16x2 LCD Display Module

16x2 LCD Display Module Pinout Configuration

16×2 LCD is named so because it has 16 Columns and 2 Rows. There are a lot of combinations available, like 8×1, 8×2, 10×2, 16×1, etc. But the most used one is the 16*2 LCD, hence we are using it here. This comprehensive 16x2 LCD display module datasheet guide covers all technical specifications and implementation details.

All the above-mentioned LCD displays will have 16 pins, and the programming approach is also the same; hence, the choice is left to you. Below is the 16x2 LCD display module pinout and pin and  with a detailed 16x2 LCD display module diagram description:

Sr. No	Pin No.	Pin Name	Pin Type	Pin Description	Pin Connection
1	Pin 1	Ground	Source Pin	This is a ground pin of the LCD	Connected to the ground of the MCU/ Power source
2	Pin 2	VCC	Source Pin	This is the supply voltage pin of the LCD	Connected to the supply pin of the Power source
3	Pin 3	V0/VEE	Control Pin	Adjusts the contrast of the LCD.	Connected to a variable POT that can source 0-5V
4	Pin 4	Register Select	Control Pin	Toggles between Command/Data Register	Connected to an MCU pin and gets either 0 or 1. 0 -> Command Mode 1-> Data Mode
5	Pin 5	Read/Write	Control Pin	Toggles the LCD between Read/Write Operation	Connected to an MCU pin and gets either 0 or 1. 0 -> Write Operation 1-> Read Operation
6	Pin 6	Enable	Control Pin	Must be held high to perform the Read/Write Operation	Connected to the MCU and always held high.
7	Pin 7-14	Data Bits (0-7)	Data/Command Pin	Pins are used to send commands or data to the LCD.	In 4-Wire Mode Only 4 pins (0-3) is connected to the MCU In 8-Wire Mode All 8 pins(0-7) are connected to MCU
8	Pin 15	LED Positive	LED Pin	Normal LED like operation to illuminate the LCD	Connected to +5V
9	Pin 16	LED Negative	LED Pin	Normal LED like operation to illuminate the LCD connected with GND.	Connected to ground

Understanding 16x2 LCD Display Module Internal Architecture

It is okay if you do not understand the function of all the pins; I will be explaining in detail below. Now, let us examine the internal components of our 16x2 LCD screen:

Okay, what are these two black circle components on the back of the 16x2 LCD display module?

These black circles consist of an interface IC and its accompanying components to help us work with this 16x2 LCD display with the MCU. This component layout is clearly shown in the 16x2 LCD display module diagram above. Our LCD, a 16*2 Dot matrix LCD, will have (16*2=32) 32 characters in total, where each character will consist of 5*8 Pixel Dots. The picture below shows a Single character with all its pixels enabled.

So now, we know that each character has (5*8=40) 40 Pixels and for 32 Characters we will have (32*40) 1280 Pixels. Further, the 16x2 LCD display module should also be instructed about the Position of the Pixels.

It will be a hectic task to handle everything with the help of the MCU; hence, an Interface IC like HD44780 is used, which is mounted on the LCD Module itself. The function of this IC is to get the Commands and Data from the MCU and process them to display meaningful information on our 16x2 LCD screen.

Let’s discuss the different type of modes and options available in our LCD that has to be controlled by our Control Pins.

16x2 LCD Display Module Specifications

Specification	Value
Display Format	16 characters × 2 lines
Character Matrix	5 × 8 dots
Total Pixels	1280 pixels (32 chars × 40 pixels each)
Controller IC	HD44780U or compatible
Operating Voltage	5V DC
Operating Current	1-3 mA (without backlight)
Backlight Current	120-200 mA
Operating Temperature	0°C to +50°C
Communication Modes	4-bit or 8-bit parallel
Total Pins	16 pins

16x2 LCD Display Module Operating Modes

Next, we will talk about the various operating modes and options associated with our 16x2 LCD display module, which can be controlled by the Control Pins. 

4-bit and 8-bit Mode of LCD:

The LCD can work in two different modes, namely the 4-bit mode and the 8-bit mode. In 4-bit mode, we send the data nibble by nibble, first the upper nibble and then the lower nibble. For those of you who don’t know what a nibble is: a nibble is a group of four bits, so the lower four bits (D0-D3) of a byte form the lower nibble while the upper four bits (D4-D7) of a byte form the higher nibble. This enables us to send 8-bit data.

Whereas in 8-bit mode, we can send the 8-bit data directly in one stroke since we use all 8 data lines.

Now you must have guessed it, yes, 8-bit mode is faster and flawless than 4-bit mode. But the major drawback is that it needs 8 data lines connected to the microcontroller. This will make us run out of I/O pins on our MCU, so 4-bit mode is widely used. No control pins are used to set these modes. It's just the way of programming that changes.

Read and Write Mode of LCD:

As said, the LCD itself consists of an Interface IC. The MCU can either read or write to this interface IC. Most of the time, we will be just writing to the IC, since reading will make it more complex, and such scenarios are very rare. Information like the position of the cursor, status completion interrupts, etc., can be read if required, but it is out of the scope of this tutorial.

The Interface IC present in most of the LCDs is HD44780U. To program our LCD we should learn the complete datasheet of the IC. The 16x2 LCD display module datasheet is given here.

LCD Commands:

There are some preset command instructions in the LCD, which we need to send to the LCD through a microcontroller. Some important command instructions are given below:

Hex Code	Command to LCD Instruction Register
0F	LCD ON, cursor ON
01	Clear display screen
02	Return home
04	Decrement cursor (shift cursor to left)
06	Increment cursor (shift cursor to right)
05	Shift display right
07	Shift display left
0E	Display ON, cursor blinking
80	Force cursor to beginning of first line
C0	Force cursor to beginning of second line
38	2 lines and 5×7 matrix
83	Cursor line 1 position 3
3C	Activate second line
08	Display OFF, cursor OFF
C1	Jump to second line, position 1
OC	Display ON, cursor OFF
C1	Jump to second line, position 1
C2	Jump to second line, position 2

Troubleshooting LCD Display Modules 16x2

Some possible problems with the LCD display modules are identified below, along with suggested solutions.

• Blank display: Check power and connections, and, if applicable, check contrast adjustment on the V0 pin.
• Dim characters: Adjust the contrast potentiometer, reset switch and/or check backlight connections.
• Garbage characters: Check data pin connections and the sequence of initialisation.
• No backlight: Check LED+ and LED- connections, and in some cases, you can add a current-limiting resistor.
• Partial display: Check your Enable pin connection, as well as the timing in your code.

16x2 LCD Display Module FAQ

⇥ How many pins does the 16x2 LCD module have?
The 16x2 LCD module has a total of 16 pins:

• Power pins (2): VCC and Ground
• Control pins (3): Register Select (RS), Enable, and Read/Write
• Data pins (8): D0 to D7 to send commands/data
• Display control (1): V0/VEE to adjust contrast
• Backlight pins (2): LED+ and LED- to provide backlight illumination

⇥ What controller chip is in the 16x2 LCD module?
The vast majority of 16x2 LCD modules use the HD44780U controller IC. This interface chip interfaces the microcontroller to the LCD; it handles the commands and character data so that the 1280 individual pixels can be controlled.

⇥ What is the difference between 4-bit and 8-bit mode?
4-bit: Uses only 4 of D4-D7, sends data nibble by nibble, conserves microcontroller pins.
8-bit: Uses all D0-D7, sends a complete byte at once, faster, consumes more pins.

Check our LCD interfacing Articles with different Microcontrollers:

• LCD Interfacing with 8051 Microcontroller
• Interfacing LCD with ATmega32 Microcontroller
• LCD Interfacing with PIC Microcontroller
• Interfacing a 16x2 LCD with Arduino
• 16x2 LCD Interfacing with Raspberry Pi using Python

Dive into LCD Interfacing Projects

Create a deeper understanding of 16x2 LCD modules by diving into these diverse microcontroller-based interfacing projects.