Walking bit on 8*8 LED Matrix, with Arduino Uno

Last post have a 8*8 LED Matrix, work with Arduino Uno.

It's another test program to turn ON/OFF a walking bit on 8*8 LED Matrix, to clarify all LED work as expect.

/*
 *  Modify from Row-Column Scanning an 8x8 LED matrix tutorial
 *  http://arduino-er.blogspot.com/
 */
/*
  Row-Column Scanning an 8x8 LED matrix with X-Y input

 This example controls an 8x8 LED matrix using two analog inputs

 created 27 May 2009
 modified 30 Aug 2011
 by Tom Igoe

 This example works for the Lumex  LDM-24488NI Matrix. See
 http://sigma.octopart.com/140413/datasheet/Lumex-LDM-24488NI.pdf
 for the pin connections

 For other LED cathode column matrixes, you should only need to change
 the pin numbers in the row[] and column[] arrays

 rows are the anodes
 cols are the cathodes
 ---------

 Pin numbers:
 Matrix:
 * Digital pins 2 through 13,
 * analog pins 2 through 5 used as digital 16 through 19
 Potentiometers:
 * center pins are attached to analog pins 0 and 1, respectively
 * side pins attached to +5V and ground, respectively.

 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/RowColumnScanning

 see also http://www.tigoe.net/pcomp/code/category/arduinowiring/514 for more
 */


// 2-dimensional array of row pin numbers:
const int row[8] = {
  2, 7, 19, 5, 13, 18, 12, 16
};

// 2-dimensional array of column pin numbers:
const int col[8] = {
  6, 11, 10, 3, 17, 4, 8, 9
};

// 2-dimensional array of pixels:
int pixels[8][8];

int posX = 7;
int posY = 7;
int count = 30;
bool bg = false;

void setup() {
  // initialize the I/O pins as outputs
  // iterate over the pins:
  for (int thisPin = 0; thisPin < 8; thisPin++) {
    // initialize the output pins:
    pinMode(col[thisPin], OUTPUT);
    pinMode(row[thisPin], OUTPUT);
    // take the col pins (i.e. the cathodes) high to ensure that
    // the LEDS are off:
    digitalWrite(col[thisPin], HIGH);
  }

  setupScreen();

}

void loop() {

  // draw the screen:
  refreshScreen();
  
  if(count-- == 0){
    count = 500;
    if(posX--==0){
      posX = 7;
      if(posY--==0){
        posY = 7;
        bg = !bg;
      }
    }
    setupScreen();

  }
}

void setupScreen(){
  if(bg){
    //ON all others
    for (int x = 0; x < 8; x++) {
      for (int y = 0; y < 8; y++) {
        pixels[x][y] = LOW;
      }
    }
    
    //OFF current pos
    pixels[posX][posY] = HIGH;
  }else{
    //OFF all others
    for (int x = 0; x < 8; x++) {
      for (int y = 0; y < 8; y++) {
        pixels[x][y] = HIGH;
      }
    }
    
    //ON current pos
    pixels[posX][posY] = LOW;
  }
}

void refreshScreen() {
  // iterate over the rows (anodes):
  for (int thisRow = 0; thisRow < 8; thisRow++) {
    // take the row pin (anode) high:
    digitalWrite(row[thisRow], HIGH);
    // iterate over the cols (cathodes):
    for (int thisCol = 0; thisCol < 8; thisCol++) {
      // get the state of the current pixel;
      int thisPixel = pixels[thisRow][thisCol];
      // when the row is HIGH and the col is LOW,
      // the LED where they meet turns on:
      digitalWrite(col[thisCol], thisPixel);
      // turn the pixel off:
      if (thisPixel == LOW) {
        digitalWrite(col[thisCol], HIGH);
      }
    }
    // take the row pin low to turn off the whole row:
    digitalWrite(row[thisRow], LOW);
  }
}