Interfacing 16*2 LCD With 8051 Microcontroller

What Is  16*2 LCD ?

The LCD ( liquid crystal display) is device to good communicate between user and machine. It display the Software status, Errors, Indicators, Data as per user program by which a good Control method and a good communication occurs between user and electronics system and make a more user Friendly and attractive.

16*2 LCD Display

Features:

Lcd displays are widely used because of its low current consumption as compared to seven segment displays. And another, it is more attractive to the seven segment display (SSD).

16*2 LCD is mostly used to interfacing of 8051 Microcontroller.

 How 16*2 LCD Interface With 8051 Microcontroller ?

Pin Description and  Details of 16*2 LCD

 Applications:

1. Digital Voltmeter / Ammeter.
2. Digital Speedometer / odometer.
3. Home Automation System.
4. Display for Music Player.
5. Status Indicator Display.
6. Digital Clock. 

Command to Operate 16*2 LCD Display Module:

      
            Hex Code                            Work Function
               38h         -        Initialize 2 line display of 5*7 Matrix.
               01h         -        Clear Display
               02h         -        Cursor Return to Home        
               04h         -        Decrement Cursor ( in Left Side )
               05h         -        Shift Display Right
               06h         -        Increment Cursor ( in Right Side )
               07h         -        Shift Display Left Side
               08h         -        Display Off & Cursor Off
               0ah         -        Display Off & Cursor On
               0ch         -        Display On & Cursor Off
               0eh         -        Display On & Cursor On
               0fh          -        Display On & Cursor On and Blinking
               10h         -        Move Cursor One Position Left Side
               14h         -        Move to Cursor One Position Right Side
               18h         -        Shift Entire Display Left Side
               1ch         -        Shift Entire Display Right Side
               80h         -        Move Cursor to Beginning of 1st Line
               c0h                  Move Cursor to Beginning of 2nd Line

How 16*2 LCD Display Work? How We can Display Message on 16*2 LCD? How to Initialization of 16*2 LCD? LCD Initialization........

1. Give the Supply and Wait for a Second to Stabilize the Display.
2. Give the Instruction 38h for Initialize 2 Line display of 5*7 Matrix LCD.
3. Wait for a few millisecond (approx 5ms) to Complete Operation and LCD take Action as per given Command.
4. Give 0fh Command to Display ON & Cursor ON and Blinking.
5. Wait for some time (approx 5 ms).
6. Give command 01h to clear the Display of LCD.
7. Wait for some time (approx 5ms).
8. Give command 06h for making Increment Cursor mode of LCD. By this, cursor should increase after every Character is Written to display automatically.
9. Wait for some time (approx 5 ms).   
10. Give the command 80h for Cursor take position at 1st Line 1st Character.

This above 10 step is Require and Basic Common Instruction for 16*2 LCD Initialization. Thus it write to start up of every Program Related to the LCD Projects. Then the User can Program to display the Data or Information on LCD as per requirement of User. This is Explain with a Short Program example of to Display the "Welcome to Here" on the LCD Display.

Circuit Diagram: 

 

Circuit diagram of LCD interfacing with 8051 Microcontroller

Assembly Language  Program to Display "Welcome to Here" in 16*2 LCD Display:

org 0000h

port_ini:

mov p1,#00h

setb p3.4

setb p3.5

setb p3.6

acall delay_1s

Lcd_ini:

mov a,#38h

acall command

mov a,#06h

acall command

mov a,#0ch

acall command

mov a,#01h

acall command

mov a,#80h

acall command

acall delay_1s

Display:

mov a,#'W'

acall write

mov a,#'e'

acall write

mov a,#'l'

acall write

mov a,#'c'

acall write

mov a,#'o'

acall write

mov a,#'m'

acall write

mov a,#'e'

acall write

mov a,#14h

acall command

mov a,#'t'

acall write

mov a,#'o'

acall write

mov a,#14h

acall command

mov a,#'H'

acall write

mov a,#'e'

acall write

mov a,#'r'

acall write

mov a,#'e'

acall write

here:

sjmp here

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

command:

mov p1,a

clr p3.4

clr p3.5

setb p3.6

acall delay

clr p3.6

acall delay

acall delay

ret

write:

lcall ready

mov p1,a

setb p3.4

clr p3.5

setb p3.6

acall delay

clr p3.6

acall delay

acall delay

ret

ready:

setb p1.7

clr p3.4

setb p3.5

wait:

clr p3.6

acall delay

setb p3.6

jb p1.7,wait

ret

delay:

mov r0,#1ch

rep:

djnz r0,rep

ret

delay_1s:

mov r3,#08h

df1s:

mov r2,#0ffh

d1s:

mov r1,#0ffh

de1s:

djnz r1,de1s

djnz r2,d1s

djnz r3,df1s

ret

end