PRE-PROGRAMMED DIGITAL SCROLLING MESSAGE Under the guidance of

PRE-PROGRAMMED DIGITAL SCROLLING MESSAGE Under the guidance of submitted by

CONTENTS PROJECT OVERVIEW BLOCK DIAGRAM MICROCONTROLLER 8052 ALPHA NUMERIC KEYS 74 LS 138 BC 557 SCHEMATIC & WORKING OF THE PROJECTS ADVANTAGES APPLICATIONS FUTURE SCOPE CONCLUSION

PROJECT OVERVIEW A DC voltage of 5 V is drawn from power supply voltage regulator is fed to micro controller. Here the circuit uses 16 segment alpha numeric displays to show 16 characters at a time. More over, programming has been done in micro controller to make the characters move in a beautiful manner. It displays 16 different messages to depict different occasions, which can be selected by the user through a DIP Switch. Using of Alphanumeric displays for above purpose, programming burden is reduced and becomes highly cost effective. This circuit is mainly used in areas like railway platforms, banks, hotels, nightclubs etc

BLOCK DIAGRAM

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

FEATURES OF MC 8052 8 K Bytes of In-System Programmable (ISP) Flash Memory 4. 0 V to 5. 5 V 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

BLOCK DIAGRAM OF MC External interrupts Interrup t Control On-chip ROM for program code Timer/Counter On-chip RAM Timer 1 Timer 0 CPU OSC Bus Control 4 I/O Ports P 0 P 1 P 2 P 3 Address/Data Serial Port Tx. D Rx. D Counter Inputs

PIN OUT OF 8052

POWER ON RESET CIRCUIT +5 V + 10 u. F 31 30 p. F 8. 2 K 30 p. F 11. 0592 MHz 19 18 EA/VPP X 1 X 2 9 RST

74 LS 138 (3 -TO-8 DECODER/DEMULTIPLEXER) • The 74 LS 138 are high-speed CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). • The 74 LS 138 decoders accept three binary weighted address inputs (A, B and C) and when enabled, provide 8 mutually exclusive active LOW outputs (Y 0 to Y 7). • This multiple enable function allows easy parallel expansion of the ‘ 138’ to a 1 -of-32 (5 to 32 lines) decoder with just four ‘ 138’ ICs and one inverter. • The ‘ 138’ features three enable inputs: two active LOW (G 2 A and G 2 B) and one active HIGH (GL). Every output will be HIGH unless G 2 A and G 2 B are LOW and GL is HIGH.

Features ØDesigned specifically for high speed: Memory decoders Data transmission systems Ø 74 LS 138 3 -to-8 -line decoders incorporates 3 enable inputs to simplify cascading and/or data reception ØDM 74 LS 139 contains two fully independent 2 -4 line decoder/mulitiplexere lamped for high perform • Typical propagation delay (3 levels of logic) 74 LS 138 21 ns 74 LS 139 21 ns • Typical power dissipation 74 LS 138 32 m. W 74 LS 139 34 m. W Connection Diagrams

Function Tables

Alpha Numeric Display ØAlphanumeric displays are designed for numeric indication on instruments, meters, home appliance, communication, computing equipment, and display panels. display available with different character heights

Internal structure of a alpha numeric key Connections of an Alpha Numeric Led display

BC 557 (PNP TRANSISTOR) ØThe BC 557 transistor is an PNP Epitaxial Silicon Transistor ØThe BC 557 transistor is a general-purpose transistor in small plastic packages. Ø It is used in general-purpose switching and amplification BC 847/BC 547 series 45 V, 100 m. A PNP general-purpose transistors

ØThe arrow in the PNP transistor symbol is on the emitter leg and points in the direction of the conventional current flow when the device is in forward active mode.

SOFTWARE REQUIREMENTS Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM 7/ARM 9/Cortex-M 3, XC 16 x/ST 10, 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.

CONTD. . 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 x 86 (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.