EmbeddedSystems - Aaltoose/embedded/T-106.5300_EmbeddedSystems_Lecture-1_24.01.2008_OSe.pdfJan 24,...

TEKNILLINEN KORKEAKOULUHELSINKI UNIVERSITY OF TECHNOLOGY

olli.seppala @ tkk.fi 1

Embedded SystemsT-106.5300

(5cr.), Spring 2008Olli Seppälä, Jaakko Ala-Paavola

January 24, 2008



What is an embedded system?



A matter of resources

200GB vs 32KB2GB vs 2KB

3GHz vs 4MHz100W vs 100mW

s vs ms vs µs



A fitness test on your wrist?



The structure of the ANN in the Polar Fitness Test™

Pers

onal

dat

a Polar OwnIndex™H

R a

nd H

RV Predicted VO2max

InputHidden layer

- nonlinear operation- linear operation



A fitness test on your wrist?

• 8-bit microprocessor• neural network• other software



Now



Course Basics 1/2Objective: To learn to design and to implement software for embedded systems given some hardware interfaces. The course discusses the implementation techniques of embedded systems, hardware issues, system testing and verification, fault tolerance and different paradigms for specification and design.

•Prerequisites: – T-106.3100 - Intermediate Course in Programming T2 (the C language) (5 cr)/

or T-106.3101 - Intermediate Course in Programming T2 (6 cr) or T-106.237 - Intermediate Course in Programming 2 (3 cr)or AS-0.1101/AS-0.101 or some other course on programming with C

– T-106.4150 - Operating Systems and Concurrent Programming (5 cr)T-106.4155 - Operating Systems (5 cr)T-106.430 - Operating Systems (3 ocr)

•Recommended courses:– T-106.4100/T-106.410 Design and Analysis of Algorithms– T-61.123 Computer Architecture– T-61.124 Computer Architecture Assignment Work– S-88.110 (digital systems)



Course Basics 2/2• To pass the course: Examination, possible homeworks and an

exercise project (developing the control software for a computercontrolled car) in a group of 3 persons. Hardware gurus can ask the lecturer about custom projects.

• Lectures: Thursdays 14-16 in lecture hall T1

• Instructors:olli.seppala @ tkk.fi, gsm 050 531 2311 (email and sms preferred)jap @ iki.fi

• Home page:http://wiki.tkk.fi/display/EmbeddedSystemshttp://www.cs.hut.fi/Studies/T-106.5300/2007/

• Discussion forum: opinnot.tik.sulautetut

http://wiki.tkk.fi/display/EmbeddedSystems

http://www.cs.hut.fi/Studies/T-106.5300/2007/



Two lecturers, two tracks

• Theory and Applications (Seppälä)– Background– Theory– Examples

• Hardware and programming (Ala-Paavola)– Programming– Project details



Grading• The grade of the course is calculated with the following

formula: grade = min(5, ((exam + (pre-project + project)*scaling)) + race bonus)

where the grades of the individual parts of the course are: • exam 0-5 • projects 0-5 (pre-project 20 points, car project 100 points,

scaled on a gaussian)

The car race can raise you two grade points for a win, one point for places 2-4.



Excercise Project• Write code to control the

car on an indoor track.• More details in later

lectures• The given hardware for

the car project is used to give an idea of the consideration needed in selecting hardware for a new project

• Examples: slow car, fast car

Examples:Fast Slow

http://www.cs.hut.fi/Studies/T-106.530/2006/mysse/MYSSE - slow car.mov

http://www.cs.hut.fi/Studies/T-106.530/2006/mysse/MYSSE - faster car.mov



The AVR microcontroller

Source: Atmel Datasheet http://www.atmel.com/dyn/resources/prod_documents/2503S.pdf



Course materials and books

• Lecture notes will be available on the course web page

• There are no required books– but there are many good books

• Internet links will be provided– www.embedded.com

http://www.embedded.com/



Main Subjects• Introduction• The car

– project info– technical details

• Computer architecture• Kernels• Peripheral devices• Complex peripherals• Control systems• Measurement and Calibration• Reliability vs. Fault Tolerance• THERAC-25

• System Reliability• Mechanisms for Robustness• Mechanisms for Fault

Tolerance• Hardware oriented

programming• Memory management• The Scheduler• Real Time• Distributed systems• Parallel Programming• Advanced hardware• Exam review



Objectives of this course

• Embedded frame of mind• Experience in programming a successful

embedded system



Development• Background

– What is required– What is available

• Designer’s task– Can it be done?– How?

• Success comes from working around the limitations to get the job done



Common Features of Embedded Design

• Combine hardware and software verytightly (almost inseparably)

• Implemented with limited resources• Real constraints and requirements

– real time– fault tolerance– operating environment

• Embedded systems are often invisible



Interdisciplinary knowledge• Hardware

– bits and bytes vs waves– computers are precise but inaccurate

• Electronics– interfaces– signal levels

• Specific applications• Legal• Business• Engineering knowledge



Specifying Embedded Systems1/2

• Expertise from different fields is needed– software– hardware– mechanics and control– the specific application

• Who leads the group?• Cooperation and overlap is vital



Specifying Embedded Systems2/2

The goal of the specification is to define the:– Functionality of the system– Interfaces of the software and hardware

• modules• fields



System Co-Design

Is a systematic, parallel and combineddesign process of both the hardware and the software where the interfaces aredefined as the design work progresses



Modular DesignSystem specification

System design

Partitioning into modules

Integration and testing

Software specification

Software design

Software implementation

Software testing

Hardware specification

Hardware design

Hardware implementation

Hardware testing



Example: Ship Autopilot Control• Combining a navigation system

to a ship autopilot• Expertise needed in the fields of:

– Naval Engineering– Control Systems– Navigation– Hardware– Software– Maritime rules and legislation



Ship Autopilot Control



User’s Viewpoint

• One of the many tools used to get the shipfrom one place to another



Navigation Expert viewpoint• Application field – defines functional

requirements• Knows the technology and available

interfaces (sensors, controls)• Understands the behavior of the systems

well• Sees the system as a Navigation system

with additional features



Automation Expert Viewpoint

• Extends the knowledge of the Navigationexpert on automation and controltechnology

• Makes available new methods and technologies into the task

• Sees the system mainly as a controlproblem



Control System Algorithms

Source: Modern Control Engineering by Ogata, p. 606



Hardware Expert Viewpoint• Responsible for the equipment which will

operate the Navigation system• Works with the Automation expert to

properly interface and connect to devices• May need to consult other experts• Sees the task as a hardware problem and

the software as a black box



Software Expert Viewpoint• Software is the glue and

the magic of the system• SW expert often controls the

complete design• Designs, implements, and tests the

software with other experts• Sees the hardware as a black box and

seeks to solve the Navigation and Automation issues with software



Ship Autopilot Control



Hardware and Software • Typically, there is a choice of

implementing a feature in HW or SW– many deciding factors:

• the application and the details• cost• safety• legal requirements

• Programmable Hardware• Interfaces



Why care about hardware?

• Embedded systems do not typicallyprovide the luxury of hardware abstractionlayers

• The developer often writes any necessarydrivers

• Using available hardware functions canmake all the difference



DES/3DES En/Decryption• A complex algorithm in a

25MHz AVR microcontroller withFPGA at 4.2 MByte/Secthroughput

http://www.atmel.com/journal/documents/issue4/pg29_30_des3des.pdf

http://www.atmel.com/journal/documents/issue4/pg29_30_des3des.pdf



Apollo Guidance Computer (1969)• Instruction Set: Approximately 20

instructions; 100 noun-verb pairs, data up to triple-precision Word Length: 16 bits (14 bits + sign + parity)

• Memory: ROM (rope core) 36K words; RAM (core) 2K words

• Disk: None• I/O: DSKY (two per spacecraft)• Performance: approx. Add time - 20 s• Basic machine cycle: 2.048 MHz• Technology: RTL bipolar logic (flat pack)• Size: AGC - 24" x 12.5" x 6" (HWD);

DSKY - 8" x 8" x 7" (HWD)• Weight: AGC - 70 lbs; DSKY - 17.5 lbs• Number produced: AGC - 75; DSKY: 138• Cost: Unknown.• Power consumption: Operating: 70W @

28VDC; Standby 15.0 wattsSource: http://www.ddj.com/documents/s=1494/ddj0006hc/

http://www.ddj.com/documents/s=1494/ddj0006hc/



Mars Rovers: Sojourner (1997)• CPU: 80C85 rated at

100Kips (0.1 MIPS)• Memory: 176KB PROM,

576KB RAM, in 16Kbyte pages

• I/O: ~70 sensor channels and services such devices as the cameras, modem, motors and experiment electronics.

• Controlled via landerSource: http://mars.sgi.com/MPF/rover/sojourner.html

http://mars.sgi.com/MPF/rover/sojourner.html



Mars Lander: Pathfinder (1997)• CPU: Radiation Hardened IBM RISC 6000 Single Chip (Rad6000 SC) • Memory: 128 MB DRAM• Clock: 2.5, 5, 10 and 20 MHz. This translates to approximately 2.7, 5.5, 11,

and 22 MIPS• Code: The code was developed using VxWorks as the real-time OS and

"C" and assembly languages. It utilizes object-oriented constructs.• On the system there is only one

computer to control the spacecraft throughout all phases of the mission. The Rover has a very small CPU that it uses once we have landed and the rover is released. All communications to Earth from the spacecraft and rover come through the Rad6000 SC.

Source: http://mars.sgi.com/MPF/mpf/faqs_general.html#mhzImage from: http://mars.jpl.nasa.gov/MPF/mpf/slides/slides-16.html

http://www.wrs.com/

http://mars.sgi.com/MPF/rover/sojourner.html

http://mars.sgi.com/MPF/mpf/faqs_general.html#mhz



Mars Rover: Spirit (2004)• CPU: Radiation Hardened IBM

RISC 6000 Single Chip (Rad6000 SC)

• Memory: 128 MB ECC DRAM, 3MB EEPROM

• Clock: 2.5, 5, 10 and 20 MHz. This translates to approximately 2.7, 5.5, 11, and 22 MIPS

• Code: The code was developed using VxWorks as the real-time OS and "C" and assembly languages. It utilizes object-oriented constructs.

Source: http://www.gcn.com/22_24/news/23246-1.htmlhttp://europe.windriver.com/literature/successstories/WindRiver_customer_story_mars_rover_engl.pdfhttp://www.computerworld.com/governmenttopics/government/story/0,10801,88734,00.html

http://www.wrs.com/

http://www.gcn.com/22_24/news/23246-1.html

http://europe.windriver.com/literature/successstories/WindRiver_customer_story_mars_rover_engl.pdf

http://europe.windriver.com/literature/successstories/WindRiver_customer_story_mars_rover_engl.pdf

http://www.computerworld.com/governmenttopics/government/story/0,10801,88734,00.html

http://www.computerworld.com/governmenttopics/government/story/0,10801,88734,00.html



Engineering Ethics

For a business, cost and necessary profitare important. But an engineer shares the responsibility of designing safe and reliablesystems, regardless of possible pressuresand influence to do it faster, cheaper, now! Every organization is made up of individuals, each responsible for their ownactions.



Therac-25

Source: http://www.uoguelph.ca/~tgallagh/

http://www.uoguelph.ca/~tgallagh/



Suggested Reading• http://sunnyday.mit.edu/therac-25.html

Definitive story of the Therac-25 case

• http://www.ddj.com/documents/s=1494/ddj0006hc/One Giant Leap The Apollo Guidance ComputerSource: Dr. Dobbs Journal (http//www.ddj.com)

• http://www.ddj.com/documents/s=1493/ddj0001hc/Dr. Strangelove Meets IBM: The SAGE SystemOne of the first air-defense computer systems

• http://www.embedded.com/2000/0011/0011br.htmCrash And Burn embedded system disastersSource: Embedded Systems Programming ( http://www.embedded.com/ )

• http://www.fastcompany.com/online/06/writestuff.htmlThey Write the Right Stuff – the story of the space shuttle control softwareSource: Fastcompany

Links tested current on 1.2.2006 OSe

http://sunnyday.mit.edu/therac-25.html



http://www.embedded.com/2000/0011/0011br.htm

http://www.embedded.com/

http://www.fastcompany.com/online/06/writestuff.html

EmbeddedSystems - Aaltoose/embedded/T-106.5300_EmbeddedSystems_Lecture-1_24.01.2008_OSe.pdfJan 24,...

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