Please tell me how many 20X04 with serial interface works in parallel on arduino mega 2560?
I'm very confuse from this line code:
LiquidCrystal_I2C lcd(0x27 20,4); //set the LCD address to 0x27
In order to answer your question we would have to know more about the specific I2C interface chip and its implementation by the designer of the PC board on which the chip is mounted.
Don