Embedded Systems and
Software
http://www.liacs.nl/~cserc/EMBSYST/ESSOFIA/2010
Lecturers: Ed F. Deprettere (edd@liacs.nl)
Todor Stefanov (stefanov@liacs.nl)
Hristo Nikolov (nikolov@liacs.nl)
Leiden Embedded Research Center (LERC)
Leiden Institute of Advanced Computer Science (LIACS)
Leiden University, The Netherlands
Course Organization:

Class Lectures and Discussions
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Goal: To introduce students to state-of-the-art methods, techniques,
and tools to design, program, implement, and use Embedded
Multiprocessor Systems-on-Chip (MPSoC).
Format:
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Oral presentations supported by PowerPoint slides. The slides will be
available on the web page after each lecture.
Discussions on relevant scientific journal/conference papers.
Hands-on tutorials with practical assignments
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Structure
The DAEDALUS framework is used to design and prototype a
relatively simple MPSoC
Independent study of scientific journal/conference papers
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Read and study papers on topics related to the course material
Presentation on the topic under study
2
Course Organization:
Grading
 There is NO traditional written exam
 The final grade is a combination of grades for
 Presentation on a given topic related to the course
material (40%)
 Performance during the hands-on sessions (40%)
 Pro-active attitude during lectures and paper discussions
(20%)
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Course Literature and Material
 Some reference books
 "Embedded System Design" by Peter Marwedel,
1st edition, Kluwer Academic Publishers: Hardbound, October 2003, 258 pp.
ISBN-10 1-4020-7690-8; ISBN-13 978-1-4020-7690-9 2nd edition, Springer:
Paperback, 2006, 258 pp. ISBN-10 0-387-29237-3; ISBN-13 978-0-387-29237-3
2)
 "Embedded System Design: Modeling, Synthesis and Verification" by Daniel
Gajski, Samar Abdi, Andreas Gerstlauer, and Gunar Schirner,
Springer, 2009, XXVI, 358 p. 185 illus., Hardcover ISBN: 978-1-4419-0503-1
 "Embedded System Design: A Unified Hardware/Software Introduction" by
Frank Vahid and Tony Givargis,
John Wiley & Sons; ISBN: 0471386782. Copyright (c) 2002.
 "Embedded Multiprocessors: Scheduling and Synchronization" by
Sundararajan Sriram, Shuvra S. Bhattacharyya, (Marcel Dekker)
 “Computers as Component, Principles of Embedded Computer Systems
Design” by Wayne Wolf, (Morgan Kaufman Publishers)
http://www.ee.edu/~wolf/embedded-book/about.html
 The slides contain (copyright) material of Peter Marwedel, Lothar
Thiele, Wayne Wolf, Daniel Gajski, Shuvra Bhattacharyya, Andy
Pimentel, Edward Lee, Stephan Edwards and from the above books
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Contents of Course

Introduction to Embedded Systems

Embedded Systems Components

Embedded Systems Specification and Modeling

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Models of Computation
Specification Languages
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Basic concepts, methods, techniques, and tools for design of
Embedded Systems

The DAEDALUS framework for Embedded MPSoC design
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Automatic parallelization of streaming media applications (KPNgen)
System-level modelling and simulations for DSE (Sesame)
System-level synthesis in a “plug-and-play” fashion (ESPAM)
Case Studies
Other System-level design frameworks for MPSoCs

System on Chip Environment from the UC Irvine, SystemCoDesigner from the
University of Erlangen, Metropolis from the UC Berkeley, Koski from the
University of Tampere, PeaCE/HOPES from the Seoul National University, …
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Introduction to
Embedded Systems and Software
Outline
 What is Embedded System?
 Examples
 Characteristics of Embedded Systems
 Comparison
 Embedded Systems vs. General Purpose Systems
 Trends in Embedded Systems
 Embedded Systems Design
 Future of Embedded Systems
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What is Embedded Systems?
Many Definitions exist:
[Peter Marwedel, TU Dortmund]
Embedded Systems = Information processing systems
embedded into a larger product
[Edward A. Lee, UC Berkeley]
Embedded Software = Software integrated with physical*
processes. The technical problem is managing time and
concurrency in computational systems.
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Yet Another Definition …
Embedded Systems = Information processing systems that
are:
• application domain specific (not general purpose)
• tightly coupled to their environment
Examples of application domains: automotive electronics,
avionics, multimedia, consumer electronics, etc.
Environment: type and properties of input/output information.
Tightly coupled: the environment dictates what the system’s
response behavior must be. (“ES cannot synchronize with
environment”)Embedded Systems and Software by Todor Stefanov 2010
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Embedded Systems
What they do:
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Sense environment
(input signals)
Process input
information
Respond in realtime (output signals)
In Embedded Systems time matters:
NOT in the sense that information processing should be always very fast
BUT in the sense that information processing should be:
determinate and time predictable
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Consumer Electronics

Examples:
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

Audio (MP3, …)
Video (digital camera, …)
Home electronics (washing machine, microwave cooker/oven, …)
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Automotive Electronics

Functions by embedded processing:
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



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
Multiple Networks

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ABS: Anti-lock braking systems
ESP: Electronic stability control
Efficient automatic gearboxes
Theft prevention with smart keys
Blind-angle alert systems
Airbags
... etc ...
Body, engine,
media, safety
Multiple Processors


Up to 100
NetworkedEmbedded
togehter
Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Avionics
 Flight control systems,
 Anti-collision systems,
 Pilot information systems,
 Power supply system,
 Flap control system,
 Entertainment system,
 …
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Telecommunication
 Information systems
 Wireless communication
 Mobile phone
 Wireless LAN
 Closed systems for police,
ambulance, rescue staff
 Geo-positioning systems
 Navigation
 etc
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Medical Systems
 For example
 Artificial Eye
 Camera is attached to glasses
 Computer is worn on belt
 Output directly connected to the brain
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Authentication Systems

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Finger print sensors
Airport security systems
Smartpen®
Access control
Smart cards
….
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Industrial Production Systems
High-speed
bonder
(SMD/PCB)
Chemical Installation
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Robotics
NASA's Mars
Sojourner Rover
Sony Aibo ERS-110
Robotic Dog
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Communicating ES
Sensor Networks (civil engineering, buildings,
environmental monitoring, traffic, etc.)
Embedded Systems and Software by Todor Stefanov 2010
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Examples of Embedded Systems:
Very Large Distributed ES
Distributed Hierarchical Radio Telescope
LOFAR/SKA
Station contains:
- 100 LF antennas
- 100 HF compound
antennas
350 km
Inner core contains:
- supercomputer
Embedded Systems and Software by Todor Stefanov 2010
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Embedded Systems are Everywhere:
Smart Beer Glass
Capacitive sensor
for fluid level
 Integrates several
technologies:
8-bit processor
Contact less
transmission
of power and
readings

Radio transmissions

Sensor technology

Magnetic inductance for
power

Computer used for
calibration
 Impossible without the
computer
Inductive coil for
RF
ID activation &
 Meaningless without the
power
electronics
© Jakob Engblom
CPU and reading coil in the table.
Reports the level of fluid in the glass,
alerts waiters when close to empty
Embedded Systems and Software by Todor Stefanov 2010
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Characteristics of Embedded Systems (1)
 Must be dependable
 Reliability: R(t) = probability of a system working correctly




provided that it was working at t = 0
Maintainability: M(d) = probability of a system working correctly
d time units after error occurred
Availability: A(t) = probability of system working at time t
Safety: no harm to be caused by failing system
Security: confidential and authentic communication
-Even perfectly designed systems can fail if the assumptions
about the workload and possible errors turn out to be wrong.
-Making the system dependable must not be an after-thought,
it must be considered from the very beginning.
Embedded Systems and Software by Todor Stefanov 2010
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Characteristics of Embedded Systems (2)
 Must be efficient
 Energy efficient
 Many ES are mobile systems powered by batteries
 Customers expect long run-times from batteries but
 Battery technology improves at a very slow rate
 Code-size efficient (especially for systems on a chip)

Typically there are no hard discs or huge memories to store code
 Run-time efficient
 Meet time constraints with least amount of HW resources and
energy – only necessary HW should be present working at as low as
possible Vdd and fclk
 Weight efficient (especially for portable ES)
 Cost efficient (especially for high-volume ES)
Embedded Systems and Software by Todor Stefanov 2010
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Characteristics of Embedded Systems (3)
 Many ES must meet real-time constraints
 A real-time system must react to stimuli from the controlled
object (or the operator) within the time interval dictated by the
environment.
 For real-time systems, right answers arriving too late (or even too
early) are wrong.
“A real-time constraint is called hard, if not meeting that
constraint
result inare
a catastrophe“
[Kopetz, 1997].
 All other could
time-constraints
called soft.
 A guaranteed system response has to be explained without
statistical arguments.
Embedded Systems and Software by Todor Stefanov 2010
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Characteristics of Embedded Systems (4)
 Frequently, ES are connected to physical environment
through sensors and actuators.
 Hybrid Systems, i.e., composed of analog and digital parts
 Typically, ES are reactive systems
“A reactive system is one which is in continual
interaction with is environment and executes at a pace
determined
by that environment“
[Bergé,
 Behavior depends
on input and current
state.1995].
 automata model appropriate
Embedded Systems and Software by Todor Stefanov 2010
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Characteristics of Embedded Systems (5)
 All ES are dedicated systems
 Dedicated towards a certain application:
Knowledge about the behavior at design time can be used to
minimize resources and to maximize robustness
 Dedicated user interface:
No mice, no large keyboards and monitors
Not every ES has all of the above characteristics, thus
We can define the term “Embedded System” as follows:
Information processing systems having most of the
above characteristics are called embedded systems.
Embedded Systems and Software by Todor Stefanov 2010
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Comparison
 Embedded Systems
 Execute few applications
that are known at designtime
 Non programmable by the
end user
 Fixed run-time
requirements (additional
computing power not
useful)
 Important criteria
 Cost
 General Purpose Systems
 Execute broad class of
applications
 Programmable by the end
user
 Faster is better
 Important criteria
 Cost
 Average speed
 Power consumption
Embedded Systems and Software by Todor Stefanov 2010
 Predictability
 …
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Trends in Embedded Systems
 In the past Embedded Systems were called Embedded
(micro-)Controllers
 They appeared typically in control dominated
applications:
 Traffic lights control
 Elevators control
 Washing machines and dishwashers
 …
 They were implemented using a single μProcessor or
dedicated HW (sequential circuit)
All this is rapidly changing nowadays.
How And Why?
Embedded Systems and Software by Todor Stefanov 2010
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Trends in Embedded Systems:
Towards Multi-Processor Systems
Complexity of ES is increasing, thus
 A single uProcessor is sufficient for some consumer
products
 Application performance demands relatively low
 For other systems – such as cars and aircrafts – a
network of processors is needed
 Due to performance requirements
 Due to safety requirements (a single failed component
should not cause total system failure)
 For some systems – such as mobile devices – a
network of heterogeneous processors is needed
Embedded Systems and Software by Todor Stefanov 2010
 Due to run-time efficiency requirements
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Trends in Embedded Systems:
Higher Degree of Integration
Moore’s Law: the number of transistors that can be placed
on a chip has doubled approximately every two years
 Microprocessor, microcontroller
 System-on-Chip (SoC)
P
CP
 Processor + memory + I/O-units + communication structure
 Multi-processor System on a Chip (MPSoC)
 Processor – Co-processor
TM
MIPS
 (Heterogeneous) Multi-processor
 Network on Chip
Embedded Systems and Software by Todor Stefanov 2010
 Identical tiles
Mem
CP1
CP2
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Trends in Embedded Systems:
Software Increasing (amount and complexity)
Implementing ES in specialized HW brings lack of flexibility
(changing standards) and very expensive masks, thus
 Most of the functionality will be implemented in software
 On the average, a human
“touches” about 50 to 100
micro-processors per day
 Average car has
15 micro-processors,
luxurious one ~ 60!
 Exponential increase in
software complexity
Embedded Systems and Software by Todor Stefanov 2010
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Embedded Systems Design (1)
Embedded Systems Design is NOT just a special case of
either hardware (Computer/Electrical Engineering) or
software (SoftwareEngineering/Computer Scence)
design.
 An embedded system performs computation that is
subject to physical constraints, i.e., interaction with a
physical environment and execution on a physical
(implementation) platform
 interaction: deadlines, throughput, jitter
 execution: available resources, power, failure rates
 It has functional requirements (expected services),
and it has extra-functional requirements
Embedded Systems and Software by Todor Stefanov 2010
(performance/cost,
robustness, etc.)
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Embedded Systems Design (2)
 Computer Science provides (software) functionality
for Instruction Set Architectures (ISA) which are
characterized by
 Instruction set
 Organization (program counter, register file, memory)
 Both independent of any logical implementation and
physical realization
 Computer/Electrical Engineering deals with
 Logical implementation
 Physical realization
 Embedded Systems design discipline needs to
combine these two approaches, because extrafunctional behavior (such as timing, cost, power,
robustness, etc.) is a crucial issue
 when there are real-time constraints imposed by the
environment
Embedded Systems and Software by Todor Stefanov 2010
 when to predict
extra-functional behavior using abstract 33
models that cannot be well specified if the relation between
Future of Embedded Systems
 Embedded Systems are everywhere
 Embedded Systems market will be much larger than the
market of PC-like systems
 Post-PC era in which information processing is more and
more moving away from just PCs to embedded systems
 Embedded Systems provide the basic technology for
Ubiquitous/Pervasive computing:
 Model of human-computer interaction in which information
processing has been thoroughly integrated into everyday
objects and activities
 Key goals is to make information available anytime,
anywhere
 Building Ambient Intelligence into our environment
Embedded Systems and Software by Todor Stefanov 2010
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The future is embedded,
embedded is the future
Embedded Systems and Software by Todor Stefanov 2010
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