DIYTJ Module and Arduino

/*

Sergei A. Minayev, 2013
DIYTJ LED Matrix Module test app
Working app: http://youtu.be/R10uR81O0YM

*/

const int aPin = 2;
const int bPin = 3;
const int cPin = 4;
const int dPin = 5;
const int oePin = 9;
const int redPin = 8;
const int greenPin = 7;
const int strPin = 11;
const int sckPin = 12;

int row = 0;
int count = 0;
int number, i = 0;
int dig1, dig2, dig3, dig4 = 0;

// brutal font, zero element is 0; first element is 1 and so on...
byte numbers[][16] = {
    {B00000000, B01111110, B01111110, B01100110, B01100110, B01100110, B01100110, B01100110, B01100110, B01100110, B01100110, B01100110, B01100110, B01111110, B01111110, B00000000}, // 0
    {B00000000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00011000, B00000000}, // 1
    {B00000000, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B01111110, B01111110, B01100000, B01100000, B01100000, B01100000, B01111110, B01111110, B00000000}, // 2
    {B00000000, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B01111110, B01111110, B00000000}, // 3
    {B00000000, B01100110, B01100110, B01100110, B01100110, B01100110, B01100110, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000000}, // 4
    {B00000000, B01111110, B01111110, B01100000, B01100000, B01100000, B01100000, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B01111110, B01111110, B00000000}, // 5
    {B00000000, B01111110, B01111110, B01100000, B01100000, B01100000, B01100000, B01111110, B01111110, B01100110, B01100110, B01100110, B01100110, B01111110, B01111110, B00000000}, // 6
    {B00000000, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000110, B00000000}, // 7
    {B00000000, B01111110, B01111110, B01100110, B01100110, B01100110, B01100110, B01111110, B01111110, B01100110, B01100110, B01100110, B01100110, B01111110, B01111110, B00000000}, // 8
    {B00000000, B01111110, B01111110, B01100110, B01100110, B01100110, B01100110, B01111110, B01111110, B00000110, B00000110, B00000110, B00000110, B01111110, B01111110, B00000000}, // 9
  };

void setup() {
  //set pins to output because they are addressed in the main loop
  pinMode(aPin, OUTPUT);
  pinMode(bPin, OUTPUT);
  pinMode(cPin, OUTPUT);
  pinMode(dPin, OUTPUT);
  pinMode(oePin, OUTPUT);
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(strPin, OUTPUT);
  pinMode(sckPin, OUTPUT);
  digitalWrite(oePin, LOW);
}

void loop() {

  // DIYJT panel code --- start ---
  digitalWrite(oePin, HIGH);
  PORTD = (row << 2) & B00111100;
  digitalWrite(greenPin, HIGH);
  digitalWrite(strPin, LOW);
  shiftOut(redPin, sckPin, MSBFIRST, ~(numbers[dig1][row]));
  shiftOut(redPin, sckPin, MSBFIRST, ~(numbers[dig2][row]));
  shiftOut(redPin, sckPin, MSBFIRST, ~(numbers[dig3][row]));
  shiftOut(redPin, sckPin, MSBFIRST, ~(numbers[dig4][row]));

  digitalWrite(strPin, HIGH);
  digitalWrite(oePin, LOW);

  if (row <= 14) row++; else row = 0;

  // DIYJT panel code --- end ---

  // counter code --- start ---

  if (count<=999) count++; else {
    count = 0;
    if (number<=9999) number++; else number = 0;
    i = number;
    dig1 = i/1000;
    i = i-(dig1*1000);
    dig2 = i/100;
    i = i-(dig2*100);
    dig3 = i/10;
    i = i-(dig3*10);
    dig4 = i;
  }

  // counter code --- end ---


  delayMicroseconds(500);

}