SPI - ATMEGA32

#define DDR_SPI DDRB

#define DD_MOSI PB5

#define DD_SCK PB7

void SPI_MasterInit(void)

{

/* Set MOSI and SCK output, all others input */

DDR_SPI = (1<<DD_MOSI)|(1<<DD_SCK);

/* Enable SPI, Master, set clock rate fck/16 */

SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);

}

void SPI_MasterTransmit(char cData)

{

/* Start transmission */

SPDR = cData;

/* Wait for transmission complete */

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

;

}

void main(void)

{

...

SPI_MasterInit();

SPI_MasterTransmit(0xA5);

SPI_MasterTransmit(0xAA);

SPI_MasterTransmit(0x55);

...

}