CS244-Introduction to Embedded Systems and Ubiquitous ComputingCS244 – Lecture 3Course OutlineComponents of Embedded SystemsDesign DomainsDigitalSoftwareSlide 8Slide 9Real-time SystemsHard Real-timeFirm Real-timeSoft Real-TimeEmbedded Operating SystemsCS244-Introduction to Embedded Systems and Ubiquitous ComputingInstructor: Eli BozorgzadehComputer Science DepartmentUC IrvineWinter 2012Winter 2010- CS 2442CS244 – Lecture 3Embedded System SoftwareWinter 2010- CS 2443Course Outline ConceptConceptSpecificationSpecificationHW/SWHW/SWPartitioningPartitioningHardware ComponentsHardware ComponentsSoftware ComponentsSoftware ComponentsEstimation -Estimation -ExplorationExplorationHardwareHardwareSoftwareSoftwareDesignDesign(Synthesis, Layout, …)(Synthesis, Layout, …)DesignDesign(Compilation, …)(Compilation, …)Validation and Evaluation (area, power, performance, …)Validation and Evaluation (area, power, performance, …)Winter 2010- CS 2444Components of Embedded SystemsAnalogDigital AnalogMemoryCoprocessorsControllersConvertersProcessorInterfaceSoftware(Application Programs)ASIC5Design Domains5MechanicsHydraulicsActuatorsCircuit BoardsPackagingPanel & BodyMEMSNanotechnologiesAntennasRF ModulatorsMixersAmplifiersVCOsSensorsA/D & D/APower DriversFiltersSignal ConditionersOp. AmpsTransistorsPassive DevicesPower SupplyAC/DC & DC/DCSystem ArchitectureProcessorsMemoriesALU, MUX, & LatchesGates & FFCMOS TransistorsMasksUser SoftwareGUIUser LibrariesSystem LibrariesVMMiddlewareDevice DriversRTOSBIOS & FirmwareOther Analog Digital SoftwareWinter 2010- CS 2446DigitalSystem architectureHow many processors (custom and general purpose)The interconnect networkThe memory hierarchy and DMA architectureIn some designs, system architecture may include softwareProcessorsInstruction set architecturePipeline design and datapathControllerRTL descriptionMemoriesOn-chip (small) memories may be based on Flip Flops (see next slide)For larger fabrics, often based on DRAM, magnetic media, or laser readable media6ReliableVery ReliableWinter 2010- CS 2447SoftwareUser level software (ULS)Highly application specificLow reusabilityTypically designed at the last phaseGUIOften part of ULSMay be based on standard GUI libraries (X11, Java, WinCE, GNOME, KDE, etc.)Often requires more research and refinement than it receivesMay be the most complex/challenging design component, especially in display/input limited devicesUser librariesReusable application softwareDSP algorithms and application kernels7 Front End Back End Mini KernelLeast ReliableWinter 2010- CS 2448Software System librariesHighly reusable application softwareImplementation of standards (e.g., MPEG), custom database engines, GUI kernels, etc.VMEmulates a portable and documented “fictitious” machine (and perhaps API) on any underlying processing systemMiddlewareProvide a unique interface between applications, lower level hardware, the grid, or a network of devicesSoftware that connects two otherwise separate applicationsDevice driversAPI to manipulate, read, and write hardware devicesHighly hardware dependent codeDifficult to debug8ReliableWinter 2010- CS 2449SoftwareRTOSProvides, multitasking, scheduling, communication, and synchronization between threads of executionBIOSProvides very basic API for accessing the underlying computer platformFirmwareSoftware that is embedded in a system that does not allow modification by an end userMay contain BIOS, RTOS, Middleware, …, ULSOr, may contain all but ULSOr, some hybrid9Winter 2010- CS 24410Real-time SystemsA real-time system has to produce correct result at the right time (deadline driven)A real-time system imposes stringent timing requirements in addition to correctness Hard real-timeFirm real-timeSoft real-timeWinter 2010- CS 24411Hard Real-timeSystem designed to meet all deadlinesA missed deadline is a design flawExamples:Shuttle navigation systemNuclear reactor monitoring systemSystem hardware (over) designed for worst-case performanceSystem software vigorously testedFormal proofs used to guarantee timing correctnessWinter 2010- CS 24412Firm Real-timeSystem designed to meet all deadlines, but“Occasional” missed deadline is allowedSometimes statistically quantified (e.g., 5% misses)No need to compute further once a deadline is missedExamples:Multimedia systemsSystem hardware designed for average case performanceSystem software tested under average (ideal) conditionsWinter 2010- CS 24413Soft Real-TimeSystem designed to meet as many deadlines as possibleBest effort to complete within specified time, but may be lateExamples:Network switch or routerSystem hardware designed for average case performanceSystem software tested under average (ideal) conditionsWinter 2010- CS 24414Embedded Operating SystemsMust provide means for dynamic task creationCreate, join, and cancelMust provide means for task synchronization and communicationShared memory vs. message passingSemaphore and condition variables vs. monitorsPosix threads a common standard provides thread creation and