void SPI_MasterInit(void)
{   // Set MOSI and SCK output, all others input 
	DDR_SPI = (1<<DD_MOSI)|(1<<DD_SCK)|(1<<DD_SS);
	DDR_SPI &= ~(1<<DD_MISO); //MISO Eingang 
	//Enable SPI, Master, set clock rate fck/16 
	SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR1)|(1<<CPHA); //DORD Bit = 0 -> MSB wird zuerst übertragen; SPI Modus 1 (CPHA=1, CPOL=0)
	
}

void SPI_MasterTransmit(char cdata)
{   	PORTB &= ~(1<<DD_SS);
	_delay_ms(1);
	PORTB &= ~(1<<CS);
	
	// Start transmission 
	SPDR = cdata;
	
	// Wait for transmission complete 
	while(!(SPSR & (1<<SPIF)));
	
	PORTB |= (1<<DD_SS);
	PORTB |= (1<<CS);
}

char SPI_MasterReceive(void)
{	
	
	/* Wait for reception complete */
	while(!(SPSR & (1<<SPIF)))
	;
	/* Return data register */
	return SPDR;
}

void init_6675(void){													//AVR initialisieren

	SO_DDR &= ~(1 << SO);
	CS_DDR |= (1 << CS);
	SCK_DDR |= (1 << SCK);												//IOs setzen
	SO_Port |= (1<<SO);													//Pullups an. (Wichtig für MAX6675, der kann nicht anders, hab ich festgestellt...
	CS_Port |= (1 << CS);												//CS HI	//Alles auf Standardkonfig.
	SCK_Port &= ~(1 << SCK);											//SCK LO
}

int main(void)
{	
	 
	init_6675();
	SPI_MasterInit();
	
	
	while(1)
	{
		
		SPI_MasterTransmit(0x03);
		SPCR&= ~(1<<SPIF);
		SPI_MasterReceive();
		
		
	}
}