CS/ECE 5780/6780: Embedded SystemDesignJohn RegehrLecture 1: Introduction to Embedded SystemsEmbedded systems: definitionIAn embedded system is :Ia special-purpose computer designed to perform dedicatedfunctions often with real-time constraints.Ia system embedded as part of a complete system .Ireally any system that is not a PC...although PCs containseveral embedded systems.Embedded systems: functionIFive main categories:IDigital signal processingIControlINetworkingIUser interfacingIData storageIMost e mbedded systems perform more than one of thesefunctions.Popularity with consumersI>99% of new microprocessors are found in embedded systems.ICnet’s Top 10 Must-havesIApple iPhoneIApple iPod NanoIVuduINintendo WiiIApple MacBookISling Media Slingbox A/VISony PSPISamsung LN-T4665FISony Handycam HDR-CX7IShure SE110 Sound Isolating EarphonesPopularity with other industriesIAutomotiveIAir bag controllersIAnti-lock brakesICommunicationsISatellite phonesICell phone base stationsIIndustrialIPoint-of-sale systemsIRoboticsIMedicalILife-supportIMedical testingIMilitaryIGPSIMissile guidanceEmbedded systems designIWhy is it unique?IComputation is subject to physical constraints such as timingdeadlines, memory restrictions, and power consumptionrequirements.IThe traditional abstraction of separating software from thehardware and environment does not work.IHardware, software, and control are integrally intertwined.IDesigners must understand both hardware, software, andcontrol.I”The Embedded Systems Design Challenge” by Henzingerand Sifakis continues this discussion.Top-Down Design ProcessAnalysis PhaseIDiscover the requirements and constraints.IRequirements are general parameters that the system mustsatisfy.ISpecifications are detailed, specific requirements.IConstraints are limitations under which the system mustoperate.Embedded system design metricsINonrecurring engineering costIUnit costISize & weightIPerformance (accuracy, precision, resolution, response time,bandwidth)IPowerIFlexibility, mai ntainabili ty, reliability, testability, &compatibilityITime-to-prototypeITime-to-marketICorrectnessISafetyILook & feelHigh-Level Design PhaseIBuild a conceptual model of the hardware and softwaresystem.IDesign broken into modules or subcomponents.IEstimate cost, schedule, and expected performan ce.IDevelop a data flow graph for the system.Data Flow Graph for a Motor ControllerEngineering Design PhaseIConstruct a preliminary design.IThis should include the hierarchical structure, basi c I/Osignals, shared data structures, and overall software scheme.IBuild mock-ups of mechanical parts and user softwareinterface.ICall graphs can be used to show how software and hardwareinteract.Call Graph for a Motor ControllerImplementation PhaseIDuring this phase, the design is actually built.IImplementation of subcomponents may actually be startedduring the earlier phases.IDebugging embedded systems can be very diffic ult.ITherefore, extensive use of hardware/software simulation andcosimulation is essential.Testing PhaseIDuring this phase, we evaluate the performance.IFirst, debug and validate the b asic functions of the system.INext, evaluate and optim ize various performance parameterssuch as execution speed, accuracy, and stability.Maintenance PhaseIDuring this phase, we:ICorrect mistakes,IAdd new features,IOptimize execution speed or program size,IPort to new computers or operating systems, andIReconfigure the system to solve a similar problem.IMust be able to deal with changes in requirements orconstraints.INot actually another phase, but more loops through the entirecycle.Bottom-Up Design ProcessBasic Components of a Computer SystemMemory-Mapped Computer SystemIsolated I/O Computer SystemMemory Read CycleDMA Read
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