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Embedded Systems Design: A Unified Hardware/Software Introduction
Introduction to embedded Systems
2Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Outline
• Embedded systems overview– What are they?
• Design challenge – optimizing design metrics• Technologies
– Processor technologies
– IC technologies
– Design technologies
3Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Embedded systems overview
• Computing systems are everywhere• Most of us think of “desktop” computers
– PC’s
– Laptops
– Mainframes
– Servers
• But there’s another type of computing system– Far more common...
4Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Embedded systems overview
• Embedded computing systems– Computing systems embedded within
electronic devices
– Hard to define. Nearly any computing system other than a desktop computer
– Billions of units produced yearly, versus millions of desktop units
– Perhaps 50 per household and per automobile
Computers are in here...
and here...
and even here...
Lots more of these, though they cost a lot
less each.
5Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
A “short list” of embedded systems
And the list goes on and on
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
6Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
2.08.02 CS4272 Lecture1 14
Automotive Electronics.• More than 30% of the car is now in electronics.
• 90% of innovations will be based on electronics.
7Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Automotive embedded systems
• Today’s high-end automobile may have 100 microprocessors:– 4-bit microcontroller checks seat belt;
– microcontrollers run dashboard devices;
– 16/32-bit microprocessor controls engine.
8Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
BMW 850i brake and stability control system
• Anti-lock brake system (ABS): pumps brakes to reduce skidding.
• Automatic stability control (ASC+T): controls engine to improve stability.
• ABS and ASC+T communicate.– ABS was introduced first---needed to interface to existing
ABS module.
9Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
BMW 850i, cont’d.
brake
sensor
brake
sensor
brake
sensor
brake
sensor
ABShydraulic
pump
10Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Some common characteristics of embedded systems
• Single-functioned– Executes a single program, repeatedly
• Tightly-constrained– Low cost, low power, small, fast, etc.
• Reactive and real-time– Continually reacts to changes in the system’s environment
– Must compute certain results in real-time without delay
11Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
• Supported by a wide array of processors• Cost sensitive• Uses real-time operating systems(RTOS)• Must operate under extreme environmental conditions• Fewer system resources• Object code stored in ROM• Software failure is much more severe
12Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Cost Sensitivity
• Usually embedded systems are manufactured in bulk
• Limited functionality(Size,Power,price)
• Powerful embedded processors
• Above requirements are found in cellular phones(DSP processors)
13Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Extreme Environmental conditions
• Runs everywhere anytime under any condition• It is not good practice to consider following aspects
during testing or packaging:• Heat budget• Slow down the clock• Change code(Optimize)
14Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Real-Time constraints
Time sensitive constraints(Soft real-time)• Due to some technical limitations task will take
longer time than the design goal. Instead of printing three pages per minute, two pages are printed.
Time critical(Hard real-time) Time critical task should take place within a time
frame, available between monitored or measured events. If the task is not completed before the next event arrives, the function controlled by that task fails.
15Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
An embedded system example -- a digital camera
Microcontroller
CCD preprocessor Pixel coprocessorA2D
D2A
JPEG codec
DMA controller
Memory controller ISA bus interface UART LCD ctrl
Display ctrl
Multiplier/Accum
Digital camera chip
lens
CCD
• Single-functioned -- always a digital camera• Tightly-constrained -- Low cost, low power, small, fast• Reactive and real-time -- only to a small extent
16Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Design challenge – optimizing design metrics
• Obvious design goal:– Construct an implementation with desired functionality
• Key design challenge:– Simultaneously optimize numerous design metrics
• Design metric– A measurable feature of a system’s implementation
– Optimizing design metrics is a key challenge
17Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Design challenge – optimizing design metrics
• Common metrics– Unit cost: the monetary cost of manufacturing each copy of the system,
excluding NRE cost
– NRE cost (Non-Recurring Engineering cost): The one-time monetary cost of designing the system
– Size: the physical space required by the system
– Performance: the execution time or throughput of the system
– Power: the amount of power consumed by the system
– Flexibility: the ability to change the functionality of the system without incurring heavy NRE cost
18Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Design challenge – optimizing design metrics
• Common metrics (continued)– Time-to-prototype: the time needed to build a working version of the
system
– Time-to-market: the time required to develop a system to the point that it can be released and sold to customers
– Maintainability: the ability to modify the system after its initial release
– Correctness, safety, many more
19Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Microprocessor varieties
• Microcontroller: includes I/O devices, on-board memory.
• Digital signal processor (DSP): microprocessor optimized for digital signal processing.
• Typical embedded word sizes: 8-bit, 16-bit, 32-bit.
20Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Application examples
• Simple control: front panel of microwave oven, etc.• Canon EOS 3 has three microprocessors.
– 32-bit RISC CPU runs autofocus and eye control systems.
• Analog TV: channel selection, etc.• Digital TV: programmable CPUs + hardwired logic.
21Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
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Embedded Systems Design: A Unified Hardware/Software Introduction
In the 21st Century, internet-enabled appliances will dominate the technology space - paving the way for electronic maintenance.
and beyond
Technology Overview
Decade Predominant Technology
’60s Mainframes
’70s Mini Computers
’80s Personal Computers
’90s Internet for people
2000 Internet for Devices
Source: IDC
e-VendingVending
Managementfrom the Desktop
23Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
We provide real-time interactivity between man and machines over the Net
Devices World Sdn BhdYour Embedded Internet Partner
Recognizing the potential of the Embedded Internet Space, we have pioneered a cutting edge e-Maintenance application complete with hardware and software solution.
DevicesWorld.net
An integrated e-Maintenance portal with comprehensive software solutions for various industries.
Internet Access Devices
A comprehensive range of hardware to Internet-enable your legacy appliances. You have a choice of wired or wireless Internet connectivity.
e-VendingVending
Managementfrom the Desktop
24Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Internet
Stock Level Report
Machine Status Report
Dispatch Activity Log
Vending Activity Log
DevicesWorld.net Server
Operator’s Office
Internet
Automatic Alerts !
Pager
Phone
e-VendingVending
Managementfrom the Desktop
InternetGateway
25Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Cold Drink Vendor Snack Food Vendor Hot Drink Vendor
InternetGateway SlaveSlave
Internet
Tel
ep
ho
ne
Lin
e
GSM
One Gateway
16 Machines 1000m Apart
DevicesWorld.net
e-VendingVending
Managementfrom the Desktop
26Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
InternetGateway
Built-in Modem
5 Digital Inputs
5 Analogue Inputs
2 Digital Outputs
SlavePlug & Play
5 Digital Inputs
5 Analogue Inputs
2 Digital Outputs
Hardware Featurese-Vending
Event - driven Dialup
Automatic Health Check
On Demand Connection
Password Protection
Automatic Configuration
Local Data Logging
Data Encryption
27Embedded Systems Design: A Unified Hardware/Software Introduction, (c) 2000 Vahid/Givargis
Summary
• Embedded systems are everywhere
• Key challenge: optimization of design metrics– Design metrics compete with one another
• A unified view of hardware and software is necessary to improve productivity
• Three key technologies– Processor: general-purpose, application-specific, single-purpose
– IC: Full-custom, semi-custom, PLD
– Design: Compilation/synthesis, libraries/IP, test/verification