Contents. Introduction. Introduction and Motivation Embedded Systems (ES) Content of Lecture Organisational

Transcription

1 Introduction Dipl.-Inf. Mirko Caspar Version: V.r Contents Introduction and Motivation Embedded Systems (ES) characterisation mechatronics requirements classification Content of Lecture Organisational

2 Word Game: CO-Design CO mplex ncurrent rrect ordinated - komplex - nebenläufig - korrekt - koordiniert 01-3 Why HW/SW Codesign? improvements in technology allow new applications design of complex systems requires computer aided tools improvements in formal and automatic design techniques automation in system layer is possible reduce time-to-market and development costs find optimal implementations

3 What is HW/SW Codesign? integrated development of embedded system consisting of hardware-components a (HW) and software-components (SW) HW SW classic design process HW SW HW SW codesign process design process optimisation special requirements to designer analyse the restrictions of HW and SW evaluation of alternative development solutions integration of HW and SW components 01-5 Restrictions of HW/SW general purpose systems example: PC, Workstation trade-off: processor compiler/ operating system embedded systems example: mobile phone, motor control unit trade-off for special processors: processor compiler - trade-off for system development: dedicated HW processors

4 And what is MY advantage? understanding of modern system development insight into a present field of research alternatives in HW/SW implementations algorithms for many application areas jobs 01-7 Contents Introduction and Motivation Embedded Systems (ES) characterisation mechatronics requirements classification Content of Lecture Organisational CO mplex ncurrent rrect ordinated DESIGN

5 Characterisation of ES Hansson 1 : Embedded systems are computers not looking like computers - example: mobile phone, electronic control of washing machine, telephone switchboard Broy 2 : An embedded systems is a - SW/HW unit connected via - sensors and actors with a whole system and - scans, controls and adjusts therein more often used properties: - reactive, hybrid and distributed systems - real-time requirements human user often interacts unconscious with these systems, they are invisible for him 1 Hans Hansson, Mälardalen University 2 Manfred Broy, TU München 01-9 Structure of Embedded Systems Analogue Interfaces Actuators Sensors Digital Interfaces (wired / wireless) Digital Hardware control unit timers peripherals Processor(s) data m. program m. persistent memory Memory(s) ES (HW/ /SW CoDesign p. o. view) ES Analogue Hardware Power Regulation

6 Mechatronics Control Loop controller actuator w(t) e(t) (Regelglied) y R (t) (Steller) y(t) z(t) control process (Regelstrecke) x(t) x R (t) transducer (Messwertgeber) command variable w (Führungsgröße) actuating variable e (Regeldifferenz) measured control variable x R (Erfasste Regelgröße) controller output variable y R (Reglerausgangsgröße) regulating variable y (Stellgröße) disturbance variable z (Störgröße) control variable x (Regelgröße)

7 Realisation as ES Digital IF Actuators Sensors Digital Hardware Processor(s) Memory(s) Analogue IF Analogue Hardware Implementation of ES Domain of ES Behaviour (developer point of view) Actuators / Sensors converter between voltage / purchase current and other physical values (kinetics, optics, ) Typical Implementation (developer point of view) purchase Analogue HW / IF physics differential equations simulation by framework (SPICE, ) Digital Hardware finite state machine Boolean equations HW description language + synthesis framework Processor / Memory sequential execution of machine code assembly language high-level language + compiler Digital Interfaces (partial) embedded system standardised purchase integrated in other parts basic knowledge / THIS LECTURE synthesise

8 Requirements for ES functional requirements data acquisition digital control calculation of control values for actuator (graphical) user interface (GUI) displaying of current system variables and states logging temporal requirements reliability requirements Functional Requirements (I) data acquisition - examination of a actuator which has to be controlled = object (e.g. an industrial robot) - describe these object by state variables - hierarchical, specific structure: RT-Entity - every RT-Entity belongs to control area of a subsystem and is read only

9 Functional Requirements (II) data acquisition means - scan RT-Entities - scanned values are only correct in a short temporal correctness range - set of all correct RT-Entity values is called RT-Database change by discrete time steps (time triggered, TT) change by change in value (event triggered, ET) Temporal Requirements important values: - delay (d object ) time between een setup of new actuating ating variables and beginning reaction of controlled object - response time - time needed by controlled object to get to target value - sampling period - frequency of actual value scan (d sample ) - processor delay - necessary: d computer < d sample (d computer ) - dead time = d object + d computer Sensor ES Actuator

10 Reliability Requirements reliability probability that ES is able to achieve the specified service to point in time t safety reliability in respect of critical errors maintainability value for repair time after an error availability security protection against unauthorised usage up down Failure Repair Failure MTTR MTTF MTBF real time Classification of ES Trade-Off Fail-Safe error detection leads to change in safe state Fail-Operational minimal functionality is assured even in case of error Guaranteed-Response service is also in case of maximum load or error assured Best-Effort system tries to execute services as good as possible no warranty! Resource-Adequate enough resources to execute service in every case Resource-Inadequate enough resources to execute service in usual cases

11 Contents Introduction and Motivation Embedded Systems (ES) characterisation mechatronics requirements classification Content of Lecture Organisational CO mplex ncurrent rrect ordinated DESIGN Lecture Content system development models and methods target t architectures t for HW/SW systems compiler and code generation partitioning, generally HW/SW partitioning HW/SW Codesign I estimation of design parameters Co-Simulation Co-Specifiation (SystemC) interfaces interface synthesis HW/SW Codesign II (next semester)

12 Literature Teich, Jürgen: Digitale Hardware/Software-Systeme. Berlin: Springer, 1997 Hardt, Wolfram: HW/SW-Codesign auf Basis von C-Programmen unter Performanz- Gesichtspunkten. Aachen: Shaker Verlag, 1996 Patterson, David A.; Hennessy, John L.: Computer Organization and Design: The Hardware/Software Interface. 2. Auflage. Oxford: Elsevier Books, 1997 Hennessy, John L.; Golderberg, David; Patterson, David A.: Computer Architecture: A Quantitive Approach. 2. Auflage. San Francisco: Morgan Kaufmann Publishers Inc, 1996 Ward, Stephen A., Halstead, Robert H.: Computation Structures. Cambridge: The MIT Press, Organisational Lecture: Thursday 09:30 11:00 1/B006, weekly (English) Exercises: Friday 09:15 10:45 1/208, weekly (English or German) Friday 11:30 13:00 1/208, weekly Dipl.-Inf. Mirko Caspar Exercises will start 2010/10/22 Exam: written test (English or German), 90 minutes Contact: Mirko Caspar, Room 1/014c, 0371/ [email protected] Content: - download slides before lecture (They'll be incomplete, so you have to complete them!) - download exercise sheets