ArduinoShiftRegister.ino

#include <SPI.h>

#define SHIFT_REGISTER_CS 5

void setup()  { 
  // SPI
  SPI.begin();
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE0);
  SPI.setClockDivider(SPI_CLOCK_DIV2);
  pinMode(SHIFT_REGISTER_CS, OUTPUT);
  digitalWrite(SHIFT_REGISTER_CS, HIGH);
} 

void loop(){
  for(int i=0; i<=8; i++){
    unsigned char out = 0xFF >> i;
    outputToShiftRegister(out);
    delay(50);
  }
  for(int i=8; i>=0; i--){
    unsigned char out = 0xFF >> i;
    outputToShiftRegister(out);
    delay(50);
  }
}

void outputToShiftRegister(unsigned char data){
  digitalWrite(SHIFT_REGISTER_CS, LOW);
  SPI.transfer(data);
  digitalWrite(SHIFT_REGISTER_CS, HIGH);  
}