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PREFACE
This report is all about the embedded systems and its applicationsin various fields of real world. We are living in the Embedded World. We are surrounded with many embedded products and our daily life largely depends on proper functioning of these gadgets. Television, Radio, CD player, WashingMachine or Microwave Oven in our kitchen, Card readers, Access Controllers,Palm devices of our space enable us to do many of our tasks very effectivelyApart from all these , many controllers embedded in our car take care of car operations between the bumpers. All kinds of magazines and journalsregularly dish out details about latest technologies, new devices; applicationswhich make us believe that our basic survival is controlled by these embeddedproducts. Now we can agree to the fact that these embedded products havesuccessfully invaded into our vast world. What is this Embedded System?Theoretically an embedded controller is combination of piece of microprocessorbased hardware and the suitable software to undertake a specific task.
INTRODUCTION TO EMBEDDED SYSTEMS
Microcontrollers are widely used in Embedded System products. An Embedded product uses the microprocessor (or microcontroller) to do one task & one task only. A printer is an example of embedded system since the processor inside it performs one task only namely getting the data and printing it. Contrast this with Pentium based PC. A PC can be used for any no. of applications such as word processor, print server, bank teller terminal, video game player, network server or internet terminal. Software for variety of applications can be loaded and run. Of course the reason a PC can perform multiple tasks is that it has RAM memory and an operating system that loads the application software into RAM & lets the CPU run it. In and Embedded system there is only one application software that is typically burn into ROM. An x86PC Contain or its connected to various Embedded Products such as keyboard, printer, modem, Disc controller, Sound card, CD-ROM Driver, Mouse & so on. Each one of these peripherals as a microcontroller inside it that performs only one task. For example inside every mouse there is microcontroller to perform the task of finding the mouse position and sending it to PC.
EMBEDDED SYSTEM
An Embedded System employs a combination of hardware & software (a “computational engine”) to perform a specific function; is part of a larger system that may not be a “computer works in a reactive and time-constrained environment. Software is used for providing features and flexibility Hardware = {Processors, ASICs, Memory...} is used for performance (& sometimes security
An embedded system is a special purpose system in which the computer is completely encapsulated by the device it controls. Unlike a general purpose computer, such as a PC, an embedded system performs predefined task’s usually with very specific tasks design engineers can optimize it reducing the size and cost of the product. Embedded systems are often mass produced, so the cost savings may be multiplied by millions of items.
The core of any embedded system is formed by one or several microprocessor or micro controller programmed to perform a small number of tasks. In contrast to a general purpose computer, which can run any software application, the user chooses, the software on an embedded system is semi-permanent, so it is often called firmware.
APPLICATIONS OF EMBEDDED SYSTEM
Automated tiller machines (ATMS).
Avionic, such as inertial guidance systems, flight control hardware / software and letter integrated system in aircraft and missile.
Cellular telephones and telephonic switches.
Computer network equipment, including routers timeservers and firewalls
Computer printers, Copiers.
Disk drives (floppy disk drive and hard disk drive)
Engine controllers and antilock brake controllers for automobiles.
Home automation products like thermostat, air conditioners sprinkles and security monitoring system.
House hold appliances including microwave ovens, washing machines, TV sets DVD players/recorders.
Medical equipment.
Measurement equipment such as digital storage oscilloscopes, logic analyzers and spectrum analyzers.
Multimedia appliances: internet radio receivers, TV set top boxes.
Personal digital assistants (PDA’s), i.e., small hand held computer with P1M5 and other applications.
Programmable logic controllers (PLC’s) for industrial automation and monitoring.
Stationary video game controllers.
Wearable computers.
ASPECTS OF AN EMBEDDED SYSTEM
• Real time operations
• Time
• Size
• Cost
• Reliability
• Safety
• Energy
• Security
BUILDING BLOCKS OF EMBEDDED SYSTEM
The basic building blocks of embedded system are-:
1. Input/Sensors
2. Processors
3. Output/Actuators
PROCESSORS-: A Processor executes all the functions of a system.
A Processor is the heart of embedded system.
It has two units- (a.) Control Unit
(b.) Execution Unit
INPUT AND OUTPUT DEVICES -: The input systems are used to provide the input to any system. Some of the input devices are Sensors, Keypad, Camera, Bluetooth, etc.
The output device gives output to the user. Some of the output devices are LED, LCD, Speaker, Buzzer, etc.
PROCESSORS -: Processor technology involves the architecture of the computation engine used to implement a system’s desired functionality. Some of the microcontrollers are given below-:
1. 8051
2. ATmega8
3. ATmega16
4. PIC (Peripheral Interface Controller)
5. ARM (Advanced RISC Machines), etc.
8051 Microcontroller Memory Organization
The microcontroller memory is divided into Program Memory and Data Memory. Program Memory (ROM) is used for permanent saving program being executed, while Data Memory (RAM) is used for temporarily storing and keeping intermediate results and variables. Depending on the model in use ( still referring to the whole 8051 microcontroller family) at most a few Kb of ROM and 128 or 256 bytes of RAM can be used.
All 8051 microcontrollers have 16-bit addressing bus and can address 64 kb memory. It is neither a mistake nor a big ambition of engineers who were working on basic core development. It is a matter of very clever memory organization which makes these controllers a real “programmers’ tidbit“.
Different types of micro-controllers are used in the embedded system. Some of them are given below-:
• 8051
• Atmega8
• Atmega16
• PIC
• ARM