hw spi atmega16

#include <avr/io.h>

#include <avr/interrupt.h>

#include <avr/pgmspace.h>

#include <avr/eeprom.h>

#include <stdlib.h>  

#define F_CPU 8000000UL

#include <util/delay.h>

#define SPI_PORT PORTB

#define SPI_DDR  DDRB

#define SPI_PIN  PINB

#define SPI_SDI  5

#define SPI_SCK  7

#define SPI_CS  4

#define SPI_SDO   6

unsigned short spi_Trans(unsigned short data)

{

    uint8_t highbyte;

    uint8_t lowbyte;

    lowbyte = data;

    highbyte = (data >> 8);

    SPI_PORT &= ~(1 << SPI_CS);  //vorsichtshalber SS selber setzen

    SPDR = highbyte;

    // Wait for transmission complete 

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

    ;

    SPI_PORT |= (1 << SPI_CS); // SS zurücksetzen

    SPI_PORT &= ~(1 << SPI_CS);    //vorsichtshalber SS selber setzen

    SPDR = lowbyte;

    // Wait for transmission complete 

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

    ;

    SPI_PORT |= (1 << SPI_CS); // SS zurücksetzen

    _delay_ms(1);

    return SPDR;

}

void spi_InitPort(void)

{

    SPI_DDR=(1<<SPI_SDI)|(1<<SPI_SCK)|(1<<SPI_CS);

    SPI_PORT=(1<<SPI_CS);

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

}

int main(void)

{

    spi_InitPort();

    spi_Trans(0xA000);

}