1. Embedded Systems Introduction to Embedded Software C.-Z. Yang http://syslab.cse.yzu.edu.tw/~czyang Sept.-Dec. 2001

2. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software2 Before we start the course about Embedded Software ……... One very unfortunate aspect of embedded systems –The terminology surrounding term is not very consistent. Another unfortunate problem –The term embedded systems covers such a broad range of products. –Z8 to PowerPC One thing you must keep in mind –Embedded software is a field in which no wisdom is universal.

3. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software3 An example project Moving map –A handheld device that displays for the user a map of the terrain around the user’s current position. –The map display changes as the user and the map device change position. Since you are a designer in the project, what will you do?

4. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software4 An example HP’s Websign (From Pradhan et al., 2001) –http://www.cooltown.hp.com

5. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software5 Xerox PARCTab From Want and Schilit (IEEE Computer, page 32, August 2001) Using a true palm-sized tablet computer with a pen interface linked to a diffuse microcellular infrared network.

6. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software6

7. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software7 What are the basic requirements? Functionality –The system should show major roads and other landmarks available in standard topographic databases. –Location-awareness. User interface –The screen should have at least 400x600 pixel resolution. –The device should be controlled by no more than three buttons. –A menu system should pop up on the screen when buttons are pressed to allow the user to make selections to control the system.

8. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software8 More basic requirements Performance –The map should scroll smoothly. –Upon power-up, a display should take no more than one second to appear. –The system should be able to verify its position an display the current map within 15 seconds. Cost –The selling cost (street price) should be no more than $500.

9. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software9 More basic requirements Physical size and weight –The device should fit comfortably in the palm of the hand. Power consumption –The device should run for at least eight hours on four AA batteries.

10. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software10 A draft of the design proposal A more detailed chart

11. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software11 Finding technical details Location sensing technologies

12. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software12 Architecture design Block diagram GPS receiver Database Renderer Search Engine User Interface Display

13. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software13 Refine the block diagram Now we can have two separate diagrams –Hardware –Software

14. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software14 What have we learned here? No universal wisdom exists in embedded system design Design goals (motivations) Related product survey Requirement specification Detailed technical information Architecture design Hardware/Software refinements

15. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software15 A Brief Overview of System Design Techniques

16. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software16 In the realistic world Now what you have done is just a very small case. More real embedded system designs are inherently complex.

17. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software17 Design methodologies Why? –Design process is important because without it, we cannot reliably deliver the products we want to create. Necessary? –Thinking about the sequence of steps necessary to build something may seem superfluous. –If your are doing your work in your basement, having your own work habits is fine. –However, when several people work together on a project, they need to agree on who will do things and how they will get done.

18. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software18 Product metrics Typical specifications –FunctionalityPDA –Manufacturing costRetail price < NT $7000 –PerformanceMust power up within 3 sec –Power consumption12 hr for 2 AA batteries Three important goals in design process –Time-to-market –Design cost –Quality

19. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software19 Time-to-market Why this goal is so important? –Win the market –Set customer preferences for future generation –Short profitable market life 3-6 months –Calendar deadline

20. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software20 Design cost The costs of designing the system are distinct from manufacturing cost –The cost of engineers’ salaries, –Computers used in design –Equipment costs

21. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software21 Quality Customers not only want their products fast and cheap, they also want them to be right. Is this relevant to the design process? –We must address correctness, reliability, and usability from the beginning of the design job. –So a high-quality product can be available at the end. A good methodology is critical to building systems that work properly.

22. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software22 A Real Application Example

23. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software23 Loss of the Mars Climate Observer In September 1999, the Mars Climate Observer, an unmanned US spacecraft designed to study Mars, was lost. It most likely exploded as it heated up after approaching the planet too closely.

24. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software24 One of the causes Requirements –Design of a flight controller –Lockheed Martin: values in units of pound force –JPL: expecting in newtons

25. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software25 Design Process Flows

26. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software26 Design flows The waterfall model Not a realistic design process

27. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software27 Alternative model The spiral model

28. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software28 Successive refinement In this approach, the system is built several times.

29. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software29 Software/hardware codesign A simple software/hardware design process

30. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software30 Hierarchical design flows In fact, many complex embedded systems are themselves built of smaller designs.

31. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software31 Concurrent engineering When designing a large system along with many people, it is easy to lose track of the complete design flow. Concurrent engineering attempts to take a broader approach and optimize the total flow.

32. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software32 Concurrent engineering efforts Cross-functional teams Concurrent product realization Incremental information sharing Integrated project management Early and continual supplier involvement Early and continual customer focus

33. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software33 An example of concurrent engineering: Telephone systems

34. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software34 Design of PBXs in AT&T Goals: –reduce design time –make other improvements to the end product 7 Steps

35. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software35 7 Steps - 1 Step 1:Benchmarking –Shooting for a 40% reduction in design time AT&T Competitor Time for introducing a new product

36. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software36 7 Steps - 2 Breakthrough improvement –Identify the factors that would influence their effort. –Three major factors increased partnership between design and manufacturing continued existence of the basic organization of design labs and manufacturing support of manages at least two levels above the working level Steering committeeProject officeCore team

37. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software37 7 Steps - 3 Characterization of the current process –The core team built flowcharts and used other techniques to understand the current product development process. Several problems –Too many tasks were performed sequentially –Groups tended to focus on intermediate milestones related to their narrow job descriptions –Too much time was spent waiting in queues –Too many groups had their own databases

38. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software38 7 Steps - 4 Create the target process

39. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software39 7 Steps - 4 New target process

40. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software40 7 Steps - 5 Verify the new process –A pilot product development project to test the new process –Some challenge were identified.

41. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software41 7 Steps - 6 and 7 Implement across the product lines –After the pilot project, the new methodology was rolled out across the product lines. Measure results and improve –The team found that product development time had been reduced from 18-30 months to 11 months.

42. 元智大學資訊工程系 czyang@acm.orgEmbedded Systems - Introduction to Embedded Software42 What is Embedded Software?