Mega32 SPI Master hängt sich auf?

while(!(SPSR & (1<<SPIF)));

typedef unsigned char BYTE;

typedef unsigned short WORD;

// Settings for SPI

#define SPI_PORT        PORTB

#define SPI_PORT_DIR    DDRB

#define MISO            6

#define MOSI            5

#define SCK             7

void SPI_MasterInit(void)

{

  /* Set MOSI and SCK output, all others input */

  // Set SPI Pins

  SPI_PORT_DIR |= (1<<MOSI);      // SPI_PORT_DIR.MOSI = Output

    SPI_PORT_DIR &= ~(1<<MISO);      // SPI_PORT_DIR.MISO = Input

    SPI_PORT_DIR |= (1<<SCK);      // SPI_PORT_DIR.SCK = Output

    SPI_PORT_DIR |= (1<<PB4);      // SPI_PORT_DIR.PB4 = Output

  /* Enable SPI, Master, set clock rate fck/2 */

    // Master, full Speed, Mode 0, MSB first

    SPCR |= (1<<SPE)|(1<<MSTR);

    SPCR &= ~(1<<SPR0)|(1<<SPR1);

    SPSR |= (1<<SPI2X);

    //PORTB |= (1 << PB7)|(1 << PB4);

}

void send_byte(BYTE cData)

{

  /* Start transmission */

  char buffer[7];

  lcd_clrscr();

  //PORTB &= ~(1 << PB4);  // set chip select to low

  SPDR = cData;

  itoa(cData, buffer, 16); // Hex

  lcd_puts(buffer);

  lcd_gotoxy(0,1);

  lcd_puts("Daten im Speicher\n");

  /* Wait for transmission complete */

  while(!(SPSR & (1<<SPIF)));

  lcd_puts("Übertragung fertig");

}

int main(void) 

{

        sei();

        BYTE test= 0x0F;

        send_byte(test);

        for(;;)

        {

        }

}