Embedded System Definition

Embedded System is a computer system in which software (Program) is embedded in computer hardware or the whole system itself is embedded in a larger system. Before proceeding further to know the exact definition of an embedded system, let’s have an idea about general purpose computer system. A general purpose computer has an Input unit (Keyboard), Processing unit (CPU) and Output unit (Monitor).  Processing unit includes Memory (RAM) & Storage (Hard disk) units. Each unit is easily replaceable and functions individually. The data flow from input unit to output unit is through processing unit. The processing unit also monitors input data, perform calculation and control output. A general purpose computer performs a lot of functions and allows connecting many devices and installing software. When a key is pressed on keyboard, CPU receives an input, processes the input and sends it to monitor.

Nowadays, we are using many devices in our daily routine. Most of the modern technology devices are electromechanical, built with mechanical, electrical and electronics components. It can be larger or smaller in size and simple or complex in design.

Microwave oven is a best example of electromechanical device. It consists mechanical components like chamber, turntable, motor, rotating knob, door & push button electrical components like transformers, lamp, fuse & electric motor and  electronics components capacitors, diode, control panel( Buttons and Display).

Microwave oven heats or cooks food for a period of time. It allows user to set/ adjust cook time and observe/cancel an ongoing operation digitally. Like a general purpose computer system, microwave oven has input unit (Buttons) and output unit (Display). These two units are on control panel and are visible to user. It also has a processing unit in control panel which is not visible to user and hidden inside the microwave oven. The processing unit has software in it and its functionality is predefined. One of its predefined functions is to detect the button pressed by user and send corresponding signs to display unit.  Unlike general purpose computer, the input, output and processing unit of microwave oven are fixed and interconnected in single circuit board and the individual component cannot be replaced by the user.

The control panel of microwave oven acts as a user interface and has small computer (controlling/processing unit) to receive user input and control outputs.  Here the control panel is an Embedded System since it has computer hardware & software embedded in it. The existence computer hardware and software may be unnoticed by end user of microwave oven. It is possible to build microwave oven without embedded system but it would not be easier and cheaper. The microwave oven system has an Embedded System in it and thus an example of embedded system.  Any device/system which has computer hardware & software (controlling/processing unit) embedded in it is called Embedded device/System. A general purpose computer system has many embedded system in it.

A pictorial comparison of computer systems: general purpose computer and microwave computer.

 Both are computer system but the one in microwave is part of a larger system. Microwave Oven, as a whole, is a system in which computer system is a sub or smaller system.  Computer system in microwave is specialized in hardware and software to perform predefined/dedicated function. Embedded system hardware and software is coupled together to perform its function.

Based on the above example an embedded system can be defined as,

An embedded system is a specialized computer system, a combination of special hardware and software, designed to perform a dedicated (one or more predefined) function. In an embedded system software is embedded in computer hardware, which in turn embedded in larger system. Embedded system may include mechanical, electrical or electronic components in addition to computer hardware and software. In most cases an embedded system is a component within some larger system.

A generic Embedded System,

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Related topics:
Embedded System Applications   |   Embedded System Characteristics   |   Embedded System Classification   |   Embedded System Components   |   Embedded System Symbols

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List of topics: Embedded System

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