PC CONTROLLED SCROLLING MESSAGE DISPLAY FOR COLLEGE NOTICE BOARD Project Title PC CONTROLLED SCROLLING MESSAGE DISPLAY FOR COLLEGE NOTICE BOARD Under the Guidance of Submitted by

ABSTRACT This project is designed to develop a PC controlled scrolling message display for college notice board. It can also be used to display latest information anywhere such as faculty, shop, mosque and other places. The information is transmitted using PC. The PC is interfaced to microcontroller through MAX232 IC. An external memory is used to store the information. The information sent through PC is display on a LCD interfaced with the microcontroller. This project is based on microcontroller from 8051 family. Embedded C language is used to program this microcontroller.

BLOCK DIAGRAM

HARDWARE REQUIREMENTS TRANSFORMER (230 – 12 V AC) VOLTAGE REGULATOR (LM 7805) RECTIFIER FILTER MICROCONTROLLER (AT89S52/AT89C51) PUSH BUTTONS MAX232 DB9 CONNECTOR EEPROM IC PC LCD IN4007 LED RESISTORS CAPACITORS

POWER SUPPLY Bridge rectifier 5v Regulator 230 V AC 50 Hz 5V DC Filter(470µf) 12V step down transformer

It is a smaller computer Has on-chip RAM, ROM, I/O ports... MICROCONTROLLER It is a smaller computer Has on-chip RAM, ROM, I/O ports... RAM ROM I/O Port Timer Serial COM Port Microcontroller CPU A single chip

INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S52/51 CPU On-chip RAM On-chip ROM for program code 4 I/O Ports Timer 0 Serial Port OSC Interrupt Control External interrupts Timer 1 Timer/Counter Bus Control TxD RxD P0 P1 P2 P3 Address/Data Counter Inputs

Features of AT89S51/52 Compatible with MCS®-51 Products 8K Bytes of In-System Programmable (ISP) Flash Memory Endurance: 10,000 Write/Erase Cycles 4.0V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHz 256 x 8-bit Internal RAM 32 Programmable I/O Lines Three 16-bit Timer/Counters Eight Interrupt Sources Full Duplex UART Serial Channel Interrupt Recovery from Power-down Mode Watchdog Timer Dual Data Pointer

Pin Description

MAX 232 The MAX232 is an integrated circuit that converts signals from an RS-232serial port to signals suitable for use in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals . When a MAX232 IC receives a TTL level to convert, it changes a TTL Logic 0 to between +3 and +15V, and changes TTL Logic 1 to between -3 to -15V, and vice versa for converting from RS232 to TTL.

DB9 CONNECTOR The DB9 (originally DE-9) connector is an analog 9-pin plug of the D-Sub miniature connector family (D-Sub or Sub-D). DB 9 PIN CONNECTOR

EEPROM IC

LED LEDs are semiconductor devices are made out of silicon.When current passes through the LED, it emits photons as a byproduct. Normal light bulbs produce light by heating a metal filament until its white hot. LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching

LIQUID CRYSTAL DISPLAY (LCD) Most common LCDs connected to the microcontrollers are 16x2 and 20x2 displays. This means 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively. The standard is referred to as HD44780U, which refers to the controller chip which receives data from an external source (and communicates directly with the LCD.

LCD BACKGROUND If an 8-bit data bus is used the LCD will require 11 data lines (3 control lines plus the 8 lines for the data bus) The three control lines are referred to as EN, RS, and RW EN=Enable (used to tell the LCD that you are sending it data) RS=Register Select (When RS is low (0), data is treated as a command) (When RS is High(1), data being sent is text data ) R/W=Read/Write (When RW is low (0), the data written to the LCD) (When RW is High(1), the data reading to the LCD)

Working of project This project is designed to develop a PC controlled scrolling message display for college notice board. It can also be used to display latest information anywhere such as shop, mosque and other places. The information is transmitted using PC. The PC is interfaced to microcontroller through MAX232 IC. An external memory is used to store the information. The information sent through PC is display on a LCD interfaced with the microcontroller.

Soft ware Requirements Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families. Compilers are programs used to convert a High Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors.

i.e the programs written in one of the HLL like ‘C’ will compile the code to run on the system for a particular processor like x86 (underlying microprocessor in the computer). For example compilers for Dos platform is different from the Compilers for Unix platform  So if one wants to define a compiler then compiler is a program that translates source code into object code.

BIBILOGRAPHY “The 8051 Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice Gillispie Mazidi , Pearson Education. ATMEL 89S52 Data Sheets. www.atmel.com www.beyondlogic.org www.wikipedia.org www.howstuffworks.com www.alldatasheets.com

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