Embedded Systems Design Paul Pop, associate professor Embedded systems engineering section

2 Embedded Systems  Invisible computers, inside most of the devices we use, from a music player, a mobile phone, to cars, trains, medical equipment, and so on.  an embedded system special-purpose computer system, part of a larger system which it controls  More than humans on the planet, already  40 billion of such devices by 2020  99% of processors used in embedded systems  4 billion embedded processors sold last year  €71 billion global market in 2009, growth of 14%  Market size is about 100 times the desktop market

3 oo ooo o o o o o o o o o o o o o o o o o o o o o o o o o o o Embedded systems are everywhere Our daily lives depend on embedded systems

4 Product: Sonicare Plus toothbrush. Microprocessor: 8-bit Zilog Z8. From your bathroom...

5 To Mars...  Product: NASA's Mars Sojourner Rover. Microprocessor: 8-bit Intel 80C85.

6 Big...

7 And small...

8 Characteristics of embedded systems  Single-functioned  Dedicated to perform a single function  Complex functionality  Often have to run sophisticated algorithms or multiple algorithms.  Cell phone, laser printer.  Tightly-constrained  Low cost, low power, small, fast, etc.  Reactive and real-time  Continually reacts to changes in the system’s environment  Must compute certain results in real-time without delay  Safety-critical  Must not endanger human life and the environment

9 Level of dependency Automotive Electronics Embedded systems: 90% future innovations 40% price ACC Stop&Go BFD ALC KSG 42 voltage Internet Portal GPRS, UMTS Telematics Online Services BlueTooth Car Office Local Hazard Warning Integrated Safety System Steer/Brake-By-Wire I-Drive Lane Keeping Assist. Personalization Software Update Force Feedback Pedal… Electronic Injections Check Control Speed Control Central Locking … Navigation System CD-Changer ACC Adaptive Cruise Control Airbags DSC Dynamic Stability Control Adaptive Gear Control Xenon Light BMW Assist RDS/TMC Speech Recognition Emergency Call… Electronic Gear Control Electronic Air Condition ASC Anti Slip Control ABS Telephone Seat Heating Control Autom. Mirror Dimming … source: BMW

10 Automotive architecture example

11 Evolution of handsets and technology

12 LCDs Application processor Baseband ASIC Mixed- Signal ASIC Energy management ASIC Position sensors 512 MB DDR DRAM 512MB NAND FLASH 2MPix camera module 64MB NOR FLASH 64MB SDRAM RF Battery White LED driver Frame buffer ASIC MMC ARM9 UMA core Keyboard LED Flash ARM9 UMA core BT Module SIM IHF Back-light LEDs Charger Smartphone architecture example

13 Architectures: Networked embedded systems Distributed across networks... Several functions per processor Distributed functionality

14 Application areas: critical vs. best-effort  Critical (e.g., avionics)  Based on worst-case assumptions  Static reservation of resources  Schedulability analysis and static scheduling  Simple execution platforms  Leads to overdesign (underutilization)  Best effort (e.g., multimedia, networks)  Based on average-case  Dynamic reservation of resources  Sophisticated architectures  Adaptive scheduling mechanisms  Leads to temporary unavailability  Bridging the gap: partitioned architectures

Leading edge chip in ,000 transistors Leading edge chip in ,000,000 transistors Graphical illustration of Moore’s law  Something that doubles frequently grows more quickly than most people realize!  A 2002 chip could hold about 15, chips inside itself

16

17 More Moore vs. More than Moore

18 Tubes to Chips: Integrated Circuits  Driven by Information Processing needs IBM 701 calculator (1952) IBM Power 5 IC (2004) Slide soruce: Krish Chakrabarty, Duke University

19 Tubes to Chips: Biochips  Driven by biomolecular analysis needs Test tube analysis Agilent DNA analysis Lab on a Chip (1997) Slide soruce: Krish Chakrabarty, Duke University

20 Tubes to Chips: Biochips, cont. Test tubes Robotics Microfluidics Automation Integration Miniaturization Automation Integration Miniaturization Automation Integration Miniaturization Slide soruce: Krish Chakrabarty, Duke University

21 Biochip Architecture Slide soruce: Krish Chakrabarty, Duke University

22 Embedded systems design problem  Find an implementation that can perform the computation such that the requirements are satisfied.  Embedded systems perform computations (software) that are subject to physical constraints (hardware)  Reaction to a physical environment: deadline, throughput, jitter  Execution on a physical platform: processor speed, power, reliability  The need for an embedded systems design discipline  Computer science separates computation from physical constraints  Computer engineering ignores computation

23 Traditional embedded systems design  Design and build the target hardware  Develop the software independently  Integrate them and hope it works Does not work for complex systems

24 Embedded software: size and deployment

25 Embedded software: complexity growth

26 Increasing complexity (telecom example)

µ 0.25µ0.18µ 0.15µ 0.12µ 0.1µ Log Scale Gates/cm 2 Moore’s Law Widening Gap Design Productivity Software Productivity Technology (micron) Design crisis

28 We need a better design methodology  Design methodology: the process of creating a system  Goal: optimize competing design metrics  Time-to-market  Design cost  Manufacturing cost  Quality, etc.  Design flow: sequence of steps in a design methodology.  May be partially or fully automated.  Use tools to transform, verify design.  Design flow is one component of design methodology. Methodology also includes management, organization, etc.

29 Abstraction and clustering abstract Transistor Model Capacity Load 1970’s cluster abstract Gate Level Model Capacity Load 1980’s RTL cluster abstract SDF Wire Load 1990’s IP Blocks cluster abstract IP Block Performance Inter IP Communication Performance Models RTL Clusters SW Models Year

30 Abstraction and clustering: Platforms  The “PC platform” makes development easier  x86 instruction-set architecture  fully specified set of buses and  a specified set of I/O devices  Similar platform definitions for specific embedded systems application areas Output DevicesInput devices Hardware Platform IO Hardware Software Network Software Platform Application Software Platform API

31 Model of system implementation System platform model System-level design tasks Evaluation Software synthesis Hardware synthesis Application model Application model Architecture model System-level design Constructive vs. improvement Analysis vs. simulation

32 Typical design tasks: Mapping and scheduling  Given  Application: set of interacting processes  Platform: set of nodes  Timing constraints: deadlines  Determine  Mapping of processes and messages  Schedule tables for processes and messages  Such that the timing constraints are satisfied S2S2 S1S1 P1P1 P4P4 P2P2 m1m1 m2m2 m3m3 m4m4 P3P3 N1N1 N2N2 Bus Schedule table Deadline P1P1 P4P4 P2P2 P3P3 m1m1 m2m2 m3m3 m4m4 N1N1 N2N2

33 Biochips design tasks Scheduling Binding Placement Allocation

34 Design-space exploration

35 Safety-Critical Systems  Safety is a property of a system that will not endanger human life or the environment.  A safety-related system is one by which the safety of the equipment or plant is ensured.  Safety-critical system is:  Safety-related system, or  High-integrity system Our daily lives depend on embedded systems