LCD pin descriptions

Vcc, Vss, Vee:



While Vcc and Vss provide +5V and ground respectively, Vee is used for controlling LCD contrast.



RS, register select:

There are two very important registers inside LCD. The RS pin is used for their selection as follows. If RS =0, the instruction command code register is selected, allowing the user to send a command such as clear display, cursor at home, etc. If RS=1, the data register is selected, allowing the user to send data to be displayed on the LCD.



R/W, read/write:

R/W input allows the user to write information to the LCD or read information from it. R/W=1 when reading; R/W=0 when writing.



E,enable:

The enable pin is used by the LCD to latch information presented to its data pins. When data is supplied to data pins, a high-to-low pulse must be applied to this pin in order for the LCD to latch in the data present at the data pins. This pulse must be a minimum of 450 ns wide.



D0-D7:

The 8-bit data pins, D0-D7, are used to send information to the LCD or read the contents of the LCD’s internal registers.

To display letters and numbers, we send ASCII codes for the letters A-Z, a-z and numbers 0-9 to these pins while making RS=1.

These are also instructions command codes that can be sent to the LCD to clear the display or force the cursor to the home position or blink the cursor.