//------------------------------------------------------------------------------------------
//SPI HEADER
#define SS_PIN PB2
#define SS_PORT PORTB
#define SS_DDR_SET DDRB |= (1<<SS_PIN);


#define SS_HIGH          SS_PORT |= (1<<SS_PIN);
#define SS_LOW           SS_PORT &= ~(1<<SS_PIN);
//------------------------------------------------------------------------------------------
//SPI CODE
void init_spi(void)
{
	SS_DDR_SET//SS-Pin als Output
	DDRB |= (1<<PB3) | (1<<PB5);//MOSI und SCK Atmega8 als Output
	DDRB &= ~(1<<PB4);//MISO Atmega8 als Input

	SPCR |= (1<<SPE);//SPI ON
	SPCR |= (1<<MSTR);//als Master
	SPCR &= ~(1<<SPR0) | (1<<SPR1);//Prescaler 7372800 / 4 = 1,8432 MHz
	SPCR |= (1<<SPIE);//Interrupt ON
	
	//SPCR |= (1<<DORD);//LSB first transmittet
	SPCR &= ~(1<<DORD);//MSB first transmittet	

	SPCR |= (1<<CPOL) | (1<<CPHA);//SCK idle High, Data latched on rising Edge

	uint8_t reg1 = SPSR;//clear SPI-Interrupt by reading SPSR
	uint8_t reg2 = SPDR;//clear SPI-Interrupt by reading SPDR
}
............................................................................................
void send_spi(uint8_t val)
{	
	SS_LOW
	
	// Command Byte
	SPDR = 0b00010001;//Write Poti0
	while(!(SPSR & (1<<SPIF))){}//     Hier hängt sich der Controller auf,
	//SPI_FLAG_ZERO             //     er tut es nicht wenn diese Zeile auskommentiert ist
	
	//Data Byte
	SPDR = val;
	while(!(SPSR & (1<<SPIF))){}//     Hier ebenfalls
	//SPI_FLAG_ZERO

	SS_HIGH

return;
}