EMBEDDED SYSTEMS

An embedded system is a computer system designed for specific control functions within a larger system, often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal computer (PC), is designed to be flexible and to meet a wide range of end-user needs. Embedded systems control many devices in common use today
Embedded systems contain processing cores that are typically either microcontrollers or digital signal processors (DSP)The key characteristic, however, 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. 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, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants.

Telecommunications systems employ 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.

HISTORY

Since these early applications in the 1960s, embedded systems have come down in price and there has been a dramatic rise in processing power and functionality. The first microprocessor for example, the Intel 4004, was designed for calculators and other small systems but still required many external memory and support chips. In 1978 National Engineering Manufacturers Association released a "standard" for programmable microcontrollers, including almost any computer-based controllers, such as single board computers, numerical, and event-based controllers

The integration of microcontrollers has further increased the applications for which embedded systems are used into areas where traditionally a computer would not have been considered. A general purpose and comparatively low-cost microcontroller may often be programmed to fulfill the same role as a large number of separate components. Although in this context an embedded system is usually more complex than a traditional solution, most of the complexity is contained within the microcontroller itself

APPLICATIONS

Embedded System Applications describes the latest techniques for embedded system design in a variety of applications. This includes some of the latest software tools for embedded system design. Applications of embedded system design in avionics, satellites, radio astronomy, space and control systems are illustrated in separate chapters. Finally, the book contains chapters related to industrial best-practice in embedded system design.
Embedded System Applications will be of interest to researchers and designers working in the design of embedded systems for industrial applications.

Embedded Systems has witnessed tremendous growth in the last one decade. Almost all the fast developing sectors like automobile, aeronautics, space, rail, mobile communications, and electronic payment solutions have witnessed increased use of Embedded technologies and their applications. Greater value to mobility is one of the prominent reasons for the rise and development of Embedded technologies.

Initially, Embedded Systems were used for large, safety-critical and business-critical applications that included

• Rocket & satellite control
• Energy production control
• Telephone switches
• Air Traffic Control

EMBEDDED SYSTEMS IN TELECOMMUNICATIONS

If ever there is an industry that has reaped the benefits to Embedded Technology, for sure, it is only Telecommunications.  The Telecom industry utilizes numerous embedded systems from telephone switches for the network to mobile phones at the end-user. The Telecom computer network also 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 applications. The Ethernet switches and network interfaces are designed to provide the necessary bandwidth. These will allow in rapidly incorporating Ethernet connections into advanced Embedded applications.Embedded application types range from high availability telecom and networking applications to rugged industrial and military environments.

Consumer Electronics

Consumer electronics has also benefited a lot from Embedded technologies. Consumer electronics includes

• Personal Digital Assistants (PDAs)
• MP3 players
• 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 embedded systems to provide flexibility, efficiency and features. The latest in Embedded applications are seen as advanced HVAC systems that uses networked thermostats to more accurately and efficiently control temperature.  

In the present times, home automation solutions are being increasingly built on Embedded technologies. Home automation includes wired and wireless-networking to control lights, climate, security, audio/visual, surveillance, etc., all of which use embedded devices for sensing and controlling.

User interface

Embedded systems range from no user interface at all — dedicated only to one task — to complex grafical user interface that resemble modern computer desktop operating systems. Simple embedded devices use buttons, LEDs, graphic or character LCD (for example popular HD44780 LCD) with a simple menu system.

More sophisticated devices which use a graphical screen with touch sensing or screen-edge buttons provide flexibility while minimizing space used: the meaning of the buttons can change with the screen, and selection involves the natural behavior of pointing at what's desired

Debugging

Embedded debugging may be performed at different levels, depending on the facilities available. From simplest to most sophisticated they can be roughly grouped into the following areas:

• Interactive resident debugging, using the simple shell provided by the embedded operating system (e.g. Forth and Basic)
• External debugging using logging or serial port output to trace operation using either a monitor in flash or using a debug server like the Remedy Debugger which even works for heterogeneous multicore systems.
• An in-circuit debugger (ICD), a hardware device that connects to the microprocessor via a JTAG or Nexus interface. This allows the operation of the microprocessor to be controlled externally, but is typically restricted to specific debugging capabilities in the processor.
• An in-circuit emulator (ICE) replaces the microprocessor with a simulated equivalent, providing full control over all aspects of the microprocessor.

Reliability

Embedded systems often reside in machines that are expected to run continuously for years without errors, and in some cases recover by themselves if an error occurs. Therefore the software is usually developed and tested more carefully than that for personal computers, and unreliable mechanical moving parts such as disk drives, switches or buttons are avoided.

Specific reliability issues may include:

• The system cannot safely be shut down for repair, or it is too inaccessible to repair. Examples include space systems, undersea cables, navigational beacons, bore-hole systems, and automobiles.
• The system must be kept running for safety reasons. "Limp modes" are less tolerable. Often backups are selected by an operator. Examples include aircraft navigation, reactor control systems, safety-critical chemical factory controls, train signals.
• The system will lose large amounts of money when shut down: Telephone switches, factory controls, bridge and elevator controls, funds transfer and market making, automated sales and service

EMBEDDED SOFTWARE

Embedded software is computer software that plays an integral role in the electronics it is supplied with.
Embedded software's principal role is not information technology (i.e. it is not about information and the technologies related to providing information services), but rather the interaction with the physical world. It's written for machines that are not, first and foremost, computers. Manufacturers 'build in' embedded software in the electronics in cars, telephones, audio equipment, robots, appliances, toys, security systems, pacemakers, televisions and digital watches, for example. This software can become very sophisticated in applications such as airplanes, missiles, and process control systems

COMPONENTS OF EMBEDDED SOFTWARE:

(1) Control Software: Control Software (also known as firmware) is responsible for managing (and synchronizing) different modules of the system.
(2) Computation Extensive Software : Computational Software is responsible for performing Mathematical and Logical Operations on the Input Data. The output of this processing can either be sent back (to another system), or stored (in systems memory) for later use, or can be used by the control software to take certain decisions (and do further processing based on these decisions).
(3) Device Drivers: Device Drivers are Software Modules which control System's Peripheral. (j) User Interface: This software is responsible for collecting user inputs (from input devices like keypad or touch screen) and providing “ User Menu ” or “System Status ” to the User (through Display Devices)
(4) Operating System (optional) : Operating System is a software which manages the different resources (CPU, Memory, Peripherals) of a system and provides a abstration of the underlying hardware to the Users. Application developers can develop their applications (to be run on the Operating System) without having to learn much about the underlying Hardware. Operating System is optional in Embedded Systems (unlike Desktop environment where it is the most essential software).

EMBEDDED SYSTEMS IN PRESENT WORLD

Modern embedded systems, however, are increasingly taking on characteristics of general-purpose systems. Their functionality is growing, and so is the amount and complexity of their software.Yet some of the old differences to general-purpose systems remain. Embedded devices are still real-time systems (or at least part of the software is real-time).At the same time, embedded systems, already ubiquitous, are becoming more and more part of everyday life, to the degree that it is becoming hard to imagine living without them. They are increasingly used in mission- and life-critical scenarios. Correspondingly, there are high and increasing requirements on safety, reliability and security.