An embedded
system is a system which is going to do a predefined specified task is the
embedded system and is even defined as combination of both software and
hardware. 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. At the other extreme a general-purpose computer
may be used to control the operation of a large complex processing plant, and
its presence will be obvious.
All
embedded systems are including computers or microprocessors. Some of these
computers are however very simple systems as compared with a personal computer.
The very
simplest embedded systems are capable of performing only a single function or
set of functions to meet a single predetermined purpose. In more complex
systems an application program that enables the embedded system to be used for
a particular purpose in a specific application determines the functioning of
the embedded system. The ability to have programs means that the same embedded
system can be used for a variety of different purposes. In some cases a
microprocessor may be designed in such a way that application software for a
particular purpose can be added to the basic software in a second process,
after which it is not possible to make further changes. The applications
software on such processors is sometimes referred to as firmware.
The simplest
devices consist of a single microprocessor (often called a "chip”), which
may itself be packaged with other chips in a hybrid system or Application
Specific Integrated Circuit (ASIC). Its input comes from a detector or sensor
and its output goes to a switch or activator which (for example) may start or
stop the operation of a machine or, by operating a valve, may control the flow
of fuel to an engine.
As the embedded system is the
combination of both software and hardware