Sunday, February 6, 2011

Embedded System

Embedded System

An embedded system is system which is designed to perform one or a few dedicated functions, often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. Embedded systems control many of the common devices in use today. Embedded systems are controlled by a main processing core that is typically either a microcontroller or a digital signal processor (DSP).

Since the embedded system is devoted to specific tasks, design engineers can optimize it, reducing the size and cost of the product, or increasing the reliability and performance. Some embedded systems are mass-produced, benefiting from economies of scale.

Physically, embedded systems range from portable devices such as digital watches and MP3 players, large stationary installations like traffic lights, factory controllers or the systems controlling nuclear power plants. Complexity varies from low, with a single microcontroller chip, to very high with multiple units, peripherals and networks mounted inside a large framework or enclosure.

Characteristics:

1. Embedded systems are designed to do some specific tasks, rather than be a general-purpose computer for multiple tasks often with real-time computing constraints.

2. Embedded systems are not always standalone devices. Many embedded systems consist of small, computerized parts within a larger device that serves a more general purpose.

3. The program instructions written for embedded systems are referred to as firmware, and are stored in read-only memory or Flash memory chips. They run with limited computer hardware resources such as little memory, small or non-existent keyboard and/or screen.

Tools:

Embedded system designers use compilers, assemblers, and debuggers to develop embedded system software. However, they may also use some more specific tools such as emulators.For systems using digital signal processing, developers may use a math workbench such as Scilab / Scicos, MATLAB / Simulink, EICASLAB, MathCad, or Mathematica to simulate the mathematics. They might also use libraries for both the host and target which eliminates developing DSP routines as done in DSPnano RTOS and Unison Operating System.Custom compilers and linkers may be used to improve optimisation for the particular hardware.An embedded system may have its own special language or design tool, or add enhancements to an existing language such as Forth or Basic. Designers can also add a Real-time operating system or Embedded operating system, which may have DSP capabilities like DSPnano RTOS.

Software tools can come from several sources:

  • Software companies that specialize in the embedded market
  • Ported from the GNU software development tools
  • Sometimes development tools for a personal computer can be used if the embedded processor is a close relative to a common PC processor

As the complexity of embedded systems grows, higher level tools and operating systems are migrating into machinery where it makes sense. For example, cell phones, personal digital assistants and other consumer computers often need significant software that is purchased or provided by a person other than the manufacturer of the electronics. In these systems, an open programming environment such as Linux, NetBSD, OSGi or Embedded Java is required so that the third-party software provider can sell to a large market.

CPU platforms:

Embedded processors can be broken down into two broad categories: ordinary microprocessors (μP) and microcontrollers (μC), which have many more peripherals on chip, reducing cost and size. Contrasting to the personal computer and server markets, a fairly large number of basic CPU architectures are used; there are Von Neumann as well as various degrees of Harvard architectures, RISC as well as non-RISC and VLIW; word lengths vary from 4-bit to 64-bits and beyond mainly in DSP processors, although the most typical remain 8/16-bit. Most architecture come in a large number of different variants and shapes, many of which are also manufactured by several different companies.


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This article is the topic of 7th unit from RTMNU MBA 3 rd sem IT syllabus notes.Further topics will be covered in upcoming blogs For more notes you can also refer to other links as given below:

  1. http://rtmnupervasivecomp.blogspot.com
  2. http://rtmnuittrends.blogspot.com
  3. http://www.rtmnunetworkingtechnology.blogspot.com


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