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Embedded software

What is embedded software ?

Embedded softwareis computersoftware, written to control machines or devices that are not typically thought of as computers. It is typically specialized for the particular hardwarethat it runs on and has time and memory constraints. A precise and stable characteristic feature is that no or not all functions of embedded software are initiated/controlled via a human interface, but through machine-interfaces instead.

Manufacturers 'build in' embedded software in the electronics incars, telephones, modems,robots, appliances, toys, security systems,pacemaker, televisions andset-top boxes, anddigital watches, for example.This software can be very simple, such as lighting controls running on an 8-bit microprocessor and a fewkilobitesof memory. Operating systemsUnlike standard computers that generally utilise a small number of operating systems (largely OS X, Windows and GNU/Linux), embedded software comes in a wide variety of operating systems, typically areal-time operating system. This runs from small one-person operations consisting of a run loop and a timer, toLynxOS,BeRTOS,ThreadX, toWindows CEorLINUX(with patched kernel). Others includePikeOS,eCos,Fusion RTOS,Nucleus RTOS,INTEGRITY,uC/OS,QNX,FreeBSD andOSE. Code is typically written inC orC++.Adais used in some military and aviation projects.

Most consumers are familiar withapplication softwarethat provide functionality on a computer. Embedded software however is often less visible, but no less complicated. Unlike application software, embedded software has fixed hardware requirements and capabilities, addition of third-party hardware or software is strictly controlled.Software development requires use of across compiler, which runs on a computer but produces executable code for the target device. Debugging requires use of anin-circuit emulator,JTAGorSWD. Software developers often have access to the complete kernel (OS) source code.Communication protocolsCommunications between processors and between one processor and other components are essential. Besidesdirect memory addressing, common protocols includeIC,SPI, serial ports, andUSB.Communications protocols designed for use inembedded systemsare available asclosed sourcefrom companies includingInterNiche TechnologiesandCMX Systems.Open-sourceprotocols stem fromuIP,lwip, and others.

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