As our project can be used with different hardware parts.
So I want to use preprocessor directives like:
#define USE_I2C_LCD
#if ENABLED(USE_I2C_LCD)
#include <LiquidCrystal_I2C.h> //https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads/NewliquidCrystal_1.3.4.zip
//LiquidCrystal_I2C lcd(0x27); // Set the LCD I2C address
// addr, en,rw,rs,d4,d5,d6,d7,bl,blpol
//LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); //PCF8574
LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); //PCF8574A
#endif
So what could be wrong??