/*
  -------------------------------------------------------------
  Using the Arduino's output pins to display individual
  segments on a 7-segment display (SSD)!
  -------------------------------------------------------------
  SSD:			      Common Cathode

  Resistors:		  2 x 220 ohm resistors on top and bottom
				        middle pins, connect these to GND (-) rail
                on the breadboard
  -------------------------------------------------------------
  Arduino Pins:	  Pin 1 to Segment A on SSD
				        Pin 2 to Segment B on SSD
                Pin 3 to Segment C on SSD
                Pin 4 to Segment D on SSD
                Pin 5 to Segment E on SSD
                Pin 6 to Segment F on SSD
                Pin 7 to Segment G on SSD
                Pin 8 to decimal point on SSD

                5V to + rail on breadboard
                GND to - rail on breadboard
  -------------------------------------------------------------
  Note:		      	Run another wire from the bottom GND
				        (-) rail on the breadboard up to its
                counterpart at the top for the
                middle pin on the top of the SSD to
                connect to through a resistor.
  -------------------------------------------------------------
*/

// sets up the pins going from the Arduino to the SSG for
// use in the code later on!

const int a = 1;		// segment A on SSD (pin 1)
const int b = 2;
const int c = 3;
const int d = 4; 		// segment D on SSD (pin 4)
const int e = 5;
const int f = 6;
const int g = 7;		// segment G on SSD (pin 7)
const int p = 8;		// decimal point on SSD (pin 8)

void DoesItWork ()		// are all connections working?
{
  digitalWrite(a, HIGH);
  delay(50);
  digitalWrite(b, HIGH);
  delay(50);
  digitalWrite(c, HIGH);
  delay(50);
  digitalWrite(d, HIGH);
  delay(50);
  digitalWrite(e, HIGH);
  delay(50);
  digitalWrite(f, HIGH);
  delay(50);
  digitalWrite(g, HIGH);
  delay(50);
  digitalWrite(p, HIGH);
  delay(50);
}

void TurnMeOff ()		// turns all segments OFF
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(p, LOW);
  delay(50);
}

void setup ()			// all pins set to OUTPUT mode
{
  pinMode(a, OUTPUT);
  pinMode(b, OUTPUT);
  pinMode(c, OUTPUT);
  pinMode(d, OUTPUT);
  pinMode(e, OUTPUT);
  pinMode(f, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(p, OUTPUT);
}

void loop ()
{
  DoesItWork ();
  TurnMeOff ();
}