48 x 8 Scrolling LED Matrix using Arduino.

/*////////////////////////////////////////////////////////////////////////////////
 * Arduino code to display scrolling characters on 6 or more 8x8 LED matrix.    *
 * The no: of matrices can be increased with a small change in code.            *
 * Comments are given in each statement for editing.                            *
 * Coded by Prasanth K S                           *
 * Contact : kksjunior@hotmail.com                                          *
/*////////////////////////////////////////////////////////////////////////////////

char msg[] ="WELCOME WIZ";//Change the text here.
int scrollspeed=5;//Set the scroll speed ( lower=faster)

int x;
int y;

//Columns
int clockPin1 = 2; //Arduino pin connected to Clock Pin 11 of 74HC595
int latchPin1 = 3; //Arduino pin connected to Latch Pin 12 of 74HC595
int dataPin1 = 4;  //Arduino pin connected to Data Pin 14 of 74HC595

//Rows
int clockPin2 = 5; //Arduino pin connected to Clock Pin 11 of 74HC595
int latchPin2 = 6; //Arduino pin connected to Latch Pin 12 of 74HC595
int dataPin2 = 7;  //Arduino pin connected to Data Pin 14 of 74HC595

//BITMAP
//Bits in this array represents one LED of the matrix
// 8 is # of rows, 6 is # of LED matrices
byte bitmap[8][7]; 

int numZones = sizeof(bitmap) / 8; // One Zone refers to one 8 x 8 Matrix ( Group of 8 columns)
int maxZoneIndex = numZones-1;
int numCols = numZones * 8;

//FONT DEFENITION
byte alphabets[][8] = {
 {0,0,0,0,0},//@ as SPACE
 //{8,28,54,99,65},//<<
 {31, 36, 68, 36, 31},//A
 {127, 73, 73, 73, 54},//B
 {62, 65, 65, 65, 34},//C
 {127, 65, 65, 34, 28},//D
 {127, 73, 73, 65, 65},//E
 {127, 72, 72, 72, 64},//F
 {62, 65, 65, 69, 38},//G
 {127, 8, 8, 8, 127},//H
 {0, 65, 127, 65, 0},//I
 {2, 1, 1, 1, 126},//J
 {127, 8, 20, 34, 65},//K
 {127, 1, 1, 1, 1},//L
 {127, 32, 16, 32, 127},//M
 {127, 32, 16, 8, 127},//N
 {62, 65, 65, 65, 62},//O
 {127, 72, 72, 72, 48},//P
 {62, 65, 69, 66, 61},//Q
 {127, 72, 76, 74, 49},//R
 {50, 73, 73, 73, 38},//S
 {64, 64, 127, 64, 64},//T
 {126, 1, 1, 1, 126},//U
 {124, 2, 1, 2, 124},//V
 {126, 1, 6, 1, 126},//W
 {99, 20, 8, 20, 99},//X
 {96, 16, 15, 16, 96},//Y
 {67, 69, 73, 81, 97},//Z
};

void setup() {
 pinMode(latchPin1, OUTPUT);
 pinMode(clockPin1, OUTPUT);
 pinMode(dataPin1, OUTPUT);

 pinMode(latchPin2, OUTPUT);
 pinMode(clockPin2, OUTPUT);
 pinMode(dataPin2, OUTPUT);
 
 //Clear bitmap
 for (int row = 0; row < 8; row++) {
   for (int zone = 0; zone <= maxZoneIndex; zone++) {
     bitmap[row][zone] = 0; 
   }
 }
}

//FUNCTIONS
// Displays bitmap array in the matrix
void RefreshDisplay()
{
 for (int row = 0; row < 8; row++) {
   int rowbit = 1 << row;
   digitalWrite(latchPin2, LOW);//Hold latchPin LOW for transmitting data
   shiftOut(dataPin2, clockPin2, MSBFIRST, rowbit);   //Transmit data

   //Start sending column bytes
   digitalWrite(latchPin1, LOW);//Hold latchPin LOW for transmitting data

   //Shift out to each matrix
   for (int zone = maxZoneIndex; zone >= 0; zone--) 
   {
     shiftOut(dataPin1, clockPin1, MSBFIRST, bitmap[row][zone]);
   }

   //flip both latches at once to eliminate flicker
   digitalWrite(latchPin1, HIGH);//Return the latch pin 1 high to signal chip
   digitalWrite(latchPin2, HIGH);//Return the latch pin 2 high to signal chip

   //Wait
   delayMicroseconds(300);
 }
}

// Converts row and colum to bitmap bit and turn it off/on
void Plot(int col, int row, bool isOn)
{
 int zone = col / 8;
 int colBitIndex = x % 8;
 byte colBit = 1 << colBitIndex;
 if (isOn)
   bitmap[row][zone] =  bitmap[y][zone] | colBit;
 else
   bitmap[row][zone] =  bitmap[y][zone] & (~colBit);
}
// Plot each character of the message one column at a time, updated the display, shift bitmap left.
void XProcess()
{
 for (int charIndex=0; charIndex < (sizeof(msg)-1); charIndex++)
 {
   int alphabetIndex = msg[charIndex] - '@';
   if (alphabetIndex < 0) alphabetIndex=0;
   
   //Draw one character of the message
   // Each character is 5 columns wide, loop two more times to create 2 pixel space betwen characters
   for (int col = 0; col < 7; col++)
   {
     for (int row = 0; row < 8; row++)
     {
       // Set the pixel to what the alphabet say for columns 0 thru 4, but always leave columns 5 and 6 blank.
       bool isOn = 0; 
       if (col<5) isOn = bitRead( alphabets[alphabetIndex][col], 7-row ) == 1;
       Plot( numCols-1, row, isOn); //Draw on the rightmost column, the shift loop below will scroll it leftward.
     }
     for (int refreshCount=0; refreshCount < scrollspeed; refreshCount++)
       RefreshDisplay();
     //Shift the bitmap one column to left
     for (int row=0; row<8; row++)
     {
       for (int zone=0; zone < numZones; zone++)
       {
         //This right shift would show as a left scroll on display because leftmost column is represented by least significant bit of the byte.
         bitmap[row][zone] = bitmap[row][zone] >> 1;
         // Shift over lowest bit from the next zone as highest bit of this zone.
         if (zone < maxZoneIndex) bitWrite(bitmap[row][zone], 7, bitRead(bitmap[row][zone+1],0));
       }
     }
   }
 }
}
void loop() {
 XProcess();
}