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Measures of Dispersion and Variability: Range, QD, AD and SD
Embedded systems- nanocdac
1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. 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).
9. 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.
10. 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.
11. 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.