LED Matrix Count program

DisplayCount.cpp

/**
*  Program name:    This program is part of the project Pen Stand: LED Enabled
*  Author:          Aditya K
*  Date:            7/1/2017
*  LICENSE:         MIT
*
*  Discription: This program counts how many times a Pen is removed from the
                the stand and prints it on LED Matrix display.
*
* Copyright (c) 2017 Aditya K.
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:

* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/


#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>

#include <avr/interrupt.h>
#include <avr/power.h>
#include <avr/sleep.h>



#define PEN_PIN     2
#define MAX_DEVICES 3
#define CLK_PIN     13
#define DATA_PIN    11
#define CS_PIN      10



MD_Parola P = MD_Parola(CS_PIN, MAX_DEVICES);

volatile int pen_count = 1;
volatile bool int_flag = false;
char num[999] = {'\0'};

void deep_sleep() {
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  sleep_enable();
  sleep_mode();
  sleep_cpu();
}

void animate() {
  itoa(pen_count, num, 10);
  P.displayShutdown(false);
  P.print(num);
  delay(350);
  P.displayClear();
  pen_count++;
  P.displayShutdown(true);

  if(pen_count == 999) pen_count = 0;
}

void animation_ISR() {
  sleep_disable();
  int_flag = true;
}

void setup() {

  pinMode(PEN_PIN, INPUT_PULLUP);
  power_usart0_disable();
  power_twi_disable();
  ADCSRA = 0;
  power_adc_disable();
  
  P.begin();
  P.setIntensity(13);
  P.setTextAlignment(PA_CENTER);
  P.displayClear();
  P.displayShutdown(true);

  attachInterrupt(digitalPinToInterrupt(PEN_PIN), animation_ISR, CHANGE);
}

void loop() {
  
  deep_sleep();

  if(int_flag) {
    bool pin_status = digitalRead(PEN_PIN);
    delay(30);
    pin_status = digitalRead(PEN_PIN);

    // Pen is removed
    if(pin_status == HIGH){
       animate();
       int_flag = false;
    }
    // Pen is inserted
    else if(pin_status == LOW){
       int_flag = false;
    }
  }
  attachInterrupt(digitalPinToInterrupt(PEN_PIN), animation_ISR, CHANGE);
  delay(50);
}