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

#define I2C_ADDR    0x27
#define LCD_COLUMNS 16
#define LCD_LINES   2

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(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

int cursorPosition = 0;
int lcdLineNo = 0;

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
}

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

  if (key != NO_KEY) {
    Serial.print(key);Serial.print("-");Serial.print(cursorPosition);Serial.print(",");Serial.print(lcdLineNo);
    lcd.setCursor(cursorPosition, lcdLineNo);
    lcd.print(key);
    cursorPosition += 1;
    if ((cursorPosition >= 16) && (lcdLineNo == 0)) {
      cursorPosition = 0;
      lcdLineNo += 1;
    } else if ((cursorPosition >= 16) && (lcdLineNo == 1)) {
      cursorPosition = 0;
      lcdLineNo = 0; 
      lcd.clear();
    }
  }
}