An embedded system is a special-purpose computer system, which is completely encapsulated by the device it controls. An embedded system has specific requirements and performs pre-defined tasks, unlike a general-purpose personal computer.
An embedded system is a programmed hardware device. A programmable hardware chip is the 'raw material' and it is programmed with particular applications. This is to be understood in comparison to older systems with full functional hardware or systems with general purpose hardware and externally loaded software. Embedded systems are a combination of hardware and software which facilitates mass production and variety of application
A combination of computer hardware and software, and perhaps additional mechanical or other parts, designed to perform a dedicated function.
In some cases, embedded systems are part of a larger system or product, as in the case of an antilock braking system in a car.
v EMBEDDED SYSTEM is a combination of SOFTWARE and HARDWARE.
v An Embedded system is a system, that has a computing device embedded into it.
These are the controllers, processors, arrays or other hardware using dedicated (embedded) logic or programming (code) called “firmware” or a “microkernel”
Embedded systems are designed around a µC which integrates Memory & Peripherals
Embedded systems: What are they?
A special purpose computer built into a larger device
• ‘Special-purpose’
Embedded systems have a (more or less) well-defined purpose Contrast with: general purpose computers (PCs etc)
• ‘Built into a larger device’
Embedded systems are (usually) part of a larger device, augmenting its capabilities
WHY EMBEDDED SYSTEMS
It is EMBEDDED because the Micro Controller is ‘inside’ some other system.
For Example a Micro Controller is ‘EMBEDDED’ into your TV, car, or appliance
The consumer need not think about how to make it perform or process
§ Avoids lots of Electronics Components
§ Built in rich Features
§ Reduces the cost, space
§ Less Down Time for Maintenance
§ Probability of Failure is reduced
§ Easy interface with Computers
CHARACTERISTICS OF AN EMBEDDED SYSTEM
· Sophisticated functionality
· Real-Time Operation
· Low Manufacturing Cost
· Low Power Consumption
· Eliminates Necessity of Complex Circuitry
· Smarter Products
· Smaller Size
· User Friendly
· State of the Art Technology
Four General Embedded Systems Types
General Computing
• Applications similar to desktop computing, but in an embedded package
• Video games, set- top boxes, wearable computers, automatic tellers
Control Systems
• Closed- loop feedback control of real- time system
• Vehicle engines, chemical processes, nuclear power, flight control
Signal Processing
• Computations involving large data streams
• Radar, Sonar, video compression
Communication & Networking
• Switching and information transmission
• Telephone system, Internet
FEATURES OF AN EMBEDDED SYSTEM
Real-Time Operation
• Reactive: computations must occur in response to external events
• Correctness is partially a function of time
Small Size, Low Weight
• Hand- held electronics and Transportation applications -- weight costs money
Low Power
• Battery power for 8+ hours (laptops often last only 2 hours)
Harsh environment
• Heat, vibration, shock, power fluctuations, RF interference, lightning, corrosion
Safety- critical operation
• Must function correctly and Must not function in correctly
Extreme cost sensitivity
EMBEDDED SYSTEMS COMPONENTS
Ø MICRO CONTROLLERS (µC)
Ø MICRO PROCESSORS (µP)
Ø DIGITAL SIGNAL CONTROLLERS (DSC)
Ø DIGITAL SIGNAL PROCESSORS (DSP)
Ø BUSSES (Data, Address, Input/output)
Ø SYSTEM CLOCK - Steps µC / µP Through Each Instruction
Ø READ ONLY MEMORY (ROM): Permanently Loaded With Instructions (FIRMWARE)
Ø RANDOM ACCESS MEMORY (RAM)
Ø STORES DATA IN PROCESSING / SHARES DATA WITH EXTERNAL PARTNERS
Ø REAL TIME CLOCK (RTC)
Ø COMMUNICATIONS CIRCUITRY - Ethernet Port, Printer Port, Communications Port (RS232c, RS485, RS422, IEEE488)
EXAMPLES OF EMBEDDED SYSTEMS
· Automatic Teller Machines or ATM's & Bank Vaults
· Automotive & Automobile Engine Management systems: Electronic Dashboards, ABS brakes, transmission controls.
· Blue Tooth enabled Network Synchronization Applications
· Control Systems (Manufacturing, Cryogenics, Electric Power)
· Controls for Digital Equipment: CD Players, TV Remote, Programmable Sprinklers, Household Appliances, etc.
· Computer motherboards (BIOS chips, RTCs)
· Global Positioning and Navigation Systems
· Household Appliances
· Medical instrument’s controls - CT scanners, MRI Scanners, ECG, Pacemakers and implanted pumps, implanted heart monitors, etc.
· Supervisory Control and Data Acquisition (SCADA) systems
· Telecommunications (Private Branch Exchanges, Custom Premises Equipment)
EMBEDDED - DESIGN METHODOLOGIES
ü A procedure for designing a system
ü Understanding your methodology helps you ensure you didn’t skip anything.
ü Compilers, software engineering tools, computer-aided design (CAD) tools, etc., can be used to:
· help automate methodology steps;
· keep track of the methodology itself.
EMBEDDED – DESIGN GOALS
· Performance.
· Overall speed, deadlines.
· Functionality and user interface.
· Manufacturing cost.
· Power consumption.
· Other requirements (physical size, etc.)
LEVELS OF ABSTRACTION – STEP BY STEP DEVELOPMENT OF EMBEDDED SYSTEM
REQUIREMENTS
SPECIFICATION
ARCHITECTURE
COMPONENT
SYSTEM
TYPICAL EMBEDDED SYSTEM HARDWARE
• COMMERCIAL OFF-THE-SHELF COMPONENTS (COTS)
e.g. wireless radios, sensors, I/O devices, –Cheap
• APPLICATION-SPECIFIC ICS (ASICS)
ICs tailored to meet application needs, Good performance for their intended task(s), Original Ess were ASICs only
• DOMAIN-SPECIFIC PROCESSORS
· DSPs
· Microcontrollers
· Digital Signal Controllers
· Microprocessors
EMBEDDED SYSTEMS - EARLY HISTORY
• Late 1940’s: MIT Whirlwind computer was designed for real-time operations.
– Originally designed to control an aircraft simulator.
• First microprocessor was Intel 4004 in early 1970’s.
• HP-35 calculator used several chips to implement a microprocessor in 1972.
• Automobiles used microprocessor - based engine controllers starting in 1970’s.
– Control fuel/air mixture, engine timing, etc.
– Multiple modes of operation: warm-up, cruise, hill climbing, etc.
– Provides lower emissions, better fuel efficiency.
EMBEDDED SYSTEMS
v MICROCONTROLLERS
· Atmel, Microchip – PIC, Maxim, Motorola
v DIGITAL SIGNAL CONTROLLERS
· Microchip – dsPIC, Texas Instruments
v DSP & RTOS
· Analog Devices, Texas Instruments
v VLSI
· Altera, Cypress, Cirrus Logic, Xilinx
MICROCONTROLLERS
• Microcontroller is a highly integrated chip that contains all the components comprising a controller.
• Typically, this includes a CPU, RAM, some form of ROM, I/O ports, and timers. A Microcontroller is designed for a very specific task – to control a particular system.
• As a result, the parts can be simplified and reduced, which cuts down on production costs
DIGITAL SIGNAL CONTROLLER
• The Digital Signal Controller (DSC) is a powerful 16-bit (data) modified Harvard RISC machine that combines the control advantages of a high performance 16-bit Microcontroller (MCU) with the high computation speed of a fully implemented digital signal processor (DSP) to produce a tightly coupled single-chip single-instruction stream solution for embedded systems design.
DSP
• Specialized digital microprocessor used to efficiently and rapidly perform calculations on digitized signals that were originally analog in form (eg voice)
• The big advantage of DSP lies in the programmability of the processor, allowing parameters to be easily changed
VLSI
• Very large-scale integration, the process of placing thousands (or hundreds of thousands) of electronic components on a single chip.
• Nearly all modern chips employ VLSI architectures, or ULSI (ultra large scale integration)
TYPES OF MICRO CONTROLLER
More than 140 Types of Micro Controllers Available
Some of the examples are
• Microchip – PIC, dsPIC, rfPIC
• Atmel – AVR, ARM, 89cxx
• Analog Devices
• Texas Instruments
• ST Microcontrollers
• Zilog, Cypress, Maxim, Dallas, Motorola, etc.,
EMBEDDED SYSTEMS IN TODAY’S WORLD
SIGNAL PROCESSING SYSTEMS -
Real-Time Video, Set-top Boxes, DVD Players, Medical Equipment, Residential Gateways
DISTRIBUTED CONTROL -
Network Routers, Switches, Firewalls, Mass Transit Systems, Elevators
SMALL SYSTEMS -
Mobile Phones, Pagers, Home Appliances, Toys, Smart Cards, MP3 players, PDAs, Digital Cameras, Sensors, Smart Badges
BENEFITS OF EMBEDDED CONTROL DESIGN
• Eliminates necessity of complex circuitry
• Smarter products
• Smaller size
• Lower cost
• User friendly
• State of the art technology
FUTURE OF EMBEDDED CONTROL
• Intelligent products are used everyday - Mobile Phones, Printers, Washing Machines, Microwave Ovens, Water Purifier, Air Conditioners etc.
• New generation Embedded Control will include Internet connectivity, RF controls & Blue Tooth.
THE JOB OPPORTUNITIES IN THE AREAS OF
• Hardware Design Engineer
• Software Design Engineer
• Device Driver Developer
• Kernel Developer
• Network Engineer
• RTOS Programmer
• Software Engineer in Research & Development
COMPANIES ARE WORKING ON EMBEDDED SYSTEMS AND APPLICATIONS
• AXES technologies
• CG Smith
• Converge Labs
• Future Software
• IBM
• LUCENT
• MASCON
• Sundaram Telematics
• Visteon
• WIPRO
• TCS
• Infosys
• Robert Bosch
• Kshema Technologies
and so on
NEW TRENDS IN EMBEDDED SYSTEM H/W
• Systems-on-chip –Usual (or desired) specs:
• 32-bit RISC CPU
• Built-in interfaces to RAM and ROM
• Built-in DMA, interrupt and timing controllers
• Built-in interfaces to disk or flash memory
• Built-in Ethernet/802.11 interfaces
• Built-in LCD/CRT interfaces –New SOCs appearing almost every week!
• Examples – Intel StrongARM SA-1110, Motorola PowerPC MPC823e
– NEC VR4181
– Many, many more
EMBEDDED SOFTWARE PROPERTIES
• Timeliness
• Concurrency
• Liveness
• Interfaces
• Heterogeneity
• Reactivity
TIMELINESS
• Time: systematically removed from theories of computation
• RTOSes often reduce the characterization of a task to a single number (its priority)
• But: computation does take time
– However, even with infinitely fast computers, time would still have to be dealt with
• Physical processes evolve over time
• Need to find abstractions that regain control of time!
CONCURRENCY
• In the physical world, multiple things happen at once
• Challenge: reconcile sequentially of software with the concurrency of the real world
– Classic approaches (semaphores, monitors etc) provide good foundation
• But: potentially insufficient
– One approach: compile concurrency away (Estrel)
• Estrel: synchronous/reactive language
– FSM based, deterministic behavior
• Pros: Higly reliable programs
• Cons: Too static for some systems
– Middle ground is needed
LIVENESS
• Programs must not terminate
– Unlike the traditional Turing model of computation, halting is undesirable
–Deadlock is an absolute ‘no- no’
• Correctness isn’t just about getting the right final answer
– Must consider things like timing, power consumption, fault recovery, security and robustness
REACTIVITY
• Interactive systems:
– react at their own speed (or the speed of the controlling human)
• Transformational systems
– Transform a data input to a data output (e.g. matrix multiplication)
• Reactive systems
– react continuously with environment, at the same speed
– Must adapt to changing conditions
• Resources and demands may change frequently
– Real-time constraints
– Safety-critical
• Fault-tolerance can be a major issue
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