Eingebettete Systeme 1. Einleitung

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1 Eingebettete Systeme 1. Einleitung Lothar Thiele 1 Organisatorisches WWW: Vorlesung: Lothar Thiele, thiele@tik.ee.ethz.ch Übungskoordination: Ernesto Wandeler, wandeler@tik.ee.ethz.ch Literatur: P. Marwedel: Embedded System Design, Kluwer Acad. Publ, G.C. Buttazzo: Hard Real-Time Computing Systems. Kluwer Academic Publishers, W. Wolf: Computers as Components Principles of Embedded System Design. Morgan Kaufman Publishers, J. Teich: Digitale Hardware/Software Systeme, Springer Verlag, Die Folien enthalten Materialien von J. Rabaey und K. Keuzer (UC Berkeley), Wayne Wolf, Peter Marwedel und aus den oben angegebenen Büchern von J. Teich, G.C. Buttazzo, W. Wolf und P. Marwedel. 2

Wolf: Computers as Components Principles of Embedded System Design. Morgan Kaufman Publishers, 2000. J. Teich: Digitale Hardware/Software Systeme, Springer Verlag, 1997.

2 Vorlesungsinhalt Einleitung Architekturen HW/SW Entwurf Architekturentwurf Modelle Architekturentwurf --Synthese Softwareentwurf Einführung/Modelle Softwareentwurf Echtzeitverhalten/OS 8. Entwurfsmethodik Hardware 3 Software Vorlesungsinhalt Einleitung Architekturen HW/SW Entwurf Hardwareentwurf Modelle Hardwareentwurf --Synthese Softwareentwurf Einführung/Modelle Softwareentwurf Echtzeitverhalten/OS 8. Entwurfsmethodik Hardware 4 Software

Entwurfsmethodik Hardware 3 Software Vorlesungsinhalt 1. 1. Einleitung 2. 2. Architekturen 3. 3. HW/SW Entwurf 4.

3 Embedded Systems Embedded systems (ES) = information processing systems embedded into a larger product Examples: Main reason for buying is not information processing 5 Eingebettete Systeme externer Prozess Mensch- Maschine- Schnittstelle eingebettetes System Sensoren, Aktoren 6

buying is not information processing 5 Eingebettete Systeme externer

4 Beispiele eingebetteter Systeme Auto als integriertes Steuerungs-, Kommunikations- und Informationssystem ABS Getriebe Information Motorsteuerung Lüftungsanlage 7 Beispiel Konsumelektronik, z.b. MP3 Audio, digitale Kamera, Toaster, Thermostat,. Benutzer-Schnittstelle Prozessor Sensoren Aktoren 8

Motorsteuerung Lüftungsanlage 7 Beispiel Konsumelektronik, z.b.

5 Eingebettete Systeme 9 Beispiel Informationssysteme, z.b. drahtlose Kommunikation (Natel, Wireless LAN, ), Speichermedien, Fax/Sprach-Server, 10

6 Characteristics of Embedded Systems (1) Must be dependable: Reliability R(t) = probability of system working correctly provided that is was working at t=0 Maintainability M(d) = probability of system working correctly d time units after error occurred. Availability: probability of system working at time t Safety: no harm to be caused Security: confidential and authentic communication Even perfectly designed systems can fail if the assumptions about the workload and possible errors turn out to be wrong. Making the system dependable must not be an after-thought, it must be considered from the very beginning 11 Characteristics of Embedded Systems (2) Must be efficient: Energy efficient Code-size efficient (especially for systems on a chip) Run-time efficient Weight efficient Cost efficient Dedicated towards a certain application: Knowledge about behavior at design time can be used to minimize resources and to maximize robustness Dedicated user interface (no mouse, keyboard and screen) 12

Availability: probability of system working at time t Safety: no harm to be caused Security: confidential and authentic communication Even perfectly designed systems can fail if the assumptions about

7 Characteristics of Embedded Systems (3) Many ES must meet real-time constraints: A real-time system must react to stimuli from the controlled object (or the operator) within the time interval dictated by the environment. For real-time systems, right answers arriving too late (or even too early) are wrong. A real-time constraint is called hard, if not meeting that constraint could result in a catastrophe [Kopetz, 1997]. All other time-constraints are called soft. A guaranteed system response has to be explained without statistical arguments. 13 Characteristics of Embedded Systems (4) Frequently connected to physical environment through sensors and actuators, Hybrid systems (analog + digital parts). Typically, ES are reactive systems: A reactive system is one which is in continual interaction with is environment and executes at a pace determined by that environment [Bergé, 1995] Behavior depends on input and current state. automata model often appropriate, 14

A real-time constraint is called hard, if not meeting that constraint could result in a catastrophe [Kopetz, 1997]. All other time-constraints are called soft.

8 Vergleich Eingebettete Systeme Wenige Anwendungen, die zur Entwurfszeit bekannt sind. Nicht programmierbar durch den Endbenutzer. Feste Laufzeitbedingungen (zusätzliche Rechenleistung nicht nützlich). Kriterien:» Kosten» Leistungsverbrauch» vorhersagbare Geschwindigkeit» General Purpose Computing Breites Anwendungsspektrum. Programmierbar durch den Endbenutzer. Schneller ist immer besser. Kriterien:» Kosten» Geschwindigkeit» Geschwindigkeit» Geschwindigkeit. 15 Typische Architektur To Outside World Peripheral Bus Microprocessor 4, 8, 16, 32, 4 bit bus CISC, RISC, DSP Integrated peripherals Debug/Test Port Caches Pipeline Multiprocessing Systems DEBUG Port Software Application Code Driver Code / BIOS Real Time Operating System User Interface Communications Protocol Stacks C, C++, Assembly Language, ADA Legacy Code Non-volatile memory EPROM, FLASH, DISK Hybrid Volatile Memory DRAM, SRAM Hybrid System Clocks RTC circuitry System clocks Integrated in uc Imported/Exported 16 Custom Devices ASIC FPGA PAL Standard Devices I/O Ports Peripheral Controllers Communication Devices Ethernet RS-232 SCSI Centronics Proprietary Microprocessor Bus Custom PCI VME PC-102

Kriterien:» Kosten» Geschwindigkeit» Geschwindigkeit» Geschwindigkeit.

9 Wohin geht die Reise? Das Ende der Ära des PC s naht. Ubiquitous computing: Information anytime, anywhere. Eingebettete Systeme stellen hierzu die Basistechnologie bereit. Verborgene Sensoren, Aktoren und Intelligenz in unserer Umgebung Computer zum Anziehen Smart Labels an allen Konsumgütern Intelligente Gebäude, Krankenhaus Elektronisches Papier Computer im Körper Wearable Computer 18

Eingebettete Systeme stellen hierzu die Basistechnologie bereit.

10 Projektbeispiele The Obvious Choice -The Smart Home and Network Appliances Dense network of sensor and monitor nodes Security Environment monitoring and control Object tagging Identification 19 Projektbeispiele Interaktives Museum Wireless node Offices Entrance Exhibits Cafe 20

Environment monitoring and control Object tagging Identification 19

11 Trends Höherer Integrationsgrad Mikroprocessor, Mikrokontroller Speicher + Prozessor + I/O-Einheiten System-on-Chip (SOC) Höherer Anteil an Software Hardware/software Co-design Niedriger Verlustleistungsverbrauch (low power) Vernetzte eingebettete Systeme Etablierter Entwurfsprozess 21

Anteil an Software Hardware/software Co-design Niedriger

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