Lecture by Prof Dr. Iram Baig (Dean Computer Software Department) University of Engineering and Technology Taxila

1. Prof. Dr. Muhammad Iram Baig
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2. What is an Embedded System?
 A physical system that employs computer control for a
specific purpose, rather than for general-purpose
computation
 Any device that includes a computer but is not itself a general-
purpose computer
 Hardware and Software, part of some larger systems and
expected to work without human intervention.
 Often the user of the device is not even aware that a
computer is present.
 Respond, monitor, control external environment using sensors &
actuators.
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3. A “short list” of embedded systems
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Anti-lock brakes
Auto-focus cameras
Automatic teller machines
Automatic toll systems
Automatic transmission
Avionic systems
Battery chargers
Camcorders
Cell phones
Cell-phone base stations
Cordless phones
Cruise control
Curbside check-in systems
Digital cameras
Disk drives
Electronic card readers
Electronic instruments
Electronic toys/games
Factory control
Fax machines
Fingerprint identifiers
Home security systems
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Modems
MPEG decoders
Network cards
Network switches/routers
On-board navigation
Pagers
Photocopiers
Point-of-sale systems
Portable video games
Printers
Satellite phones
Scanners
Smart ovens/dishwashers
Speech recognizers
Stereo systems
Teleconferencing systems
Televisions
Temperature controllers
Theft tracking systems
TV set-top boxes
VCR’s, DVD players
Video game consoles
Video phones
Washers and dryers
Life-support systems
Medical testing systems
And the list goes on and on
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4. Embedded System Applications
Aerospace
Navigation systems, automatic landing systems, flight
attitude controls, engine controls, space exploration
(e.g., the Mars Pathfinder).
Automotive
Fuel injection control, passenger environmental controls,
anti-lock braking systems, air bag controls, GPS
mapping.
Children's Toys
Nintendo's "Game Boy", Mattel's "My Interactive Pooh",
Tiger Electronic's "Furby".
Communications
Satellites; network routers, switches, hubs.
Home
Dishwashers, microwave ovens, VCRs, televisions,
stereos, fire/security alarm systems, lawn sprinkler
controls, thermostats, cameras, clock radios, answering
machines.
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5. Embedded System Applications
Industrial
Elevator controls, surveillance systems, robots.
Office
Automation
FAX machines, copiers, telephones, cash registers.
Medical
Imaging systems (e.g., XRAY, MRI, and ultrasound),
patient monitors, heart pacers.
Personal
Personal Digital Assistants (PDAs), pagers, cell phones,
wrist watches, video games, portable MP3 players, GPS.
Instrumentation
Data collection, oscilloscopes, signal generators, signal
analyzers, power supplies
Computer
Peripherals
Printers, scanners, keyboards, displays, modems, hard
disk drives, CD-ROM drives.
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7. Embedded Systems Hardware
Embedded systems hardware is used for processing input to
provide output in task specific fashion
Input
Interface
Information
Processing Systems
Output
Interface
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8. Processors
 Micro-processors and Microcontrollers
 Key Requirements:
 Energy Efficiency
 High Code Density
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Combined Size of all instruction
Characteristics of a particular instruction set
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9. Microprocessors
 CPU for computers
 No RAM, ROM, IO on CPU chip itself
 Example: Intel x86, Motorola 680x0
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CPU
DataBus
RAM
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ROM
I/O
Ports
Timers
Serial
Port
Address Bus
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10. Microcontrollers ?
 Basically microcontroller is a device which
integrates a number of the components of a
microprocessor system onto a single microchip.
 A Micro-controller combines onto the same
microchip.
 The CPU core
CPU
RAM
ROM
I/O
Timers
Serial
Port
 Memory
(both RAM and ROM)
 Parallel Digital I/Os
 other I/Os & more
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11. Components of a Micro-controller
 A Timer module to allow the micro-controller
to perform tasks for certain time periods
 A serial I/O port to allow data to flow between
the micro-controller and other devices such as
a PC or another micro-controller
 An ADC to allow the micro-controller to accept
analogue input data for processing
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12. Micro-controller
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13. Why Micro-controller?
 Low cost, small packaging
 Low power consumption
 Programmable, re-programmable
 Lots of I/O capabilities
 Easy integration with circuits
 For applications in which cost, power and space are
critical
 Single-purpose
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14. Architectures
Von Neuman
 Only one Memory holds data + instructions
 Data and Program share the same bus and the
same memory, and so must have the same width.
 CPU Registers:
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PC, IR and other general
purpose
 Bottleneck: Getting
instructions interferes with
accessing RAM
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15. Architectures
contd…
Harvard
 Separate program bus and data bus
 Can be different widths!
 Pipelining Easy
 Allows 2 simultaneous
memory Fetches
 Greater memory Bandwidth
 More predictable Bandwidth
 Most DSPs use Harvard Architecture for streaming data.
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16. Architectures
contd…
CISC - (Complex Instruction Set Computer)
 A large number of instructions each carrying
permutation of the same operation
 Instructions provide for complex operations
 Different instructions of different format
 Different instructions of different length
 Many Addressing modes
 Requires multiple cycles for execution
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17. Architectures
contd…
RISC- (Reduced Instruction Set Computer)
 Reduced set of Instructions for simple operations
 Pipeline Friendly
 Each instruction of fixed length
 Instructions that can be executed in a single cycle
 Large general purpose Register set
 Can contain data or addresses
 Load-store Architecture
 No Memory Access for data
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18. Architectures
RISC vs
contd…
CISC
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19. Architectures
contd…
 Super Scalar
 Multiple CPUs in a single Processor
 Processor decides at runtime about the instructions that
can be executed parallel. (Complex HW)
 Instructions will be executed in an order different from the
strictly sequential one with the restriction that the result
must be correct.
 Execution policies:
 1. In-order issue with in-order completion
 2. In-order issue with out-of-order completion
 3. Out-of-order issue with out-of-order completion
 Examples:
Intel’s Pentium, IBM Power2, AMD K5, MIPS R10K, HP PA8500,
Cyrix 6x86
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20. Architectures
contd…
VLIW (Very Large Instruction Word)
 Multiple CPUs in a single Processor
 Compiler decides about the instructions that can
be executed parallel and can be grouped in one
bundle (ILP, Instruction Level Parallelism)
 Examples:
i860 (dual mode: RISC and VLIW), TriMedia, SHARC,
Itanium, EPIC, ST200, StarCore, Transmeta Crusoe,
Xtensa
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21. CISC vs RISC vs SS vs VLIW
CISC
RISC
Superscalar
VLIW
Instruction
size
variable size
fixed size
fixed size
fixed size (but
large)
Instruction
format
variable
format
fixed format
fixed format
fixed format
Registers
few, some
special
many GP
GP and rename many, many
(RUU)
GP
Memory
reference
embedded in
many instr’s
load/store
load/store
load/store
Key Issues
decode
complexity
data
forwarding,
hazards
hardware
dependency
resolution
code
scheduling,
(compiler)
Instruction
flow
EX M WB
IF ID
EX M WB
IF ID
EX M WB
IF ID
EX M WB
IF ID
IF ID
EX M WB
IF ID
EX M WB
IF ID
EX M WB
IF ID
EX M WB
EX M WB
IF ID
EX M WB
EX M WB

22. Performance Comparison

23. Performance Comparison
contd…

24. Traditional Embedded Systems
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25. Components of Embedded Systems
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26. Simplified View of PIC MCUs

27. Few Examples of Embedded Systems
Product: Hunter Programmable Digital
Thermostat.
Microprocessor: 4-bit
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28. Product:Vendo V-MAX 720 vending
machine.
Microprocessor:
8-bit Motorola 68HC11.

29. Product: Sonicare Plus toothbrush.
Microprocessor: 8-bit Zilog Z8.

30. Product: Miele
dishwashers.
Microprocessor: 8bit Motorola
68HC05.

31. Product: NASA's
Mars Sojourner
Rover.
Microprocessor:
8-bit Intel 80C85.

32. Product: CoinCo USQ-712 coin
changer.
Microprocessor:
8-bit Motorola 68HC912.

33. Product: Garmin
StreetPilot GPS
Receiver.
Microprocessor:
16-bit.

34. Product: TIQIT
Computer’s
“Matchbox PC”.
Microprocessor: 32bit AMD Elan
SC410.

35. Product: Palm Vx
handheld.
Microprocessor:
32-bit Motorola
Dragonball EZ.

36. Product: Motorola
i1000plus iDEN MultiService Digital Phone.
Microprocessor:
Motorola 32-bit MCORE.

37. Product: Rio 800 MP3 Player.
Microprocessor: 32-bit RISC.

38. Product: RCA RC5400P DVD
player.
Microprocessor: 32-bit RISC.

39. Product: IBM
Research’s Linux
wrist watch
prototype.
Microprocessor:
32-bit ARM RISC.

40. Product: Sony Aibo
ERS-110 Robotic
Dog.
Microprocessor: 64bit MIPS RISC.

41. Embedded Automotive
More than 30% of the cost of a car is now in Electronics
90% of all innovations will be based on electronic systems
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43. Concluding Remarks
 Embedded computers are all around us.
 Many systems have complex embedded
hardware and software
 Embedded systems have pose many design
challenges: design time, deadlines, power, etc
 Design methodologies help us manage the
design process
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