#define Slave_Select  9

void setup(){
  SPI.setBitOrder(MSBFIRST);
  SPI.setClockDivider(SPI_CLOCK_DIV2); //SPI @ 8MHz
  SPI.begin();
  pinMode(Slave_Select,OUTPUT);
  digitalWrite(Slave_Select,HIGH);
}

void loop(){
  digitalWrite(Slave_Select,LOW);
  SPI.transfer(B10101010);
  SPI.transfer(B01010101);
  digitalWrite(Slave_Select,HIGH);
}