moving msg display

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Moving Message Display using 8051 and 16X2 LCD

Introduction

LCD-based moving-message displays are becoming popular for transmitting information to large

groups of people quickly. These can be used indoors or outdoors. We can find such displays inareas like railway platforms, banks, public offices, hotels, training institutes, nightclubs andshops.

The objective of the projects is to provide non-commercial and purely academic insight into

microcontroller assembly programming. The over all goal of the projects is to provideconnectivity between microcontroller and a HD44780 compatible LCD.

The LCD comes with a 14pin interface, which includes pins to receive power supply and ground

as well. These 14pins have to be interfaced with microcontroller output ports to send

instructions, which initialize the LCD in appropriate modes, and also to send data from themicrocontroller is intended for display on the LCD output screen.

A string or message can be displayed on LCD by sending its characters to data register after

configuring the command register of LCD. To create dynamic effects, a specific commandinstruction is sent to LCD via microcontroller AT89C51.

Moving message on LCD are ideal for all type of commercial establishments like Hotels,

Restaurants, Retail Shops Banks, Airports, Clinics, Hospitals and other such places to get

maximum attention of people. These displays attract customers to watch the display withcuriosity and your scrolling message also is conveyed simultaneously.

Hardware Aspects of Moving Message Display Project:-

The moving message display is fabricated using these major components:-

1. Micro controller AT89s51

2. LCD3. RS-232

4. Computer

the moving message will be display on the LCD which will be controlled throughmicrocontroller and the message will be sent by computer using RS232. The circuit diagram of

the moving message display is shown in this post and how the whole process is completed is

discussed here.The Microcontroller in this software is programmed such that it controls the LCD through an

interface. An eight-bit interface between in the LCD and Microcontroller is programmed to

transfer the data to be written on the LCD display screen. A further three out pins of the

Microcontroller are used to generate control signals for the LCD. The three control signals aregenerated in the same pattern as discussed in the timing diagram in the previous chapters.

The project, when looked in totality, can be seen as composing of three components, namely

LCD, Microcontroller and serial port. The three components have been discussed independently

until now and to give a complete picture, it is necessary to link these components. The linking is notonly logical but is also translated into hardware connections.

Introduction to 8051

A BRIEF INTRODUCTION TO 8051 MICROCONTROLLER


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When we have to learn about a new computer we have to familiarize about the machine

capability we are using, and we can do it by studying the internal hardware design (devices

architecture), and also to know about the size, number and the size of the registers.

A microcontroller is a single chip that contains the processor (the CPU), non-volatile memory for

the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O

control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs) areembedded each year in a myriad of products from toys to appliances to automobiles. For

example, a single vehicle can use 70 or more microcontrollers. The following picture describes a

general block diagram of microcontroller.89s52: The AT89S52 is a low-power, high-

performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash

memory. The device is manufactured using Atmels high-density nonvolatile memory

technology and is compatible with the industry-standard 80C51 instruction set and pinout. The

on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional

nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system

programmable Flash on a monolithic chip, the Atmel's AT89S52 is a powerful microcontroller

which provides a highly-flexible and cost-effective solution to many embedded control

applications. The AT89S52 provides the following standard features: 8K bytes of Flash, 256bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a

six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock

circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode stops the

CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue

functioning. The Power-down mode saves the RAM con-tents but freezes the oscillator,

disabling all other chip functions until the next interrupt.The hardware is driven by a set of

program instructions, or software. Once familiar withhardware and software, the user can then

apply the microcontroller to the problems easily.

Introduction to 16 X2 LCD

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of

applications. A 16x2 LCDdisplay is very basic module and is very commonly used in various

devices and circuits. These modules are preferred over seven segments and other multi segment

LEDs. The reasons being: LCDs are economical; easily programmable; have no limitation of

displaying special & even custom characters (unlike in seven segments), animations and so on.

A 16x2 LCD means it can display 16 characters per line and there are 2 such lines. In this LCD

each character is displayed in 5x7 pixel matrix. This LCD has two registers, namely, Command

and Data.The command register stores the command instructions given to the LCD. A commandis an instruction given to LCD to do a predefined task like initializing it, clearing its screen,

setting the cursor position, controlling display etc. The data register stores the data to be

displayed o

n the LCD. The data is the ASCII value of the character to be displayed on the LCD.


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Circuit diagram:

Tools Used

Software tools

Keil C compiler

8051 burner

Hardware tools

Soldering iron


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Soldering flux

Solder

Multi-meter

Wires

Hardware to be used:

PCB

8051 controller

10uf

LCD 16*2

33pf

Crystal 11.059 mhz

Resistances: 10k

moving msg display

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