Spi_Master

#include <avr/io.h>
#define F_CPU 14745600UL //Clock speed - to be set seeing value of crystal
#include <util/delay.h>

#define baud 9600

#define UBRR ( F_CPU/16*baud - 1 )

void uart_init ()
{
	UBRRH = (unsigned char)(95>>8); //shifts the register right by 8 bits
	UBRRL = (unsigned char) 95;
	UCSRB = (1<<RXEN)|(1<<TXEN);            //Enable receiver and transmitter  
	// Set frame format: 8data, 2stop bit 
	UCSRC = (1<<URSEL)|(3<<UCSZ0); 
	  
}

void uart_transmit(unsigned char data)
{
	while (!( UCSRA & (1<<UDRE)));
	// UCSRA & (1<<UDRE) gives current value. UDRE = zero - indicates that buffer is empty 
	UDR = data; //data is now in buffer
}

unsigned char uart_receive( void )
{
	while (!(UCSRA & (1<<RXC))); 
	// RXC = 0 - indicates data is being received and stops program as long as data is being received 
	return UDR; //return data received in buffer
}
void SPI_MasterInit(void)
{
	// Set MOSI and SCK output, all others input 
	DDRB = 0b10110000;
	// Enable SPI, Master, set clock rate fck/16 
	SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);
}

void SPI_MasterTransmit(unsigned char cData)
{
	
	// Start transmission 
	SPDR = cData;
	// Wait for transmission complete 
	while(!(SPSR & (1<<SPIF)))
	;
}
unsigned char SPI_SlaveReceive(void)
{
	// Wait for reception complete
	while(!(SPSR & (1<<SPIF)))
	;
	// Return Data Register
	return SPDR;
}

int main(){
	uart_init ();
	SPI_MasterInit();
	unsigned char a,b;
	while(1)
{
        b=uart_receive();
		SPI_MasterTransmit(b);
	a =	SPI_SlaveReceive();
	
		uart_transmit(a);

	}
}