Jaeyong Chung

System-on-Chips (SoC) Lab.

Incheon National University

Embedded System Design

Lecture 2

Introduction

What are embedded computing systems?

Characteristics of embedded systems

Challenges in embedded computing system design.

Design methodologies.

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What are embedded systems?

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Definition

Embedded computing system: any device that

includes an information processing system but is not

itself a general-purpose computer.

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Definition

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“Dortmund“ Definition: [Peter Marwedel]

Embedded systems are information processing systems

embedded into a larger product

Berkeley: [Edward A. Lee]:

Embedded software is software integrated with physical

processes. The technical problem is managing time and

concurrency in computational systems.

Cyber-Physical (cy-phy) Systems (CPS) are integrations of

computation with physical processes [Edward Lee, 2006].

Cyber-physical system (CPS) =

Embedded System (ES) + physical environment

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Cyber-Physical System

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CPS = ES + physical environment

Embedded systems ("computers inphysical environments")Embedded systems

("small computers")

Cyber-physical systems

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Cyber-Physical System

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Extreme view:

PhysicalCyber

Digital Controls Systems, ca. 1980

Cyber-Physical Systems, 2010+ !

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Internet of Things (IoT)

Embedded System + Internet Connectivity on Things

Computers are often not so smart because

Insufficient information on the environment

IoT may allow computers to perceive the world real-time

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Real-time model of the world

Applications

Application Area: Automotive Electronics

© P. Marwedel, 2011

[Based on slide by J.Engblom]

Functions by embedded processing:

ABS: Anti-lock braking systems

ESP: Electronic stability control

Airbags

Efficient automatic gearboxes

Theft prevention with smart keys

Blind-angle alert systems

... etc ...

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.

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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.

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BMW 850i, cont’d.

brake

sensor

brake

sensor

brake

sensor

brake

sensor

ABShydraulic

pump

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Application Area: Avionics

© P

. M

arw

edel, 2

011

Avionics

Flight control systems,

anti-collision systems,

pilot information systems,

power supply system,

flap control system,

entertainment system,

And many more

Dependability is of outmost importance

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More Application Areas

©Photos: P. Marwedel

Railroad

Waterways

Structural Safety

Sensors + data analysis

Taipeh 101

Bridge at Vancouver

Kilauea, Hawaii

Möhne lake dam

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Industrial Production Systems

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Chemical Installation

High-speed Bonder(SMD/PCB)

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Finger print sensors

Airport security systems

Access control

Smart cards

Dependability is of outmost importance

Authentication Systems

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Smart Home

© P. Marwedel

Zero energy building, generates as much energy as

it consumes

Provides safety and security

Supports owners

Provides maximum comfort

ambient assisted living

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Learning Thermometers

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Nest Lab

A home automation company

Founded by ex-apple engineers, Tony Fadell and Matt

Rogers, in 2010

Acquired by Google for $3.2 billion in cash

Learning Thermometers

Easy to use

Good design

벨브의신

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“아파트 ‘난방코딩’, 이런게 IoT 아닌가요?” –

Blotter.net

Medical Systems

For example:

Artificial eye: several

approaches, e.g.:

Camera attached to glasses;

computer worn at belt; output

directly connected to the

brain, “pioneering work by

William Dobelle”. Previously

at [www.dobelle.com]

Translation into sound;

claiming much better

resolution.

[http://www.seeingwithsound.c

om/etumble.htm]

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Smart Medicine

Diagnosis

Support of therapy

Evaluation

Risk analysis

Information about patients

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switch

power station

control

station

sensors and local control

Decentralized

Control

centralized control

long distance

communication

Local Process

control

Centralized control

and monitoring

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© DFG-

Forschergrup

pe 1511, TU

Dortmund,

Wietfeld,

Rehtanz et

al.

Smart Grid

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Smart Beer Glass

8-bit processor

Capacitive sensor for fluid

level

Inductive coil for RF ID activation &

power

CPU and reading coil in the table. Reports the level of fluid in the glass, alerts servers when close to empty

Contact less transmission of power and

readings

© Jakob Engblom

Integrates several technologies:

Radio transmissions

Sensor technology

Magnetic inductance for

power

Computer used for

calibration

Impossible without the computer

Meaningless without the

electronics

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More Application Areas

© Graphics: P. Marwedel, 2011

Telecommunication

Consumer electronics

Robotics

Public safety

Military systems

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Consumer Electronics

Simple control: front panel of microwave oven, etc.

Canon EOS 3 has three microprocessors.

32-bit RISC CPU runs autofocus and eye control systems.

Digital TV: programmable CPUs + hardwired logic for

video/audio decode, menus, etc.

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Head Mounted Display

Oculus VR

Founded by a HMD designer, Palmer Luckey

After E3 demo, the company announced a Kickstarter campaign

Within 4 hours of the announcement, raised $250,000 funding

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Robotics

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NASA’s Mars Sojourner Rover

Sony Aibo ERS-110 Robotic Dog

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Characteristics of embedded systems

Dependability

Efficiency

Real-time constraints

Reactive & hybrid systems

Dedicated systems

Security

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CPS/ES must be dependable,

Reliability R(t) = probability of system

working correctly provided that it was

working at t=0

Maintainability M(d) = probability of

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

Security: confidential and authentic

communication

Dependability

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Efficiency

© Graphics: Microsoft, P. Marwedel, M. Engel, 2011

CPS & ES must be efficient

Code-size efficient

(especially for microcontroller)

Run-time efficient

Cost efficient

Energy efficient

Small form factor

Small weight (light)

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Importance of Energy Efficiency

© Hugo De Man (IMEC) Philips, 2007

Efficient software design needed, otherwise, the price for software flexibility cannot be paid.

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CPS & ES Hardware

CPS & ES hardware is frequently used in a loop

(“hardware in a loop“):

Cyber-physical systems (!)

© Graphics: Microsoft, P. Marwedel, 2011

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Real-time Constraints

© Graphics: Microsoft

t

execute

CPS 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.

“A real-time constraint is called hard, if not meeting that

constraint could result in a catastrophe“ [Kopetz, 1997].

All other time-constraints are called soft.

A guaranteed system response has to be explained without

statistical arguments [Kopetz, 1997].

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Real-time Systems & CPS

CPS, ES and Real-Time Systems synonymous?

For some embedded systems, real-time behavior is less important

(smart phones)

For CPS, real-time behavior is essential, hence RTS CPS

CPS models also include a model of the physical system

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Reactive & Hybrid Systems

© Graphics: Microsoft, P. Marwedel, 2011

Typically, CPS are reactive systems:

“A reactive system is one which is in continual

interaction with environment and executes at a pace

determined by that environment“

[Bergé, 1995]

Behavior depends on input and current state.

automata model appropriate,

model of computable functions inappropriate.

Hybrid systems

(analog + digital parts).

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Dedicated Systems

© Graphics: P. Marwedel, 2011

Dedicated towards a certain application

Knowledge about behavior at design time can be

used to minimize resources and to maximize

robustness

Dedicated user interface

(no mouse, keyboard and screen)

Situation is slowly changing here: systems become

less dedicated

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Security

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Defending against

Cyber crime („Annual U.S. Cybercrime Costs Estimated

at $100 Billion; …[Wall Street Journal, 22.7.2013])

Cyber attacks

Cyber terrorism

Cyber war (Cyber-Pearl-Harbor

[Spiegel Online, 13.5.2013])

Connectivity increases threats

entire production chains can be affected

local islands provide some encapsulation, but contradict idea

of global connectedness

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Characteristics lead to corresponding challenges

© G

raphic

s: P

. M

arw

edel, 2

011

Challenges

Dependability

Energy Efficiency

Hardware properties, physical environment

Meeting real time requirements

Manufacturing Cost, Form factor, etc

Addressing any of these challenges add

a value to products

That value can be a game changer

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Dart: The world’s smallest Laptop Adaptor

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To be an ES expert

CS

Physics

EE

medicine, statistics, ME, biology

Knowledge from many areas must be available

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Design Methodologies/Flow

A procedure for designing a system.

Understanding your methodology helps you ensure

you didn’t skip anything.

Compilers, software engineering tools, computer-

aided design (CAD) tools, etc., can be used to:

help automate methodology steps;

keep track of the methodology itself.

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Traditional Design Flow

Start from some informal specification of functionality

and a set of constraints (time, power, cost, etc)

Generate a more formal specification of the

functionality based on some modeling concept (finite

state machine, data-flow, etc) using Matlab,

statecharts, C, C++, UML, VHDL, etc

Simulate the model to check the functionality. If

needed make adjustments

Choose an architecture (microprocessor, buses, etc)

such that the cost limits are satisfied and, you hope,

that time and power constraints will be fulfilled

Build a prototype and implement the system

Verify the system

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Traditional Design Flow (cont.)

If neither time nor power constraints are satisfied,

Go back to the architecture selection and choose another

architecture and start a new implementation

Or negotiate with the customer on the constraints

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Platform/Architecture Selection

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Platforms

(Mostly educational) Raspberry Pi, Aduino

System-on-chip

Processors

Microcontroller Architecture

ARM Cortex-M, Atmel AVR, AVR32, Intel 8051, etc

Microprocessor Architecture

FPGA

Microprocessors + FPGA

ASIC

IoT Enablers

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Bluetooth Smart (Low Energy)

Beacon (Background scan)

System-on-chips

smaller form factor

Lower power

Lower cost

Standard

These allow us to make

For example, a sensor swarm (i.e., many sensors)

https://www.youtube.com/watch?v=lniACfnHwVM

https://www.youtube.com/watch?v=uoOXRa8DXTM

IoT Hardware Platforms

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http://postscapes.com/internet-of-things-hardware

Tinyduino ($18) PanStamps ($19) RFduino (built-in BLE)

Summary

Embedded computers are all around us.

Many systems have complex embedded hardware and

software.

Embedded systems pose many design challenges:

design time, deadlines, power, etc.

Design methodologies help us manage the design

process.

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