Product Review

Introduction
LCD2004 display is a dot matrix module designed to display 20 characters including letter, number, and symbol, supporting 4-bit and 8-bit data transmission mode. It's quite convenient for beginners to call the built-in library Liquid Crystal of Arduino IDE, no need to edit yourself.
Working voltage: 5V; Contrast adjustable with a 50K potentiometer onside. To use the 3.3V backlight, just connect pin A to 3.3V, pin K to GND.
Note: Solder the pin headers on it before using.
Pins' Function
VSS: Connected to ground
VDD: Connected to a +5V power supply
VO: To adjust the contrast
RS: A register select pin that controls where in the LCD's memory you are writing data to. You can select either the data register, which holds what goes on the screen, or an instruction register, which is where the LCD's controller looks for instructions on what to do next.
R/W: A Read/Write pin to select between reading and writing mode
E: An enabling pin that, when low-level energy is supplied, causes the LDC module to execute relevant instructions.
D0-D7: To read and write data
A and K: Pins that control the LCD backlight
For more details, please click: http://wiki.sunfounder.cc/index.php?title=LCD2004_Module

Package Included
-1 x LCD2004
-16 x Pin Headers