EMBEDDED SYSTEMS

INTRODUCTION:

To define an Embedded system we have lot of definitions such as:

An Embedded system is one that has computer hardware with software

embedded in it as one of its important components.

An Embedded system is a special-purpose system in which the computer is

completely encapsulated by the device it controls.

An Embedded system can also be defined as a computer system designed for

specific control functions within a larger system, often with real-time computing

constraints.

An Embedded device includes both hardware and mechanical parts.

An Embedded system contains processing cores that are either micro

controllers or digital signal processors (DSP).

An important point to be noted while discussing about Embedded systems is

that a processor is an important unit in the Embedded system hardware. It is the

heart of the Embedded system.

The main characteristic of an Embedded system is that it is being dedicated to

handle a particular task. Since the embedded system is dedicated to specific tasks,

design engineers can optimize it to reduce the size and cost of the product and

increase the reliability and performance.

In general an Embedded system has lot of applications.

Let us now discuss about the applications of Embedded systems in detail.

APPLICATIONS OF EMBEDDED SYSTEMS:

Embedded systems have wide range of applications in different fields. The

applications of Embedded system range from portable devices like digital watches

and MP3 players, to large stationary installations like traffic lights, factory controllers,

and largely complex systems like hybrid vehicles, MRI and avionics. Complexity varies

from low, with a single micro controller chip, to very high with multiple units,

peripherals and networks mounted inside a large enclosure. Embedded systems are

widespread in consumer, industrial, commercial and military applications.

Let us now discuss the category wise applications of Embedded systems.

Applications of Embedded systems in consumer electronics are as follows

Consumer electronics has also benefited a lot from Embedded systems. Consumer

electronics include:

Personal Digital Assistants(PDAs) Mp3 players Household appliances Mobile phones Videogame consoles Digital cameras DVD players GPS receivers Printers

Even the household appliances that include microwave ovens, washing

machines and dishwashers, are including washing machines to provide

flexibility, efficiency and features.

Applications of Embedded systems in Telecommunications are as follows:

The industry which uses mostly the Embedded system technology is nothing but

Telecommunication industry. The telecom industry utilizes numerous Embedded

systems from telephone switches for the network to mobile phones at the end-user.

Computer networking uses dedicated routers and network bridges to route data.

Embedded engineers help in ensuring high speed networking. This is the most critical

part of Embedded systems applications. The ethernet switches and network

interfaces are designed to provide the necessary bandwidth. This will allow in rapidly

incorporating ethernet connections into advanced Embedded applications.

Embedded systems were used for large, safety critical and business critical

applications that include

Rocket and satellite control Energy production control Telephone switches Air traffic control

Apart from the above applications embedded systems are also used in several other industries like

Transportation industry Fire safety Safety and security Medical Applications and Life critical systems as these systems can be isolated from hacking and thus

be more reliable.

Medical systems use Embedded systems for vital signs monitoring, electronic

stethoscopes for amplifying sounds and various medical imaging (PET, CT, MRI)

for non-invasive internal inspections. Embedded systems within medical

equipment is often powered by industrial computers.

CHARACTERISTICS OF EMBEDDED SYSTEMS:

Sophisticated functionality Real-time operation Low manufacturing cost Application dependent processor Restricted memory Low power

EMBEDDED SYSTEM CONSTRAINTS:

An Embedded system is software designed to keep in view three constraints:

1)Available system memory

2) Available Processor speed

2)The need to limit the power dissipation.

When running the system continuously in cycles of wait for event, run, stop and

wake- up.

WHAT MAKES EMBEDDED SYSTEM DIFFERENT?

Real-time operation Size Cost Time Safety Reliability Energy Security.

CLASSIFICATIONS OF EMBEDDED SYSTEMS:

Embedded systems are classified into three types:

1)Small scale Embedded systems

2)Medium scale Embedded systems

3)Sophisticated Embedded systems

Small scale Embedded systems contains single 8 bit or 16 bit microcontroller. It

has little hardware and software complexity. These small scale Embedded

systems may even be battery operated. Usually “C” is used to develop these

Embedded systems. The need to limit power dissipation when system is running

continuously. The Programming tools required for this kind of Embedded system

are: Editor, Assembler and Cross Assembler.

Medium Scale Embedded systems contains single or few 16 or 32 bit micro

controllers or DSP or RISC (Reduced Instruction Set Computer).It has both

hardware and software complexity. The Programming tools required for this kind

of Embedded system are:

RTOS, Source code engineering tool, Simulator, Debugger and Integrated

Development Environment (IDE).

Sophisticated embedded systems have enormous hardware and software

complexity. These kinds of Embedded systems need scalable processor or

configurable processor and PLA. These embedded systems are constrained by

the processing speed available in their hardware units. The Programming tools

required for this kind of Embedded system are:

For these Embedded systems programming tools may not be available at a

reasonable cost or may not be available at all. A compiler or retarget able

compiler must have to be developed for this kind of Embedded systems.

COMPONENTS OF EMBEDDED SYSTEM:

It has Hardware

Processor, Timers, Interrupt controller, I/O devices, Memories, Ports etc.

It has main application software which may perform concurrently the series

of tasks or multiple tasks.

It has Real time operating system(RTOS)

RTOS defines the way the system works which supervise the application

software .It sets the rules during the execution of the application program.

A small scale Embedded system may not need an RTOS.

A diagram for Embedded system hardware is shown below.

EMBEDDED SYSTEM HARDWARE

SPECIALITIES OF EMBEDDED SYSTEMS:

While designing the embedded systems, developers have to keep the below

specialties in mind: - Performance:-Many embedded systems have time constraints. For instance, in a process control

system, a constraint can be: “if the temperature exceeds 40 degrees, open a valve

within 10 milliseconds.” The system meets such deadlines.

If the deadlines are missed, it may result in a catastrophe. You can imagine the

damage that can be done if such deadlines are not met in a safety system of a nuclear

plant.

Power Consumption:-Most of the embedded systems operate through a battery. To reduce the battery

drain & avoid frequent recharging of the battery, the power consumption of an

embedded system has to be very low.

Cost:-For an embedded system used in safety applications of a nuclear plant or in a

spacecraft, cost may not be a very important factor. However, for an embedded

system used in consumer electronics or office automation, the cost is of utmost

importance. Suppose you have designed a toy in which the electronics will cost

US$20. By a careful analysis design, if you can telecom operator will change the

algorithm for the calculation of the bill amount. This is very cumbersome, considering

that a memory chip will have to replace in thousands of PCO.

Size: - Size is certainly a factor for many embedded systems. We do not like a mobile phone

that has to be carried on our backs. The size and the weight

(ie.compactness) are the important parameters in embedded systems used in

aircraft, missiles etc. because in such cases, every inch & every grain matters.

Software Up gradation capability:-Embedded systems are meant for a very specific task. So, once the software is

transferred to the embedded system, the same software will run throughout its life.

However, in some cases, it may be necessary its upgrade the software. Consider the

example of a Public Call Office (PCO).

At the PCO, an embedded system is used which displays the amount to be paid by a

telephone user. The amount is calculated by a firmware, based on the calling number

& the duration of the call from time to time, the broadband & wireless network, &

consumer electronic products.

RECENT TRENDS IN EMBEDDED SYSTEMS:-

In old good days, developing embedded systems was confined to very specialists.

Most of the embedded systems are written only in assembly language & hence

writing, debugging & maintaining the code were very difficult & time consuming.

With the availability of powerful processors & advanced development tools,

embedded software development is no longer ‘rocket science’.

Processor Power:-The growing importance of embedded systems can be gauged by the availability of

processors about 150 varieties of processors are available from around 50

semiconductor vendors. Powerful 8-bit, 16- bit, 32-bit and 64-bit micro controllers, &

microprocessors are available to cater to the different market segments the clock

speed & memory addressing capability of these processors are also increasing. Very

powerful digital signal processors are also available for real time analyses of audio

and video signals. As a result, the power of desktop computers is now available on

palm tops.Mobile Devices:-Mobile devices such as mobile phones, Personal Digital Assistants, smart phones etc.

are a special category of an embedded system. Though the PDA does many general-

purpose tasks, they need to be designed just like the conventional embedded

systems. The limitations of the mobile devices-memory constraints, small size, display

etc. are same as those found in the embedded systems. Hence mobile devices are

considered as embedded systems.

Operating Systems:- Unlike the desktop on which the options for an operating system are limited, a very

of operating systems are available which can be ported on to the embedded system.

The advantage of embedding an operating system is that the software development

will be very fast & marinating the code is very easy. The software can be developed in

a high level language such as “C”. So time to market the system gets reduced. If real

time performance is require a real time operating system can be used. In addition

too many commercial embedded operating system open source software

campaigned let to development of many open source operating system. The

attraction of open source software is that it is free & also the complete source code is

available to customize the software as per your application needs.Communication Interfaces and Networking Capability:-

With the availability of low-cost chips, embedded systems can be provided

networking capability through communication interfaces such as Ethernet, 802.11b

wireless LAN & infrared. Network enabling of an embedded system has many

advantages: it can be accessed over a network for remote control or monitoring.

Programming Languages:-Development of embedded system was done mostly in assembly languages.

However, due to the availability of cross-compilers, most of the development is now

done in high-level languages such as C. the object-oriented languages like C++ & Java

are now catching up.Development Tools:-

Availability of a number of tools for development, debugging & testing as well as for

modeling the embedded systems is now paving way for the fast development of

robust & reliable systems. Development tools such as BREW (Binary Routine

Environment for wireless), Wireless Application Protocol (WAP) development tools

facilitate easy development of applications for mobile devices.

Programmable Hardware:-

PLDs& FPGA pave the way for reducing the components on an embedded system,

leading to small, low-cost systems. After developing the prototype of an embedded

system, for mass production, FPGA can be developed having all the functionality of

the processors, peripherals & application-specific circuitry.

CONCLUSION:

An embedded system is closely integrated with the main system It may not interact

directly with the environment.Thus embedded systems contain programmed

instruction running via processor Chips. They perform control, protection &

monitoring tasks. In broad terms Embedded systems are programmable devices or

systems which are generally used to control or monitor things like processes

machinery, environmental equipment & communications. The range of

embedded system is vast & includes all industrial & commercial sectors. Embedded

systems are rapidly becoming a catalyst for change in the computing, data

communication, telecommunications, industrial control & entertainment sector. The

objective of this study is to enlighten readers about the application of embedded

systems; the embedded systems technology; & the impact of the technology on

various markets.