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//**************************************************************//
//  Name    : shiftOutCode, One By One                          //
//  Author  : Carlyn Maw, Tom Igoe                           //
//  Date    : 25 Oct, 2006                                      //
//  Version : 1.0                                               //
//  Notes   : Code for using a 74HC595 Shift Register           //
//          : to count from 0 to 255                            //
//****************************************************************

//Pin connected to ST_CP of 74HC595
int latchPin = 8;
//Pin connected to SH_CP of 74HC595
int clockPin = 12;
////Pin connected to DS of 74HC595
int dataPin = 11;

//holder for infromation you're going to pass to shifting function
byte data = 0; 



void setup() {
  //set pins to output because they are addressed in the main loop
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);

}

void loop() {

  //function that blinks all the LEDs
  //gets passed the number of blinks and the pause time
  blinkAll(1,500); 

 // light each pin one by one using a function A
  for (int j = 0; j < 8; j++) {
    lightShiftPinA(j);
    delay(1000);
  }

  blinkAll(2,500);  

 // light each pin one by one using a function A
  for (int j = 0; j < 8; j++) {
    lightShiftPinB(j);
    delay(1000);
  } 

}

//This function uses bitwise math to move the pins up
void lightShiftPinA(int p) {
  //defines a local variable
  int pin;

  //this is line uses a bitwise operator
  //shifting a bit left using << is the same
  //as multiplying the decimal number by two. 
  pin = 1<< p;

  //ground latchPin and hold low for as long as you are transmitting
  digitalWrite(latchPin, LOW);
  //move 'em out
  shiftOut(dataPin, clockPin, MSBFIRST, pin);   
  //return the latch pin high to signal chip that it 
  //no longer needs to listen for information
  digitalWrite(latchPin, HIGH);

}

//This function uses that fact that each bit in a byte
//is 2 times greater than the one before it to
//shift the bits higher
void lightShiftPinB(int p) {
  //defines a local variable
  int pin;

  //start with the pin = 1 so that if 0 is passed to this
  //function pin 0 will light. 
  pin = 1;

  for (int x = 0; x < p; x++) {
    pin = pin * 2; 
  }

  //ground latchPin and hold low for as long as you are transmitting
  digitalWrite(latchPin, LOW);
  //move 'em out
  shiftOut(dataPin, clockPin, MSBFIRST, pin);   
  //return the latch pin high to signal chip that it 
  //no longer needs to listen for information
  digitalWrite(latchPin, HIGH);

}


//blinks the whole register based on the number of times you want to 
//blink "n" and the pause between them "d"
//starts with a moment of darkness to make sure the first blink
//has its full visual effect.
void blinkAll(int n, int d) {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, 0);
  digitalWrite(latchPin, HIGH);
  delay(200);
  for (int x = 0; x < n; x++) {
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 255);
    digitalWrite(latchPin, HIGH);
    delay(d);
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, 0);
    digitalWrite(latchPin, HIGH);
    delay(d);
  }
}