R/W pin 0 mean write data or control to LCD and R/W pin 1 means read data from the LCD. To send a data to LCD, make RS high, R/W low, place the data in pins 7 to 14 and make pin E high and low once. To make this let us first build a circuit. We are going to write on the LCD module and not reading back. So, R/W is connected to ground directly.