#include <LCD_I2C.h>
#include <Wire.h>
#include <I2CKeyPad.h>
LCD_I2C lcd(0x3C, 16, 2); //incorporate LCD
I2CKeyPad keyPad(0x38);   //incorporate Keypad
uint32_t start, stop;
uint32_t lastKeyPressed = 0;

void setup(){
  Serial.begin(115200);  Serial.println();  Serial.println(__FILE__);  
  Serial.print("I2C_KEYPAD_LIB_VERSION: ");  Serial.println(I2C_KEYPAD_LIB_VERSION);  Serial.println();
  Wire.begin();
  Wire.setClock(400000);
  if (keyPad.begin() == false)  {
    Serial.println("\nERROR: cannot communicate to keypad.\nPlease reboot.\n");
    while (1);
  }
}

void loop(){
  uint32_t now = millis();
  char keys[] = "123A456B789C*0#DNF";  //  N = NoKey, F = Fail
  if (now - lastKeyPressed >= 100)  {
    lastKeyPressed = now;
    start = micros();
    uint8_t index = keyPad.getKey();
    stop = micros();
    Serial.print(millis()); Serial.print("\t"); Serial.print(index); Serial.print("\t"); 
    Serial.print(keys[index]); Serial.print("\t"); Serial.println(stop - start);
  }
}