#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
#include <TimerOne.h>


const uint8_t ROWS = 4;
const uint8_t COLS = 3;
char keys[ROWS][COLS] = {
  { '1', '2', '3'},
  { '4', '5', '6' },
  { '7', '8', '9' },
  { '*', '0', '#' }
};

uint8_t colPins[COLS] = { 5, 4, 3, }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; // Pins connected to R1, R2, R3, R4

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
LiquidCrystal_I2C lcd(0x27,20,4);

int sec=0;
bool _update=false;
void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  Timer1.initialize(1000000);
  Timer1.attachInterrupt(clock);

}

void loop() {
  char key = keypad.getKey();

  if (key != NO_KEY) {
    lcd.setCursor(0,0);
    lcd.print(key);
  }
  if(_update)
  {
    lcd.setCursor(0,2);
    lcd.print(sec);
    lcd.print(" ");
    _update=false;
  }
}

void clock(){
  if(sec<59)
    sec++;
  else
    sec=0;
  _update=true;
}