Paper Presentation On 'Embedded Systems'

ABSTRACT:

A general-purpose definition of embedded systems is that they are devices used to control, monitor or assist the operation of equipment, machinery or plant. “Embedded” reflects the fact that they are an integral part of the system. In many cases, their “embeddedness” may be such that their presence is far from obvious to the casual observer.
Imagine you control all the systems around just by a simple gesture and the things respond to you as if it was some magic. This could be possible with embedded system. An embedded system can be consisting of processors, associated peripherals, and software used for specific purpose. All manufacturing organizations and sectors like telecommunications, banking, health care, avionics, automobile, food processing and also semiconductor industry etc.uses embedded system for automation. In fact the 90 percent of the microprocessors manufactured end up in embedded system.
Embedded System is combination of hardware and software that forms the component of larger system. Hardware is normally unique to given application. Computer chips are embedded into control electronics to manage the product’s functionality. The embedded system can be categories into four categories viz.; stand alone system, real-time system, network appliance system and mobile devices

1. INTRODUCTION

With advent of industrial automation, embedded systems have been around since the 1960s. An embedded system is a computing system hidden inside a product other than a computer. Hardware is designed Specific to the application (Not a general purpose).Software is developed as per the requirement and specific to the hardware.
All embedded systems use either a microprocessor or microcontroller. Some of the systems perform only some simple functions. Think about an automated vending machine that dispenses cool drinks. It has to collect the money from customer based on the product selected, dispense the product and balance money if any. Take another case of an embedded system that controls printer .This system has to execute more complex functions like checking for paper availability, printer ink, open door, paper jam, communication with host computer, data integrity etc are few of them.
Embedded real time systems are important components in a wide range of application areas including process industry, manufacturing automation, telecoms, power generation and distribution and defence. They act as an enabling technology allowing systems to sense their environments and directly influence them through controlled and timely action

2. CATEGORIES OF EMBEDDED SYSTEM

2.1 Stand-alone embedded systems:
As the name suggests, in a stand-alone mode work is taking input and producing output, which may be anything. Also the deadlines to carry out a specific task may not be strict; a few milliseconds variation not matter much. For example, an air conditioning unit can be set to turn on when the temperature is out of specified limit.

2.2 Real-time embedded systems:
Some embedded systems are required to carry out specific tasks in a specified time period. Such systems are called as Real time system.
Systems in which real-time constraints are to be strictly met are called hard real-time embedded system. Systems in which real-time constraints are not so critical are called as soft real-time embedded system.

2.3 Embedded systems for Networked appliances:
Some embedded systems are connected to a network. Even the Web server running HTTP can be embedded into the system. A typical example is to monitor some parameter in the system and sending information on internet for on-line monitoring.


2.4 Embedded system for Mobile devices:
With advent of wireless networks that support high speed, mobile devices are capable of supporting high data rates services in addition to the voice services. Accessing Internet services such as e-mail, the World Wide Web.

3. HARDWARE ARCHITECTURE

Processor:
The processor used in the embedded system can be specified by clock speed and data word-length. The choice of the processor depends upon the application in use.

Memory:
The memory used in an embedded processor can be either internal or external. The internal memory is very limited. For the small application if this memory is sufficient then no need to use external memory. Internal memory is faster than the external.

Latches and buffers:
Processor-based system need to drive external devices such as LED displays, relays, etc. the processor does not interact directly with these devices. Flip-flop logic chips are used to drive external devices. These chips hold the processor output data to be sent to the external devices.

Display units:
Some embedded system-for instance where system-user interaction is important, LCD or other displays are used.

Keypads & Communication devices:
Every embedded systems offer different capabilities for providing user input like keypad. For the embedded system to interact with the external devices, they need communication interface.

4. ADVANTAGES AND PITFALLS

4.1 Advantages
The advantages of Embedded are:
• The overall cost of system is reduced.
• Even if hardware is not re-usable the time-to-market advantage is clear and important
Consider the rapid evolution of domestic electronics, VCR’s, televisions and microwave cookers need control panels/timers. These can be designed and taken to production quicker using the highly-integrated functionality of microcontrollers to form the heart of the system.
• Other systems (machine tools, telephone switchgear...) can have software upgrades but utilise existing embedded hardware.
• Any systems which would have required expensive hardware upgrades in the past now need only software changes this can sometimes be done remotely, using communication links.
• Mechanical systems can be more effectively controlled by microprocessor
• Development time is reduced because of use of software on host system.
• More complex system can be developed in a simple way.

4.2 Pitfalls
The pitfalls or problems with development in embedded system is that hardware fabricated no chip can never be changed. Also embedded software programmers need to be aware of diversity of application areas and specific requirement for each.

5. APPLICATIONS OF EMBEDDED SYSTEMS

• Consumer electronics
Such as toys, air conditioners, refrigerators, microwave oven, CD player, mp3 players, TV sets, web enable TV sets are embedded system with varying processing power and memory requirements.
• Control systems & industrial automation
It includes fuel injection control, traction control, and climate control.
• Biomedical systems
Hospitals are full of embedded systems, including X- ray control unit, ECG and EEE units, equipment use for diagnostic testing such as Endoscopies.
• Data communication
The modems that connect two computers- yours with one own by your ISP-is an embedded system.
• Networked information appliances
With network, a web camera with embedded web server can be to the Internet to access web pages from desktop browser.
• Telecommunications
Telecommunication infrastructure include networking component such as telephones switches, ATM switches etc.
• Wireless communications
These include mobile phones, PDA, Bluetooth devices such as fax machines, modems cellular phones, speakers etc.

6. CONCLUSION

The world of embedded system is dreamer’s paradise with unlimited possibilities. Embedded system is rapidly becoming a catalyst for change in computing, data communication, telecommunications, industrial control etc. New innovative application in these areas will roll out in near future.

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