#include <avr/io.h>
#define F_CPU 8000000UL
#include <util/delay.h>

/* Übertragung vom ATMega16 zum AD9835

 ATMega16 :	       	AD9835:
PB7	 SCK	=>	SCLK  
PB5	 MOSI   =>	SDATA
PB4	 SS	=>	FSYNC

*/







void SPI_MasterInit(void)
{
 // PB7 = SCLK  und  PB5 = MOSI und  PB4 = SS		

	DDRB = 0b10110000;  			
	
	SPCR =  (1<<SPE) | (1<<MSTR) | (1<<SPR0)  |(1<<CPHA) ; 
											               							
}

void SPI_MasterTransmit(unsigned char data)
{
	
	SPDR = data;

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

void Send_Word(uint16_t word)    //SPI - Übertragung zum AD9835 
{
	PORTB = PORTB | (1<<PB4); 
	SPI_MasterTransmit(((word&0xFF00)>> 8)); //MSB
	SPI_MasterTransmit(word);		 //LSB
	PORTB = PORTB & ~(1<<PB4);
}



int main(void)
{	

	uint16_t data = 0xFFFE;

	SPI_MasterInit();

	
	
	while(1)
	{
		Send_Word(data);
		_delay_ms(1);
	}
}