/* ********************************************************************** 
 * 7-SegmentDisplay - v1.0
 *   Uses Common cathode 7-segment display,
 *   Uses 74HC595 shift register IC
 *   
 *
 * Description:
 *   This sketch illustrates the controlling a 7-segment display with
 *   a 74HC595 shift register.
 *   
 * See spreadsheet file 74HC595_SegmentDisplay.ods
 * Define the LED digit patterns, from 0 - 9
 * 1 = LED on, 0 = LED off, common cathode, in this order:
 *           74HC595 pin     Q7,Q6,Q5,Q4,Q3,Q2,Q1,Q0 
 *           Mapping to      dp,g,f,e,d,c,b,a of Seven-Segment LED
 *
 * NOTES:
 *  Add 330 ohm resistors to each segment pin of 7-segment display.
 *  Add a NPN transistor (2N2222) to each digit line of 74HC595. The collector goes to the display,
 *  the base goes to the shift register and the emitter goes to ground.
 * ********************************************************* */

 /*                    Hardware Definitions                   */

int latchPin = 11; // connect to the ST_CP of 74HC595 (pin 12,latch pin)
int clockPin = 9;  // connect to the SH_CP of 74HC595 (pin 11, clock pin)
int dataPin = 12;  // connect to the DS of 74HC595 (pin 14, data pin)

#define DIGITS 2


byte sevenSegDigits[10] = { B00111111   ,  // = 0
                            B00000110   ,  // = 1
                            B01011011   ,  // = 2
                            B01001111   ,  // = 3
                            B01100110   ,  // = 4
                            B01101101   ,  // = 5
                            B01111101   ,  // = 6
                            B00000111   ,  // = 7
                            B01111111   ,  // = 8
                            B01101111      // = 9
                           };

byte sevenSegDP = B10000000;  // = DP

int digit1, digit2, digit3, digit4;


/*                    Function Declaration                    */
void sevenSegWrite(byte digit);
void sevenSegSegment(byte digit);
void sevenSegBlank();

void showNumber(long, long);
int intLength(long);

void setup() {
  Serial.begin(9600);
  // Set latchPin, clockPin, dataPin as output
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);

  // really needed????
  digitalWrite(latchPin, LOW);
  digitalWrite(clockPin, LOW);
  digitalWrite(dataPin, LOW);


}


void loop() {


for (int i = 0; i < 10; i++) {
  int digitBits = B11111101;
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, digitBits);
    shiftOut(dataPin, clockPin, MSBFIRST, sevenSegDigits[i]);
    digitalWrite(latchPin, HIGH);
    delay(500);
  for (int j = 0; j < 10; j++) {
    int digitBits = B11111011; 
    digitalWrite(latchPin, LOW);
    shiftOut(dataPin, clockPin, MSBFIRST, digitBits);
    shiftOut(dataPin, clockPin, MSBFIRST, sevenSegDigits[j]);
    digitalWrite(latchPin, HIGH);
    delay(500);
  }
    
}


/*
  // This selects which digit to turn on. Common cathode uses a 0 to turn on a digit.
  // Below digit 1 is turned on, all other digits are turned off.
  int digitBits = B11111110; 
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, digitBits); 
  shiftOut(dataPin, clockPin, MSBFIRST, sevenSegDigits[0]);
  digitalWrite(latchPin, HIGH);    
  // Serial.print("Showing: ");Serial.println(digit1);
  delay(1);

  digitBits = B11111101;
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, digitBits);
  shiftOut(dataPin, clockPin, MSBFIRST, sevenSegDigits[1]);
  digitalWrite(latchPin, HIGH); 
  // Serial.print("Showing: ");Serial.println(digit2);               
  delay(1);

  digitBits = B11111011;
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, digitBits);
  shiftOut(dataPin, clockPin, MSBFIRST, sevenSegDigits[2]);
  digitalWrite(latchPin, HIGH); 
  // Serial.print("Showing: ");Serial.println(digit2);               
  delay(1);
*/

/*     
  // count from 9 to 0
  for (int digit = 9; digit >= 0; digit--) {
    sevenSegWrite(digit);
    delay(800);
  }
  // suspend 1 second
  sevenSegBlank();
  delay(800);
  
 
  // count from 0 to 9
  for (int digit = 0; digit <= 9; digit++) {
    sevenSegWrite(digit);
    delay(800);
  }
  // suspend 1 second
  sevenSegBlank();
  delay(800);

  
  for (int i = 0; i < 6; i++) {
    byte z = 0b00000000 + (1 << i);
    sevenSegSegment(z);
    delay(100);
  }
  for (int i = 0; i < 6; i++) {
    byte z = 0b00000000 + (1 << i);
    sevenSegSegment(z);
    delay(100);
  }
  for (int i = 0; i < 6; i++) {
    byte z = 0b00000000 + (1 << i);
    sevenSegSegment(z);
    delay(100);
  }

  for (int i = 0; i < 6; i++) {
    sevenSegSegment(sevenSegDP);
    delay(300);
    sevenSegBlank();
    delay(300);
  }

  // suspend 1 second
  sevenSegBlank();
  delay(1000);

*/

}

/* ***********************************************************
 *                         Functions                         *
 * ********************************************************* */ 
// display a alpha, binary value, or number on the digital segment display
void sevenSegWrite(byte digit) {
    //      digit = array pointer or binary value, as a byte 
  digitalWrite(latchPin, LOW); // set latchPin low, before sending data
  shiftOut(dataPin, clockPin, MSBFIRST, sevenSegDigits[digit]);
  digitalWrite(latchPin, HIGH); // set latchPin high, after sending data
}

void sevenSegSegment(byte digit) {
    //      digit = array pointer or binary value, as a byte 
  digitalWrite(latchPin, LOW); // set latchPin low, before sending data
  shiftOut(dataPin, clockPin, MSBFIRST, digit);
  digitalWrite(latchPin, HIGH); // set latchPin high, after sending data
}

void sevenSegBlank(){
  digitalWrite(latchPin, LOW); // set latchPin low, before sending data
  shiftOut(dataPin, clockPin, MSBFIRST, B00000000);  
  digitalWrite(latchPin, HIGH); // set latchPin high, after sending data
}