void setup()
{
  volatile char *dirf, *dirl;
  Serial.begin(9600);
  volatile char *outf, *outl;
  
  dirf = 0x30; // Port direction register for columns
  dirl = 0x10A; // Port direction register for rows
  outf = 0x31; // Port output register for columns
  outl = 0x10B; // Port output register for rows
  
  *dirf = 0xFF; // Set all column pins as output
  *dirl = 0xFF; // Set all row pins as output

  // Character bit patterns for scrolling (7 rows, 24 columns of data)
  volatile unsigned char arrf[7][24] = {
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc3, 0xc3, 0xc3, 0xc3, 0xdb, 0xff, 0xe7, 0xc3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xc0, 0xff, 0xff, 0xc0, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xc0, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x3f, 0x60, 0x60, 0x60, 0x60, 0x3f, 0x1f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c, 0x7e, 0xc3, 0xdb, 0xdb, 0xc3, 0x7e, 0x3c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0xc3, 0xe7, 0xff, 0xdb, 0xc3, 0xc3, 0xc3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xc0, 0xff, 0xff, 0xc0, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
  };

  // Row selection bits
  volatile char arrl[8] = {0x7f, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd, 0xfe};

  // Main loop for scrolling display
  while (1)
  {
    volatile int i, r, colShift;
    volatile long j, c;
    c = 50; // Delay counter for scrolling

    // Loop through each row of character data
    for (r = 0; r < 7; r++)
    {
      // Shift through 24 columns to simulate scrolling
      for (colShift = 0; colShift < 16; colShift++) // Adjust scroll length (16 fits well)
      {
        // Set delay to control speed of scrolling
        while (c-- > 0)
        {
          // Display each row, one row at a time
          for (i = 0; i < 8; i++) // Row selection (8 rows total)
          {
            *outl = arrl[7-i]; // Activate the row
            *outf = arrf[r][23 - i - colShift]; // Output shifted column data for scrolling
            
            // Short delay for each refresh cycle
            for (j = 0; j < 1000; j++); // Small delay
            *outf = 0x00; // Clear output
            *outl = 0xFF; // Reset rows
          }
        }
        c = 50; // Reset scroll delay after each full column shift
      }
    }
  }
}

void loop() {}