#include <LiquidCrystal_I2C.h>
#include <Wire.h>

const byte Btn1 = 2;
const byte Btn2 = 3;
const byte LED1 = 4;
const byte Bzr1 = 5;
const byte POT_1 = A0;
volatile bool ISR11 = false;
volatile bool ISR12 = false;
const float Reference_Voltage = 5.0;
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows

void setup() {
  // put your setup code here, to run once:
  lcd.init(); // initialize the lcd
  lcd.backlight();
  pinMode(LED1, OUTPUT);
  pinMode(Bzr1, OUTPUT);
  pinMode (Btn1, INPUT_PULLUP);
  pinMode(Btn2, INPUT_PULLUP);
   // Enable PCIE2 Bit3 = 1 (Port D)
  PCICR |= B00000100;
  // Enable PCINT18  & PCINT19 (Pins D2 & D3)
  PCMSK2 |= B00001100;
}

void loop() {
  //check intterupt 1 
  if(ISR11){
  digitalWrite(LED1, HIGH);
  lcd.clear();                 // clear display
  lcd.setCursor(2, 0);         // move cursor to   (2, 0)
  lcd.print("LED ISR1 ON");        // print message at (2, 0)
  lcd.setCursor(2, 1);         // move cursor to   (2, 1)
  lcd.print("8 Seconds"); // print message at (2, 1)
  delay(8000);                 // display the above for two second
  digitalWrite(LED1, LOW);
  ISR11 = false;
  }

  //check intterupt 2
  if(ISR12){
  digitalWrite(Bzr1, HIGH);
  lcd.clear();                 // clear display
  lcd.setCursor(2, 0);         // move cursor to   (2, 0)
  lcd.print("BUZZER ISR2 ON");        // print message at (2, 0)
  lcd.setCursor(2, 1);         // move cursor to   (2, 1)
  lcd.print("7 Seconds"); // print message at (2, 1)
  delay(7000);                 // display the above for two second
  digitalWrite(Bzr1, LOW);
  ISR12 = false;
  }
  // put your main code here, to run repeatedly:
  POT1();
}

void POT1(){
int analog_value = analogRead(POT_1);
float voltage = (analog_value * Reference_Voltage/1023);
// maximun value is 2.5 V
//float voltage = map(analog_value, 0, 1023, 0 , 5);
char analog_string[7];
dtostrf(voltage, 5, 3, analog_string); 
  lcd.clear();                 // clear display
  lcd.setCursor(0, 0);         // move cursor to   (0, 0)
  lcd.print("VOLTS:");        // print message at (0, 0)
  lcd.print(analog_string);
  lcd.print(" V");
  lcd.setCursor(0, 1);         // move cursor to   (0, 1)
  lcd.print("DOUT ");
  lcd.print(analog_value);
  delay(100); 
}

ISR (PCINT2_vect)
{
  // Port D Interrupt occured
if (digitalRead(Btn1) == LOW) {
ISR11 = true;
}

if (digitalRead(Btn2) == LOW) {
ISR12 = true;
}
}