char buf[20];

void setup() {
  DDRD |= B11111111; PORTD = 0;
  DDRB |= B00111111; PORTB = B00111111;
  DDRC |= B00011111; PORTC = B00011111;

  sprintf(buf, "HELLO WORLD");
}

void loop() {

  unsigned long timer = millis();
  static unsigned long elapse = timer;

  static bool init = true;
  static long i = 2147483630;

  if (init)
  {
    if (timer - elapse > 3000)
    {
      elapse = timer; init = false;
    }
  }
  else
  {
    sprintf(buf, "%11ld", i);
    if (timer - elapse > 200)
    {
      elapse = timer; i++;
    }
  }

  digitalWrite( 8, LOW); PORTD = Test(buf[10]); digitalWrite( 8, HIGH); PORTD = 0;
  digitalWrite( 9, LOW); PORTD = Test(buf[ 9]); digitalWrite( 9, HIGH); PORTD = 0;
  digitalWrite(10, LOW); PORTD = Test(buf[ 8]); digitalWrite(10, HIGH); PORTD = 0;
  digitalWrite(11, LOW); PORTD = Test(buf[ 7]); digitalWrite(11, HIGH); PORTD = 0;
  digitalWrite(12, LOW); PORTD = Test(buf[ 6]); digitalWrite(12, HIGH); PORTD = 0;
  digitalWrite(13, LOW); PORTD = Test(buf[ 5]); digitalWrite(13, HIGH); PORTD = 0;
  digitalWrite(A0, LOW); PORTD = Test(buf[ 4]); digitalWrite(A0, HIGH); PORTD = 0;
  digitalWrite(A1, LOW); PORTD = Test(buf[ 3]); digitalWrite(A1, HIGH); PORTD = 0;
  digitalWrite(A2, LOW); PORTD = Test(buf[ 2]); digitalWrite(A2, HIGH); PORTD = 0;
  digitalWrite(A3, LOW); PORTD = Test(buf[ 1]); digitalWrite(A3, HIGH); PORTD = 0;
  digitalWrite(A4, LOW); PORTD = Test(buf[ 0]); digitalWrite(A4, HIGH); PORTD = 0;

}

uint8_t Test(uint8_t i)
{

  //  AAA
  // F   B
  // F   B
  //  GGG
  // E   C
  // E   C
  //  DDD .
  //

  switch (i)
  { //ASCII           .GFEDCBA
    case 48: return 0b00111111; // '0'
    case 49: return 0b00000110; // '1'
    case 50: return 0b01011011; // '2'
    case 51: return 0b01001111; // '3'
    case 52: return 0b01100110; // '4'
    case 53: return 0b01101101; // '5'
    case 54: return 0b01111101; // '6'
    case 55: return 0b00000111; // '7'
    case 56: return 0b01111111; // '8'
    case 57: return 0b01101111; // '9'
    case 32: return 0b00000000; // ' '  BLANK
    case 42: return 0b01100011; // '*'
    case 45: return 0b01000000; // '-'
    case 46: return 0b10000000; // '.'
    case 65: return 0b01110111; // 'A'
    case 66: return 0b01111100; // 'B' (b)
    case 67: return 0b00111001; // 'C'
    case 68: return 0b01011110; // 'D' (d)
    case 69: return 0b01111001; // 'E'
    case 70: return 0b01110001; // 'F'
    case 71: return 0b00111101; // 'G'
    case 72: return 0b01110110; // 'H'
    case 73: return 0b00110000; // 'I'
    case 74: return 0b00001110; // 'J'
    case 75: return 0b01110110; // 'K'  Same as 'H'
    case 76: return 0b00111000; // 'L'
    case 77: return 0b00000000; // 'M'  NO DISPLAY
    case 78: return 0b01010100; // 'N' (n)
    case 79: return 0b00111111; // 'O'
    case 80: return 0b01110011; // 'P' (p)
    case 81: return 0b01100111; // 'Q' (q)
    case 82: return 0b01010000; // 'R' (r)
    case 83: return 0b01101101; // 'S'
    case 84: return 0b01111000; // 'T' (t)
    case 85: return 0b00111110; // 'U'
    case 86: return 0b00111110; // 'V'  Same as 'U'
    case 87: return 0b01111110; // 'W'  
    case 88: return 0b01110110; // 'X'  Same as 'H'
    case 89: return 0b01101110; // 'Y' (y)
    case 90: return 0b01011011; // 'Z'  Same as '2'
    case 95: return 0b00001000; // '_'  UNDERSCORE
    default: return 0b00000000;
  }
}