post details Interface-LCD-HITACHI 44780 | Interfacing-8051-Microcontrollers-89C51-89C52-89S51-89S52 | AT89C51-AT89C52-AT89S51-AT89S52-LCD-Interfacing-Microcontrollers
Interfacing LCD 89C51, 89C52, 89S51, 89s52microcontrollers
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Interfacing 16x1 LCD, 16x2 LCD, 16x4 LCD, 20x1 LCD, 20x2 LCD, 20x3 LCD, 20x4 LCD 8051 Microcontroller Family Models :
 
Atmel, NXP, Philips, 8051, 8052, 89C51, 89C52, 89S51, 89s52, 89C1051, 89C1051, 89C2051, AT89C4051, AT89S8252,l AT89C1051, AT89C2051, AT89C4051, P89C51RB+, P89C51RC+, P89C51RD+, P89C51RB2Hxx, P89C51RC2Hxx, P89C51RD2Hxx, P89C660, P89C662, P89C664, P89C668, P89C669, P89C51RA2xx, P89C51RB2xx, P89C51RC2xx, P89C51RD2xx, P89C60X2, P89C61X2,P89LV51RB2, P89LV51RC2, P89LV51RD2, P89V51RB2, P89V51RC2, P89V51RD2, P89V660, P89V662, P89V664.
 
 About LCD (Liquid Crystal Display) : Overview And Tutorials
Interfacing LCD is the important part of the website and must visited area. Here we will explore how to use simple LCD display using 8051 Microcontrollers and display message on LCD display screen. LCD (liquid crystal display) is the most common and widely used component in our every day's Life. They can be seen all around us as in our laptop computers, digital clocks and watches, microwave ovens, CD players and many other electronic and embedded devices. They are small in sizes and lighter and consume less power than cathode ray tubes (CRTs) or computer monitors, LCDs are suitable if you want simple information to show. Electronic watches, microwaves, temperature displays, timers fall into the same category. Liquid Crystal Display is very helpful in giving user interface to the user of the product. Different standards and versions of LCDs are available in the market example :
 
Some Common and different versions and Models Of LCD Displays
 
16x1 LCD with Green/Blue Backlight
16x2 LCD with Green/Blue Backlight
16x4 LCD with Green/Blue Backlight
20x1 LCD with Green/Blue Backlight
20x2 LCD with Green/Blue Backlight
20x4 LCD with Green/Blue Backlight
 
These are the most common LCDs connected to the 8051 are 16x2 and displays. This means 16 characters per line by 2 lines and 20 characters per line by 2 line. From function and working point of view all these LCDs are same. To interface the LCD with the 8051 Microcontrollers first we have to understand how they work. These LCD's are easy to understand and simple to connect with the 8051 Microcontrollers also they are very cost effective. It has different models the most common models are 2x16 Line Alphanumeric LCD Display, the most commonly used ALPHANUMERIC displays are 1x16 Single Line & 16 characters, 2x16 Double Line & 16 character per line & 4x20 Four lines & Twenty characters per line.
 
Some Basic LCD Commands 
The 8051 Microcontrollers are capable of interacting with the outside world using its input and output pins. The most common and widely devices connected to 8051 Microcontrollers is LCD display. The most common and widely used type of LCD controller is HITACHI 44780 which provides a very simple and easy to use interface between the 8051 Microcontrollers. So the HITACHI 44780 has become standard for every LCD controller. Basically it referred to as HITACHI 44780, which refers to the controller chip which is 
connected with the 8051 Microcontrollers and get and send data. 
 
A common version of LCD requires 3 control lines to send and receive commands (RS, R/W & EN). 8 or 4 data lines to send the commands and showing data. If LCD is operated in 8-bit mode which is the common and easily adopted method then 8 data lines + 3 control lines total 11 lines or points are required to control the LCD Screen. If LCD operated in 4-bit mode then 4 data lines + 3 control lines 7 lines are required.
 
How to decide which method is the best. I tell you If you have sufficient time and adequate pins on the 8051 Microcontrollers to connect LCD use 8 Bit mode connection. If here are the scarcity of the time and lack of adequate pins then 4 Bit mode is right decision to connect the LCD and one thing most important here 8 Bit mode is faster then 4 Bit mode.
 
When we set RS to low (0) then sending data is to be referred as a command send to the LCD. When we set RS to high (1) state, then sending data is considered as text data means the message that you want to display on the LCD Screen.
 
When R/W line if LCD is low (0) then the data is being written on the LCD screen and displayed when command is complete. When RW line is high (1), the software in the microcontroller called embedded software is reading the contents of the LCD Generally it is not common to read anything from the LCD.
 
The ENABLE pin functions to to latch the data present on the data pins at LCD. A HIGH - LOW signals are required to latch the data on LCD.