2. Introduction to Embedded Systems Introduction to Embedded Systems

3. Introduction to Embedded Systems Introduction zWhat are embedded systems? zWhat makes them different? zReal time operation zMany sets of constraints on designs zChallenges in embedded computing system design. zDesign methodologies.

4. Introduction to Embedded Systems Definition zEmbedded system: any device that includes a programmable computer but is not itself a general- purpose computer. zComputer purchased as part of some other piece of equipment Typically dedicated software (may be user- customizable) Often replaces previously electromechanical components Often no “real” keyboard Often limited display or no general- purpose display device: don’t need all the general-purpose bells and whistles.

5. Introduction to Embedded Systems What is an embedded system

6. Introduction to Embedded Systems Examples Office systems and mobile equipment Building systems Manufacturing and Process Control Answering machines Copiers Faxes Laptops and notebooks Mobile Telephones PDAs, Personal organisers Still and video cameras Telephone systems Time recording systems Printer Microwave Air conditioning Backup lighting and generators Building management systems CTV systems Fire Control systems Heating and ventilating systems Lifts, elevators, escalators Lighting systems Security systems Security cameras Sprinkler systems Automated factories Bottling plants Energy control systems Manufacturing plants Nuclear power stations Oil refineries and related storage facilities Power grid systems Power stations Robots Switching systems Water and sewage systems

7. Introduction to Embedded Systems Examples TransportCommunicationsOther equipment Aeroplanes Trains Buses Marine craft Jetties Automobiles Air Traffic Control Signalling Systems Radar Systems Traffic Lights Ticketing machines Speed cameras, Radar speed detectors Telephone systems Cable systems Telephone switches Satellites Global Positioning System Automated teller systems Credit card systems Medical Imaging equipment Domestic Central Heating control VCRs

8. Introduction to Embedded Systems Automotive embedded systems zToday’s high-end automobile may have 100 microprocessors: y4-bit microcontroller checks seat belt; ymicrocontrollers run dashboard devices; y16/32-bit microprocessor controls engine.

9. Introduction to Embedded Systems BMW 850i brake and stability control system zAnti-lock brake system (ABS): pumps brakes to reduce skidding. zAutomatic stability control (ASC+T): controls engine to improve stability. zABS and ASC+T communicate. yABS was introduced first---needed to interface to existing ABS module.

10. Introduction to Embedded Systems BMW 850i, cont’d. brake sensor brake sensor brake sensor brake sensor ABS hydraulic pump

11. Introduction to Embedded Systems Embedded systems rule the market place 80 Million PCs vs. 3Billion Embedded CPUs Annually Embedded market growing; PC market mostly saturated

12. Introduction to Embedded Systems Why are embedded systems different from desktop computers ?

13. Introduction to Embedded Systems 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

14. Introduction to Embedded Systems Characteristics 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 $. 05 adds up over 1,000, 000 units

15. Introduction to Embedded Systems Embedding a computer CPU mem input output analog embedded computer

16. Introduction to Embedded Systems Why use microprocessors? zMicroprocessors simplify the design of families of products. zMicroprocessors are often very efficient: can use same logic to perform many different functions, but Microprocessors use much more logic to implement a function than does custom logic. zAlternatives: field-programmable gate arrays (FPGAs), ASIC’s, custom logic, etc. zWhat about MicroControllers or DSP’s…. zCustom logic is a clear winner for low power devices.

17. Introduction to Embedded Systems An Embedded Control System Designer’s View

18. Introduction to Embedded Systems A Customer View

19. Introduction to Embedded Systems Design teams zOften designed by a small team of designers. zOften must meet tight deadlines. y6 month market window is common. yCan’t miss back-to-school window for calculator.

20. Introduction to Embedded Systems Challenges in embedded system design zHow much hardware do we need? yHow big is the CPU? Memory? zHow do we meet our deadlines? yFaster hardware or cleverer software? zHow do we minimize power? yTurn off unnecessary logic? Reduce memory accesses?

21. Introduction to Embedded Systems Challenges, etc. zDoes it really work? yIs the specification correct? yDoes the implementation meet the spec? yHow do we test for real-time characteristics? yHow do we test on real data? zHow do we work on the system? yObservability, controllability? yWhat is our development platform?

22. Introduction to Embedded Systems Embedded System Designer Skill Set Appreciation for multi- disciplinary nature of design Both hardware & software skills Understanding of engineering beyond digital logic Ability to take a project from specification through production Communication & teamwork skills Work with other disciplines, manufacturing, marketing Work with customers to understand the real problem being solved Make a good presentation; even better -- write “trade rag” articles And, by the way, technical skills too… Low level: Microcontrollers, FPGA/ ASIC, assembly language, A/ D, D/ A High level: Object- oriented Design, C/ C++, Real Time Operating Systems Meta level: Creative solutions to highly constrained problems Likely in the future: Unified Modeling Language, embedded networks Uncertain future: Java, Windows CE

23. Introduction to Embedded Systems Design methodologies zA procedure for designing a system. zUnderstanding your methodology helps you ensure you didn’t skip anything. zCompilers, software engineering tools, computer-aided design (CAD) tools, etc., can be used to: yhelp automate methodology steps; ykeep track of the methodology itself.

24. Introduction to Embedded Systems Design goals zPerformance. yOverall speed, deadlines. zFunctionality and user interface. zManufacturing cost. zPower consumption. zOther requirements (physical size, etc.)

25. Introduction to Embedded Systems Levels of abstraction requirements specification architecture component design system integration

26. Introduction to Embedded Systems Our requirements form

27. Introduction to Embedded Systems Example: GPS moving map requirements zMoving map obtains position from GPS, paints map from local database. lat: 40 13 lon: 32 19 I-78 Scotch Road

28. Introduction to Embedded Systems GPS moving map needs zFunctionality: For automotive use. Show major roads and landmarks. zUser interface: At least 400 x 600 pixel screen. Three buttons max. Pop-up menu. zPerformance: Map should scroll smoothly. No more than 1 sec power-up. Lock onto GPS within 15 seconds. zCost: $500 street price = approx. $100 cost of goods sold.

29. Introduction to Embedded Systems GPS moving map needs, cont’d. zPhysical size/weight: Should fit in hand. zPower consumption: Should run for 8 hours on four AA batteries.

30. Introduction to Embedded Systems GPS moving map requirements form

31. Introduction to Embedded Systems Specification zA more precise description of the system: yshould not imply a particular architecture; yprovides input to the architecture design process. zMay include functional and non-functional elements. zMay be executable or may be in mathematical form for proofs.

32. Introduction to Embedded Systems GPS specification zShould include: yWhat is received from GPS; ymap data; yuser interface; yoperations required to satisfy user requests; ybackground operations needed to keep the system running.

33. Introduction to Embedded Systems Architecture design zWhat major components go satisfying the specification? zHardware components: yCPUs, peripherals, etc. zSoftware components: ymajor programs and their operations. zMust take into account functional and non-functional specifications.

34. Introduction to Embedded Systems GPS moving map block diagram GPS receiver search engine renderer user interface database display

35. Introduction to Embedded Systems GPS moving map hardware architecture GPS receiver CPU panel I/O display frame buffer memory

36. Introduction to Embedded Systems GPS moving map software architecture position database search renderer timer user interface pixels

37. Introduction to Embedded Systems Designing hardware and software components zMust spend time architecting the system before you start coding. zSome components are ready-made, some can be modified from existing designs, others must be designed from scratch.

38. Introduction to Embedded Systems System integration zPut together the components. yMany bugs appear only at this stage. zHave a plan for integrating components to uncover bugs quickly, test as much functionality as early as possible.

39. Introduction to Embedded Systems 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. References: Overheads for Computers as Components, W.Wolf.Morgan Kaufman. Embedded Systems in the Real World, Phillip Koopman. Carnegie Mellon University.