unsigned char rcvd[5];
unsigned char send[]={1,2,3,4,5};
unsigned char count=0;
unsigned char junk;

void spi_init(void)
{
SPCR=0xf2;			// SPE, DORD, MSTR, CPOL, SPR1 Set
SPSR=0x01;			// SPI2x Set 

}



<----------------------------------- Polling example ---------------------------------------------------------->

void runspi(void)
{
int i;
for (i=0; i<5;i++)				// Send out 5 bytes of data by loading it on the SPDR
{								// Note that the STC interrupt will execute on transmission complete,
PORTC=send[i];					// thus we need not worry about losing incoming data
while(SPI_BSY);					// Do nothing till the SPI section is busy
    junk = SPSR;				// Necessary to read SPSR to clear SPIF after transmission and then 
	rcvd[i]=SPDR;				// read the SPI Data register. Both of these must be executed and in this order.
}								
}


    
   

<----------------------------------- Interrupt example ---------------------------------------------------------->

ISR(SPI_STC_vect)
{
rcvd[count] = SPDR; 			// SPIF cleared automatically when the interrupt is executed
count++;
}

void runspi(void)
{
int i;
for (i=0; i<5;i++)				// Send out 5 bytes of data by loading it on the SPDR
{								// Note that the STC interrupt will execute on transmission complete,
PORTC=send[i];					// thus we need not worry about losing incoming data
}								
}