum Start löschen

  _delay_ms(10);

}

//Function to send and receive data

char spi_tranceiver (char data, unsigned char cs)

{

  PORT_SPI_CS &= ~(1<<cs);    //SS am Slave Low --> Beginn der Übertragung

  SWITCH_LED2;

    SPDR = data;                       //Load data into the buffer

    while(!(SPSR & (1<<SPIF)));     //Wait until transmission complete

  PORT_SPI_CS |= (1<<cs);      //SS High --> Ende der Übertragung

  return SPDR;                     //Return received data

}