Introduction to Embedded Systems

Introduction to Introduction to Embedded Embedded

SystemsSystems

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ObjectivesObjectives

• Introduction to embedded systemsIntroduction to embedded systems• Embedded system componentsEmbedded system components

• HardwareHardware• SoftwareSoftware

• Embedded system programmingEmbedded system programming• Hardware Description Language (HDL)Hardware Description Language (HDL)

Introduction to Embedded SystemsIntroduction to Embedded Systems Setha Pan-ngum Setha Pan-ngum

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ContentsContents

• Introduction to embedded systemsIntroduction to embedded systems• Software engineeringSoftware engineering• Computer architectureComputer architecture• Operating systemsOperating systems• Digital systemsDigital systems• Programming practiceProgramming practice• Theory for practical worksTheory for practical works


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ContentsContents

• Lab: Software programming toolsLab: Software programming tools• Introduction to hardware systhesisIntroduction to hardware systhesis• Lab: External interfaceLab: External interface


5Introduction to Embedded SystemsIntroduction to Embedded Systems Setha Pan-ngum Setha Pan-ngum

Y. Williams Csci-339, Spring 2002 20

Wireless Communications

Hand-held GPS Units

Telematics System for Automobiles

Slide credit Y Williams, GWUSlide credit Y Williams, GWU



Robotics Control

Spider robot – constructed with LEGO Mindstorms Components


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More examplesMore examples




Smart Toys

8Introduction to Embedded SystemsIntroduction to Embedded Systems Setha Pan-ngum Setha Pan-ngumSlide credit Y Williams, GWUSlide credit Y Williams, GWU


Cruise Missile Guidance

9Slide credit S. Kowalewski Aachen UniversitySlide credit S. Kowalewski Aachen University


10Slide credit P Koopman, CMUSlide credit P Koopman, CMUIntroduction to Embedded SystemsIntroduction to Embedded Systems Setha Pan-ngum Setha Pan-ngum

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DefinitionDefinition

““Any sort of device which includes a Any sort of device which includes a programmable computer but itself is not programmable computer but itself is not intended to be a general-purpose intended to be a general-purpose computercomputer””

Wayne WolfWayne Wolf


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DefinitionDefinition

Slide credit P Koopman, CMUSlide credit P Koopman, CMU


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Embedded systems overviewEmbedded systems overview Computing systems are everywhereComputing systems are everywhere Most of us think of “desktop” computersMost of us think of “desktop” computers

– PC’sPC’s– LaptopsLaptops– MainframesMainframes– ServersServers

But there’s another type of computing systemBut there’s another type of computing system– Far more common...Far more common...

Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 20002000


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Embedded systems overviewEmbedded systems overview Embedded computing systemsEmbedded computing systems

– Computing systems embedded Computing systems embedded within electronic deviceswithin electronic devices

– Hard to define. Nearly any Hard to define. Nearly any computing system other than a computing system other than a desktop computerdesktop computer

– Billions of units produced yearly, Billions of units produced yearly, versus millions of desktop unitsversus millions of desktop units

– Perhaps 50 per household and per Perhaps 50 per household and per automobileautomobile

Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000Hardware/Software Introduction, 2000

Computers are in here...

and here...

and even here...

Lots more of these, though they cost a lot

less each.


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A “short list” of embedded A “short list” of embedded systemssystems

And the list goes on and onAnd the list goes on and onSlide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000

Anti-lock brakesAuto-focus camerasAutomatic teller machinesAutomatic toll systemsAutomatic transmissionAvionic systemsBattery chargersCamcordersCell phonesCell-phone base stationsCordless phonesCruise controlCurbside check-in systemsDigital camerasDisk drivesElectronic card readersElectronic instrumentsElectronic toys/gamesFactory controlFax machinesFingerprint identifiersHome security systemsLife-support systemsMedical testing systems

ModemsMPEG decodersNetwork cardsNetwork switches/routersOn-board navigationPagersPhotocopiersPoint-of-sale systemsPortable video gamesPrintersSatellite phonesScannersSmart ovens/dishwashersSpeech recognizersStereo systemsTeleconferencing systemsTelevisionsTemperature controllersTheft tracking systemsTV set-top boxesVCR’s, DVD playersVideo game consolesVideo phonesWashers and dryers


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How many do we use?How many do we use? Average middle-class American home has 40 to 50 Average middle-class American home has 40 to 50

embedded processors in it embedded processors in it – Microwave, washer, dryer, dishwasher, TV, VCR, Microwave, washer, dryer, dishwasher, TV, VCR,

stereo, hair dryer, coffee maker, remote control, stereo, hair dryer, coffee maker, remote control, humidifier, heater, toys, etc. humidifier, heater, toys, etc.

Luxury cars have over 60 embedded processorsLuxury cars have over 60 embedded processors– Brakes, steering, windows, locks, ignition, dashboard Brakes, steering, windows, locks, ignition, dashboard

displays, transmission, mirrors, etc. displays, transmission, mirrors, etc. Personal computers have over 10 embedded Personal computers have over 10 embedded

processors processors – Graphics accelerator, mouse, keyboard, hard-drive, CD-Graphics accelerator, mouse, keyboard, hard-drive, CD-

ROM, bus interface, network card, etc. ROM, bus interface, network card, etc. - Mike Schulte- Mike Schulte


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Embedded Systems =Embedded Systems = ระบบระบบฝังตัวฝังตัว คิดถึงคอมพวิเตอร์ พซีี เรานึกถึง คิดถึงคอมพวิเตอร์ พซีี เรานึกถึง

– ProcessorProcessor, , Clock speedClock speed, , ROM/RAMROM/RAM พูดถึงเครื่องใชไ้ฟฟา้ทัว่ไป เรานึกถึง พูดถึงเครื่องใชไ้ฟฟา้ทัว่ไป เรานึกถึง

ทีวีทีวี - - ขนาดจอขนาดจอ, , เทคโนโลยกีารฉายภาพเทคโนโลยกีารฉายภาพ เครื่องซกัผ้า เครื่องซกัผ้า - - ขนาดความจุขนาดความจุ, , ระบบซกัระบบซกั

แอร ์แอร์ - - BTUBTU ลักษณะการติดตัง้ลักษณะการติดตัง้ โทรศัพท์มื่อถือ โทรศัพท์มื่อถือ - - จอ กล้อง ฟงัก์ชัน่ จอ กล้อง ฟงัก์ชัน่

รถยนต์ รถยนต์ - - ขนาดเครื่องยนต์ สมรรถนะ ขนาดเครื่องยนต์ สมรรถนะ


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Types of Embedded SystemsTypes of Embedded Systems

Slide credit P Koopman, CMUSlide credit P Koopman, CMU


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Types of Embedded SystemsTypes of Embedded Systems

Slide credit S. Kowalewski Aachen UniversitySlide credit S. Kowalewski Aachen University


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Typical Embedded SystemsTypical Embedded Systems

Are designed to observed (through sensors) Are designed to observed (through sensors) and control something (through actuators)and control something (through actuators)E.g. air condition senses room temperature and E.g. air condition senses room temperature and

maintains it at set temperature via thermostat.maintains it at set temperature via thermostat.


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Embedded System Block DiagramEmbedded System Block Diagram



Processor

mem

Observe(Input)

Control(Output) Motor/Light

TemperatureSensor

System B

us

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ProcessorsProcessors

Microprocessors for PCsMicroprocessors for PCs Embedded processors or Microcontrollers Embedded processors or Microcontrollers

for embedded systemsfor embedded systems– Often with lower clock speeds Often with lower clock speeds – Integrated with memory and Integrated with memory and – I/O devices e.g. A/D D/A PWM CANI/O devices e.g. A/D D/A PWM CAN– Higher environmental specsHigher environmental specs


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Microcontrollers dominates processor marketMicrocontrollers dominates processor market


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There are so many microcontrollers in the There are so many microcontrollers in the worldworld


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Types of Embedded ProcessorsTypes of Embedded Processors Computational micros (32- or 64-bit datapaths)Computational micros (32- or 64-bit datapaths)

– CPU of workstations, PCs, or high-end portable devices (PDAs)CPU of workstations, PCs, or high-end portable devices (PDAs)– x86, PA-RISC, PowerPC, SPARC, etc. x86, PA-RISC, PowerPC, SPARC, etc.

Embedded general purpose micros (32-bit datapaths)Embedded general purpose micros (32-bit datapaths)– Designed for a wide range of embedded applicationsDesigned for a wide range of embedded applications– Often scaled-down version of computational microsOften scaled-down version of computational micros– ARM, PowerPC, MIPS, x86, 68K, etc. ARM, PowerPC, MIPS, x86, 68K, etc.

Microcontrollers (4-, 8-, or 16-bit datapaths)Microcontrollers (4-, 8-, or 16-bit datapaths)– Integrate processing unit, memory, I/O buses, and peripheralsIntegrate processing unit, memory, I/O buses, and peripherals– Often low-cost, high-volume devicesOften low-cost, high-volume devices

Domain-specific processors (datapath size varies greatly)Domain-specific processors (datapath size varies greatly)– Designed for a particular application domainDesigned for a particular application domain– Digital signal processors, multimedia processors, graphics Digital signal processors, multimedia processors, graphics

processors, network processors, security processors, etc. processors, network processors, security processors, etc. Slide credit - Mike SchulteSlide credit - Mike Schulte


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Processor Sales DataProcessor Sales Data

Slide credit - Mike SchulteSlide credit - Mike Schulte


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Processor MarketProcessor Market 2001 processor market by volume:2001 processor market by volume:

– Computational micros: 2%Computational micros: 2%– Embedded general-purpose micros: 11%Embedded general-purpose micros: 11%– DSPs: 10%DSPs: 10%– Microcontrollers: 80%Microcontrollers: 80%

2001 processor market by revenue:2001 processor market by revenue:– Computational micros: 51%Computational micros: 51%– Embedded general-purpose micros: 8%Embedded general-purpose micros: 8%– DSPs: 13%DSPs: 13%– Microcontrollers: 28%Microcontrollers: 28%

Higher growth expected for embedded micros, DSPs, and Higher growth expected for embedded micros, DSPs, and microcontrollersmicrocontrollers



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Growing DemandGrowing Demand

Embedded Embedded processors account processors account for for – Over 97% of total Over 97% of total

processors soldprocessors sold– Over 60% of total Over 60% of total

sales from processors sales from processors Sales expected to Sales expected to

increase by roughly increase by roughly 15% each year15% each year



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Moore’s LawMoore’s Law

Slide credit – W FornaciariSlide credit – W Fornaciari


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Number of Transistors on ChipsNumber of Transistors on Chips

Slide credit – T GivargisSlide credit – T Givargis


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Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000


Graphical illustration of Moore’s law

1981 1984 1987 1990 1993 1996 1999 2002

Leading edgechip in 1981

10,000transistors

Leading edgechip in 2002

150,000,000transistors

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Some common characteristics of embedded Some common characteristics of embedded systemssystems

Single-functionedSingle-functioned– Executes a single program, repeatedlyExecutes a single program, repeatedly

Tightly-constrainedTightly-constrained– Low cost, low power, small, fast, etc.Low cost, low power, small, fast, etc.

Reactive and real-timeReactive and real-time– Continually reacts to changes in the system’s Continually reacts to changes in the system’s

environmentenvironment– Must compute certain results in real-time Must compute certain results in real-time

without delaywithout delaySlide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction, 2000


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Characteristics of Embedded SystemsCharacteristics of Embedded Systems Application-specific functionality – specialized for one or one Application-specific functionality – specialized for one or one

class of applicationsclass of applications Deadline constrained operation – system may have to perform Deadline constrained operation – system may have to perform

its function(s) within specific time periods to achieve successful its function(s) within specific time periods to achieve successful resultsresults

Resource challenged – systems typically are configured with a Resource challenged – systems typically are configured with a modest set of resources to meet the performance objectivesmodest set of resources to meet the performance objectives

Power efficient – many systems are battery-powered and must Power efficient – many systems are battery-powered and must conserve power to maximize the usable life of the system.conserve power to maximize the usable life of the system.

Form factor – many systems are light weight and low volume to Form factor – many systems are light weight and low volume to be used as components in host systemsbe used as components in host systems

Manufacturable – usually small and inexpensive to manufacture Manufacturable – usually small and inexpensive to manufacture based on the size and low complexity of the hardware.based on the size and low complexity of the hardware.

Slide credit Y William, GWUSlide credit Y William, GWU


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Design with focus on ApplicationDesign with focus on Application

Slide credit – P Koopman, CMUSlide credit – P Koopman, CMU


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Design ConstraintsDesign Constraints



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Design ChallengesDesign Challenges Does it really work?Does it really work?

– Is the specification correct?Is the specification correct?– Does the implementation meet the spec?Does the implementation meet the spec?– How do we test for real-time characteristics?How do we test for real-time characteristics?– How do we test on real data?How do we test on real data?

How do we work on the system?How do we work on the system?– Observability, controllability?Observability, controllability?– What is our development platform?What is our development platform?


More importantly – optimising design More importantly – optimising design metrics!!metrics!!


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Design MetricsDesign Metrics• Common metricsCommon metrics

• Unit cost: Unit cost: the monetary cost of manufacturing each copy of the monetary cost of manufacturing each copy of the system, excluding NRE costthe system, excluding NRE cost

• NRE cost (Non-Recurring Engineering cost): NRE cost (Non-Recurring Engineering cost): The one-time monetary cost of designing the systemThe one-time monetary cost of designing the system

• Size: Size: the physical space required by the systemthe physical space required by the system

• Performance: Performance: the execution time or throughput of the systemthe execution time or throughput of the system

• Power: Power: the amount of power consumed by the systemthe amount of power consumed by the system

• Flexibility: Flexibility: the ability to change the functionality of the the ability to change the functionality of the system without incurring heavy NRE costsystem without incurring heavy NRE cost

Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software IntroductionSlide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction


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Design MetricsDesign Metrics

• Common metrics (continued)Common metrics (continued)• Time-to-prototype: Time-to-prototype: the time needed to build a working the time needed to build a working

version of the systemversion of the system

• Time-to-market: Time-to-market: the time required to develop a system to the time required to develop a system to the point that it can be released and sold to customersthe point that it can be released and sold to customers

• Maintainability: Maintainability: the ability to modify the system after its the ability to modify the system after its initial releaseinitial release

• Correctness, safety, many moreCorrectness, safety, many more

Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software IntroductionSlide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Introduction


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Trade-off in Design MetricsTrade-off in Design Metrics Expertise with both Expertise with both

software and hardwaresoftware and hardware is needed to optimize is needed to optimize design metricsdesign metrics– Not just a hardware or Not just a hardware or

software expert, as is software expert, as is commoncommon

– A designer must be A designer must be comfortable with various comfortable with various technologies in order to technologies in order to choose the best for a given choose the best for a given application and constraintsapplication and constraints

Slide credit Vahid/Givargis, Embedded Systems Design: Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software IntroductionA Unified Hardware/Software Introduction


SizePerformance

Power

NRE cost

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Time-to-market: a demanding design Time-to-market: a demanding design metricmetric

Time required to develop Time required to develop a product to the point it a product to the point it can be sold to customerscan be sold to customers

Market windowMarket window– Period during which the Period during which the

product would have highest product would have highest salessales

Average time-to-market Average time-to-market constraint is about 8 constraint is about 8 monthsmonths

Delays can be costlyDelays can be costlySlide credit Vahid/Givargis, Embedded Systems Design: A Slide credit Vahid/Givargis, Embedded Systems Design: A

Unified Hardware/Software IntroductionUnified Hardware/Software Introduction


Rev

enue

s ($)

Time (months)

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Losses due to delayed market Losses due to delayed market entryentry

Simplified revenue modelSimplified revenue model– Product life = 2W, peak at WProduct life = 2W, peak at W– Time of market entry defines Time of market entry defines

a triangle, representing a triangle, representing market penetrationmarket penetration

– Triangle area equals revenueTriangle area equals revenue Loss Loss

– The difference between the The difference between the on-time and delayed triangle on-time and delayed triangle areasareas

Slide credit Vahid/Givargis, Embedded Systems Slide credit Vahid/Givargis, Embedded Systems Design: A Unified Hardware/Software Design: A Unified Hardware/Software IntroductionIntroduction


On-time Delayedentry entry

Peak revenue

Peak revenue from delayed entry

Market rise Market fall

W 2W

Time

D

On-time

Delayed

Rev

enue

s ($)

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Other Design ConsiderationsOther Design Considerations DependabilityDependability

– Reliability: probability of system working Reliability: probability of system working correctly provided that it worked at time t=0correctly provided that it worked at time t=0

– Maintainability: probability of system working Maintainability: probability of system working correctly d time units after error occurred. correctly d time units after error occurred. [[Some systems require no maintenance Some systems require no maintenance throughout their operating lives (e.g. electric throughout their operating lives (e.g. electric kettles, computer keyboards), while some may kettles, computer keyboards), while some may need it such as mobile phones and airplane need it such as mobile phones and airplane flight control (software upgrade)flight control (software upgrade)]]


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Other Design ConsiderationsOther Design Considerations

DependabilityDependability– Availability: probability of system working at Availability: probability of system working at

time ttime t– SafetySafety– Security: in communicationSecurity: in communication

Basically, cBasically, critical applications have to operate ritical applications have to operate correctly at all time e.g. airplane flight control correctly at all time e.g. airplane flight control computer. This includes both computer. This includes both hardware and hardware and softwaresoftware aspects. aspects.


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Example of System FaultExample of System Fault

Slide credit B. PahamiSlide credit B. Pahami

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Other Design ConsiderationsOther Design Considerations

OOperating environmentperating environmentSome engine Electronic Control Units (ECUs) in Some engine Electronic Control Units (ECUs) in

cars are located under the bonnets. So they have cars are located under the bonnets. So they have to work at high temperature, as well as dusty to work at high temperature, as well as dusty and wet environment.and wet environment.

EMI (Electromagnetic Interference)EMI (Electromagnetic Interference)


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Real-Time ConsiderationReal-Time Consideration

Correct operation of real-time systems Correct operation of real-time systems means:means:– Working correctly (functionally correct)Working correctly (functionally correct)– Producing outputs Producing outputs in timein time!!

i.e. correct result at the right timei.e. correct result at the right time


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Hard Real-timeHard Real-time System designed to meet all deadlinesSystem designed to meet all deadlines A missed deadline is a design flawA missed deadline is a design flaw For examples: ABS brake, nuclear reactor For examples: ABS brake, nuclear reactor

monitoring systemmonitoring system System hardware (over) designed for worst-System hardware (over) designed for worst-

case performancecase performance System software rigorously testedSystem software rigorously tested Formal proofs used to guarantee timing Formal proofs used to guarantee timing

correctnesscorrectnessSlide credit – T GivargisSlide credit – T Givargis


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Firm Real-timeFirm Real-time System designed to meet all deadlines, but System designed to meet all deadlines, but

occasional missed deadline is allowedoccasional missed deadline is allowed– Sometimes statistically quantified (e.g. 5% Sometimes statistically quantified (e.g. 5%

misses)misses) For examples: multimedia systemsFor examples: multimedia systems System hardware designed for average case System hardware designed for average case

performanceperformance System software tested under average System software tested under average

(ideal) conditions(ideal) conditionsSlide credit – T GivargisSlide credit – T Givargis


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Soft Real-timeSoft Real-time System designed to meet as many deadlines System designed to meet as many deadlines

as possibleas possible– Best effort to complete within specified time, Best effort to complete within specified time,

but may be latebut may be late For examples: network switch or routerFor examples: network switch or router System hardware designed for average case System hardware designed for average case

performanceperformance System software tested under averaged System software tested under averaged

(ideal) conditions(ideal) conditionsSlide credit – T GivargisSlide credit – T Givargis



Deadlines• Deadline: maximum time before

a task must complete

• The profit associated with execution of a taskis after the deadline:– Hard deadline: negative– Firm deadline: 0 (either make

it or just don’t do it)– Soft deadline: decreasing

with time

timed

task

profit d

time

soft

firm

hardSlide taken from J.J Lukkien

Real-time Systems DeadlinesReal-time Systems Deadlines

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Levels of System DesignLevels of System Design


requirements

specification

architecture

componentdesign

systemintegration

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Traditional Embedded System Traditional Embedded System Design ApproachDesign Approach

Decide on the hardwareDecide on the hardware Give the chip to the software people.Give the chip to the software people. Software programmer must make software Software programmer must make software

‘fit’ on the chip and only use that ‘fit’ on the chip and only use that hardware’s capabilities.hardware’s capabilities.

Slide credit - Slide credit - W. McUmberW. McUmber,,MSUMSU


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Problems with Increased ComplexityProblems with Increased Complexity

Systems are becoming more and more Systems are becoming more and more complex.complex.

Harder to think about total design.Harder to think about total design. Harder to fix ‘bugs.’Harder to fix ‘bugs.’ Harder to maintain systems over time.Harder to maintain systems over time. Therefore, the traditional development Therefore, the traditional development

process has to change,process has to change,Slide credit - Slide credit - W. McUmberW. McUmber,,MSUMSU


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Design with Time ConstraintDesign with Time Constraint

In embedded electronics, the total design cycle In embedded electronics, the total design cycle must decrease.must decrease.

Historically, design for automotive electronic Historically, design for automotive electronic systems takes 3-5 years to develop.systems takes 3-5 years to develop.

Must be reduced to a 1-3 year development cycle.Must be reduced to a 1-3 year development cycle. Must still be reliable and safe.Must still be reliable and safe.B. Wilkie, R. Frank and J. Suchyta - Motorola Semiconductor Products Sectors, ‘Silicon or Software: The B. Wilkie, R. Frank and J. Suchyta - Motorola Semiconductor Products Sectors, ‘Silicon or Software: The

Foundation of Automotive Electronics’, IEEE Vehicular Tech., August 95.Foundation of Automotive Electronics’, IEEE Vehicular Tech., August 95.


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Possible Ways to DoPossible Ways to Do

Need to keep design process abstract for a Need to keep design process abstract for a longer period of time.longer period of time.

Decomposable hierarchy (object-oriented).Decomposable hierarchy (object-oriented). Reuse previous designs:Reuse previous designs:

– When a design changes, reuse similar sections.When a design changes, reuse similar sections.– Don’t throw away last year’s design and start from Don’t throw away last year’s design and start from

scratch!scratch! Automated verification systems.Automated verification systems.Slide credit - Slide credit - W. McUmberW. McUmber,,MSUMSU


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Levels of Embedded System DesignLevels of Embedded System Design

Slide credit – Ingo SanderSlide credit – Ingo Sander


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Design AbstractionDesign Abstraction



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Abstraction LevelsAbstraction Levels



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60




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Abstraction LevelAbstraction Level



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Hardware vs SoftwareHardware vs Software

Many functions can be done by Many functions can be done by softwaresoftware on on a general purpose microprocessor a general purpose microprocessor OROR by by hardwarehardware on an application specific ICs on an application specific ICs (ASICs)(ASICs)

For examples: game console graphic, For examples: game console graphic, PWM, PID controlPWM, PID control

Leads to Hardware/Software Co-design Leads to Hardware/Software Co-design conceptconcept


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Hardware or Software?Hardware or Software? Where to place functionality?Where to place functionality?

– ex: A Sort algorithmex: A Sort algorithm» Faster in hardware, but more expensive. Faster in hardware, but more expensive. » More flexible in software but slower.More flexible in software but slower.» Other examples?Other examples?

Must be able to explore these various trade-offs:Must be able to explore these various trade-offs:– Cost.Cost.– Speed.Speed.– Reliability.Reliability.– Form (size, weight, and power constraints.)Form (size, weight, and power constraints.)

Slide credit - Slide credit - W. McUmberW. McUmber,, MSU MSU


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Slide credit - Slide credit - Mike SchulteMike Schulte


EmbeddedApplication-Specific

Processors

EmbeddedDomain-Specific

Processors

General-Purpose Processors

FFT ProcessorsMPEG ProcessorsFIR Processors

Graphics ProcessorsDSP ProcessorsNetwork Processors

WorkstationsPersonal Computers

Pow

er/P

erfo

rman

ce

Programmability and Flexibility

65




66

Microcessor technologyMicrocessor technology



Processors vary in their customization for the problem at handProcessors vary in their customization for the problem at handtotal = 0for i = 1 to N loop total += M[i]end loop

General-purpose processor

Single-purpose processor

Application-specific processor

Desired functionality

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General-purpose processorsGeneral-purpose processors



Programmable device used in a variety of Programmable device used in a variety of applicationsapplications– Also known as “microprocessor”Also known as “microprocessor”

FeaturesFeatures– Program memoryProgram memory– General datapath with large register file and General datapath with large register file and

general ALUgeneral ALU User benefitsUser benefits

– Low time-to-market and NRE costsLow time-to-market and NRE costs– High flexibilityHigh flexibility

““Pentium” the most well-known, but Pentium” the most well-known, but there are hundreds of othersthere are hundreds of others

IR PC

Registerfile

GeneralALU

DatapathController

Program memory

Assembly code for:

total = 0 for i =1 to …

Control logic and

State register

Datamemory

68

Single-purpose processorsSingle-purpose processors



Digital circuit designed to execute exactly Digital circuit designed to execute exactly one programone program– a.k.a. coprocessor, accelerator or peripherala.k.a. coprocessor, accelerator or peripheral

FeaturesFeatures– Contains only the components needed to Contains only the components needed to

execute a single programexecute a single program– No program memoryNo program memory

BenefitsBenefits– FastFast– Low powerLow power– Small sizeSmall size

DatapathController

Control logic

State register

Datamemory

index

total

+

69

Application-specific processorsApplication-specific processors



Programmable processor optimized for a Programmable processor optimized for a particular class of applications having particular class of applications having common characteristicscommon characteristics– Compromise between general-purpose and Compromise between general-purpose and

single-purpose processorssingle-purpose processors FeaturesFeatures

– Program memoryProgram memory– Optimized datapathOptimized datapath– Special functional unitsSpecial functional units

BenefitsBenefits– Some flexibility, good performance, size and Some flexibility, good performance, size and

powerpower DSPDSP จดัอยูใ่นประเภทน้ีด้วยจดัอยูใ่นประเภทน้ีด้วย

IR PC

Registers

CustomALU

DatapathController

Program memory

Assembly code for:

total = 0 for i =1 to …

Control logic and

State register

Datamemory

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FPGA ArchitectureFPGA Architecture

FPGA layout with Configurable Logic Blocks (CLB) and I/O Blocks (IOB) FPGA layout with Configurable Logic Blocks (CLB) and I/O Blocks (IOB) (credit: Katz’s Contemporary Logic Design)(credit: Katz’s Contemporary Logic Design)


IOB IOB IOB IOB

CLB CLB

CLB CLB

IOB

IOB

IOB

IOB

Wiring Channels

Typical CLB (credit: www.wikipedia.com)

Programmable switch at wiring intersection (credit: www.wikipedia.com)

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Highly constrained products tend to use Highly constrained products tend to use application specific processorsapplication specific processors– Many mobile phones (power&size constrained) Many mobile phones (power&size constrained)

contain ARM chipscontain ARM chips– Hi-Fi (high performance&time constrained) Hi-Fi (high performance&time constrained)

contain DSP chipscontain DSP chips


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Software CostsSoftware Costs



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Disciplines Used in Embedded System Disciplines Used in Embedded System DesignDesign

Slide credit – R Gupta, UC IrvineSlide credit – R Gupta, UC Irvine


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Trends in Embedded SystemsTrends in Embedded Systems

Slide credit – R Gupta, UC IrvineSlide credit – R Gupta, UC Irvine


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Future Embedded SystemsFuture Embedded Systems



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Slide credit – P Koopman, CMUSlide credit – P Koopman, CMUIntroduction to Embedded SystemsIntroduction to Embedded Systems Setha Pan-ngum Setha Pan-ngum

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Observations on Future Embedded Observations on Future Embedded SystemsSystems

More complexity (people expect more More complexity (people expect more functions and higher performance from functions and higher performance from their electronic products)their electronic products)

This leads to more complex softwareThis leads to more complex software Which requires better design processWhich requires better design process More importantly, thorough testing for More importantly, thorough testing for

safety critical systems (diagnostics codes of safety critical systems (diagnostics codes of engine ECUs is half of its total software engine ECUs is half of its total software codes)codes)


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Research in Embedded SystemsResearch in Embedded Systems• Hardware – to improve performance (sensors and Hardware – to improve performance (sensors and

actuators), verification, etc.actuators), verification, etc.• Software – reusability, testing, verification, OS, etc.Software – reusability, testing, verification, OS, etc.• Network – higher connectivity between systems (e.g. Network – higher connectivity between systems (e.g.

smart homes link many systems together, standardised smart homes link many systems together, standardised protocols, etc.protocols, etc.

• Security – protection against attacksSecurity – protection against attacks• Design – improved methodology, more automation, Design – improved methodology, more automation,

formal verificationformal verification


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Introduction to Embedded Systems

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