Interfacing 16×2 LCD with 8051

In this project, we will have brief discussion on how to interface 16×2 LCD module to AT89C51, which is an 8051 family microcontroller. We use LCD display for the displaying messages in a more interactive way to operate the system or displaying error messages etc. Interfacing 16×2 LCD with 8051 microcontroller is very easy if you understanding the working of LCD.

Hence, in this project, I will not only give the information of LCD and also provide the code in C language which is working fine without any errors.

Also get an idea about Interfacing LEDs with 8051 Mirocontroller

A Brief Note on 16×2 LCD

16×2 Liquid Crystal Display which will display the 32 characters at a time in two rows (16 characters in one row). Each character in the display is of size 5×7 pixel matrix. This matrix differs for different 16×2 LCD modules, if you take JHD162A, this matrix goes to 5×8. There are 16 pins in the LCD module, the pin configuration us given below

PIN NO	NAME	FUNCTION
1	VSS	Ground pin
2	VCC	Power supply pin of 5V
3	VEE	Used for adjusting the contrast commonly attached to the potentiometer.
4	RS	RS is the register select pin used to write display data to the LCD (characters), this pin has to be high when writing the data to the LCD. During the initializing sequence and other commands this pin should low.
5	R/W	Reading and writing data to the LCD for reading the data R/W pin should be high (R/W=1) to write the data to LCD R/W pin should be low (R/W=0)
6	E	Enable pin is for starting or enabling the module. A high to low pulse of about 450ns pulse is given to this pin.
7	DB0
8	DB1
9	DB2
10	DB3
11	DB4	DB0-DB7 Data pins for giving data(normal data like numbers characters or command data) which is meant to be displayed
12	DB5
13	DB6
14	DB7
15	LED+	Back light of the LCD which should be connected to Vcc
16	LED-	Back light of LCD which should be connected to ground.

So by reading the above table you can get a brief idea how to display a character. For displaying a character you should enable the enable pin (pin 6) by giving a pulse of 450ns, after enabling the pin6 you should select the register select pin (pin4) in write mode. To select the register select pin in write mode you have to make this pin high (RS=1), after selecting the register select you have to configure the R/W to write mode that is R/W should be low (R/W=0).

Follow these simple steps for displaying a character or data

• E=1; enable pin should be high
• RS=1; Register select should be high
• R/W=0; Read/Write pin should be low.

To send a command to the LCD just follows these steps:

• E=1; enable pin should be high
• RS=0; Register select should be low
• R/W=0; Read/Write pin should be low.

Commands: There are some preset commands which will do a specific task in the LCD. These commands are very important for displaying data in LCD. The list of commands given below:

Command	Function
0F	For switching on LCD, blinking the cursor.
1	Clearing the screen
2	Return home.
4	Decrement cursor
6	Increment cursor
E	Display on and also cursor on
80	Force cursor to beginning of the first line
C0	Force cursor to beginning of second line
38	Use two lines and 5x7 matrix
83	Cursor line 1 position 3
3C	Activate second line
0C3	Jump to second line position 3
0C1	Jump to second line position1

To get the detailed information, Click Here and Download the Datasheet

Interfacing 16×2 LCD with 8051 Circuit Diagram

Components Required 

• AT89C51 (8051 Microcontroller)
• 16X2 LCD Display
• 11.0592MHz Crystal
• 2 X 33pF Capacitors 
• 2 X 10 KΩ Resistors
• 1 KΩ X 8 Resistor Pack 
• 10 KΩ Potentiometer 
• 330Ω Resistor 
• Push Button 
• 10μF/16V Capacitor 
• 8051 Programmer 
• 5V Power Supply 
• Connecting Wires

Circuit Explanation

The crystal oscillator, along with two 33pF Capacitors, are connected to XTAL1 and XTAL2, which will provide the system clock to the microcontroller. 

RST Pin is pulled-LOW with the help of a 10KΩ Resistor. With the help of a 10μF Capacitor and a Push Button, you can reset the 8051 Microcontroller. EA is pulled-HIGH with the help of a 10KΩ resistor. 

The data pins of the LCD are connected to PORT0 (first, the PORT0 pins must be pulled-HIGH with the help of a 1KΩ Resistor Pack). RS and E are connected to PORT2 pins P2.0 and P2.1.

A 10KΩ Potentiometer is used to adjust the contrast of the LCD. 

Programming LCD to 8051

Coming to the programming you should follow these steps:

• STEP1: Initialization of LCD.
• STEP2: Sending commands to LCD.
• STEP3: Writing the data to LCD.

[Also Read: How To Make an Adjustable Timer ]

Initializing LCD

To initialize LCD to the 8051 the following instruction and commands are to be embed in to the functions

• 0x38 is used for 8-bit data initialization.
• 0xoC for making LCD display on and cursor off.
• 0X01 for clearing the display of the LCD.
• 0x80 for positioning the cursor at first line .

Sending Commands to the LCD

• E=1; enable pin should be high
• RS=0; Register select should be low for sending commands
• Placing the data on the data registers
• R/W=0; Read/Write pin should be low for writing the data.

Writing the Data to the LCD

• E=1; enable pin should be high
• RS=1; Register select should be high for writing data
• Placing the data on the data registers
• R/W=0; Read/Write pin should be low for writing the data.

Important Post – Interfacing 7 Segment Display with 8051 Microcontroller

Code 

Additional Codes 

The programs given below will use above functions and display the complete string which is given by the programmer to display the data. We have provided two demo codes working properly and easy to understand.

Code 1

Code 2

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