• An embedded system can be defined as a control system or
computer system designed to perform a specific task.
Common examples of embedded systems include MP3
players, navigation systems on aircraft and intruder alarm
systems. An embedded system can also be defined as a single
• Embedded systems are more limited in hardware and/or
software functionality than a personal computer (PC).
oAn employs a combination of hardware & software (a
“computational engine”) to perform a specific function.
WHERE DOWE USE EMBEDDED SYSTEMS?
•· At Home: Washing Machines, dishwashers, ovens, central
heating system,burglars alarms, etc.
•· In Motor Vehicle: Engine management, security (locking or
antitheft devices), air conditioning, brakes, radio etc.
•· In Industry & Commerce: Machine control, factory
automation, robotics,electronic commerce office
CHARACTERISTICS OF EMBEDDED
Embedded Systems are designed to do some specific task
i.e., it is not a general purpose kind of a system.
Software for Embedded Systems are stored in ROM or
Knowledge about behavior at design time can be used to
minimize resources and to maximize robustness.
Embedded Systems provide low power consumption in
CLASSIFICATIONOF EMBEDDED SYSTEM
Stand alone Embedded system.
Real time Embedded system.
Mobile Embedded system.
EMBEDDED SYSTEM CAN BE CLASSIFIED :
Stand alone Embedded System:
It is built using a specialized communication processor, memory
a number of network access interfaces (known as network
ports), and special software that implements logic for sending
information from one device to another device.
Real Time Embedded System:
A realtime embedded system usually monitors the environment
where the embedded system is installed. This kind of system
isrequired to respond in time to a request. Examples of realtime
embedded systems are aircraft engine control systems, nuclear
monitoring systems and medical monitoring equipment.
· Network Appliances:
Network appliances are a new class of embedded
systems that in addition to traditional realtime
processing must support a broad and changing array of
· Mobile Embedded System:
Mobile Embedded Systems usually are
simple, batterypowered systems with resource
limitations. In some situations, their batteries lifetime
becomes a prim issue.
WHAT ISTHE DIFFERENCE BETWEEN AN
EMBEDDED SYSTEMAND A PERSONAL PC?
General Purpose Systems:
A general purpose computer system is what you think of when someone says
the word "computer." The defining feature of a general purpose computer is
that it can be reconfigured for a new purpose. In the early days of digital
computers, this involved actually rewiring the entire system. Today, most end
users aren't even aware that this is happening, as the process has become
An embedded system has a self-contained operating system on a "chip"
thus embedded into the system and does not rely on having a hard disk
with the operating system on it. Not to mention that is will be much faster
because the access time of the OS on a chip.
An embedded system has historically been defined as a single function
product where the intelligence is embedded in the system. It could be
anything from a dishwasher to a hearing aid, if that product includes a
microprocessor and software.
PRE-REQUISITION FOR EMBEDDED
WHAT IS MICROCONTROLLER ?
A Microcontroller is basically a computer on a chip.
It differs form normal desktop or laptop computers in that
a microcontroller is an application specific computer that
usually runs a single program performing dedicated task(s)
while the the later two are general purpose computers that
can run numerous programs depending on a users needs.
A microcontroller contains on chip CPU, input/output
interface, memory, clock, timer, and an assortment of of
WHAT IS MICROPROCESSOR?
A microprocessor incorporates the functions of
a computer's central processing unit(CPU) on a
single integrated circuit (IC) or at most a few integrated
circuits. It is a multipurpose, programmable device that
accepts digital data as input, processes it according to
instructions stored in its memory, and provides results as
output. It is an example of sequential digital logic, as it has
Assembly language is a low level language which we use for
microcontroller and microprosseser.
Assembly language is much harder to program than high level
The programmer needs to have a good understanding of the
hardware being used.
It used less memory and program can run much faster.
Assembly language allows the programmer to use symbolic
representation for machine operation codes (usually
called mnemonics), memory locations, registers and other parts
of an instruction.
WHY USE C?
It is a „mid-level‟, with „high-level‟ features (such as
support for functions and modules), and „low-level‟
features (such as good access to hardware via pointers);
It is very efficient;
It is popular and well understood;
Even desktop developers who have used only Java or
C++ can soon understand C syntax;
Good, well-proven compilers are available for every
embedded processor (8-bit to 32-bit or more);
CLASSIFICATION OF AN
EMBEDDED OPERATING SYSTEM
Non real time operating system:
NonReal Time Operating Systems do not guarantee defined
response times. Those systems are mostly used if multiple
applications are needed. Eg: window os.
Real time operating system:
Real Time Operating Systems are operating systems which
guarantee responses to each event within a defined amount
of time. Some commonly used RTOS for embedded systems
are:VxWorks, OS9,Symbian, and RTLinux etc
LINUX OPERATING SYSTEM
Multiple choices vs. sole source
Source code freely available
Robust and reliable
Modular, configurable, scalable
Superb support for networking and Internet
No runtime licenses
Large pool of skilled developers
EMBEDDED SYSTEM DESIGN
•Creating the artitechure.
•Testing the system.
•Maintaining the system.
Aerospace NavigationSystems, Automatic
landing systems, Flight altitude
Industrial ElevatorControls, Robots, Engine
Medical Imaging system,pateint
Office automation FAX machines,Telephones, Cash
Computer Peripherals Printers,scanners,keyboards,display
Home Oven,washing machine.
-They are designed to do a specific task and have real time
performance constraints which must be met.
- They allow the system hardware to be simplified so costs are
- They are usually in the form of small computerized parts in
larger devices which serve a general purpose.
- The program instructions for embedded systems run with
limited computer hardware resources, little memory and small
or even non-existent keyboard or screen.
Designing Embedded Hardware John Catsoulis, O'Reilly, May
2005, ISBN 0-596-00755-8.
Michael Barr; Anthony J. Massa
(2006). "Introduction". Programming embedded systems:
with C .