#include "LedControl.h"

const byte DIR_PIN = 12;      // D12 connected to MAX7219 DIN (pin 1)
const byte CLK_PIN = 11;      // D11 connected to MAX7219 CLK (pin 13)
const byte LOAD_PIN = 10;     // D10 connected to MAX7219 LOAD (pin 12)
const byte MATRIX_SIZE = 8;   // 8 MAX7219's
const byte MATRIX_BRT = 2;    // Brightness

LedControl lc = LedControl(DIR_PIN, CLK_PIN, LOAD_PIN, MATRIX_SIZE);

void setup() {
  for (int devNum = 0; devNum < MATRIX_SIZE; devNum++)  {
    lc.shutdown(devNum, false);           // turn off power saving, enables matrices
    lc.setIntensity(devNum, MATRIX_BRT);  // sets brightness (0~15 possible values)
    lc.clearDisplay(devNum);              // clear matrices
  }
}

void loop() {
  for (int row = 0; row < MATRIX_SIZE; row++) {
    for (int devNum = MATRIX_SIZE - 1; devNum >= 0; devNum--)  {
      for (int col = MATRIX_SIZE - 1; col >= 0; col--) {
        lc.setLed(devNum, row, col, true);  // turns off LED at col, row
        delay(25);
      }
    }
  }
  for (int row = MATRIX_SIZE - 1; row >= 0; row--) {
    for (int devNum = 0; devNum < MATRIX_SIZE; devNum++)  {
      for (int col = 0; col < MATRIX_SIZE; col++) {
        lc.setLed(devNum, row, col, false);  // turns on LED at col, row
        delay(25);
      }
    }
  }
}