[编程资料大全].learn_RT_programming

Real-Time Copyright © A.J. Kornecki, 2000 page 1 Learning Real-Time Programming Concepts through VxWorks Lab Experiments Andrew J. Kornecki korn@db.erau.edu Embry Riddle Aeronautical University, Daytona Beach, FL http ://faculty.erau.edu/korn Janusz Zalewski jza@ece.engr.ucf.edu University of Central Florida, Orlando, FL Daniel Eyassu Daniel.Eyassu @lmco .com Lockheed-Martin Information Systems, Orlando, FL CSEE@T2000 Paper Presentation Real-Time Copyright © A.J. Kornecki, 2000 page 2 Agenda n Background n Laboratory Infrastructure n Tornado n Experiment Format n Real Time Concepts n Class Projects n Closing Remarks Real-Time Copyright © A.J. Kornecki, 2000 page 3 Background (1) n Modern computer applications: – have predictable and guaranteed timing behavior thus failing if the timing constraints are not met (real- time) – interact with and control the environment (safety critical) – operate continuously as a part of a larger system (embedded) Real-Time Copyright © A.J. Kornecki, 2000 page 4 Background (2) n Therefore: – industry badly needs engineers familiar with concepts and practices applicable to development of time- critical reactive systems – concepts of timing, concurrency, synchronization and communication, resource sharing, and external device handling need to be addressed in computing programs Real-Time Copyright © A.J. Kornecki, 2000 page 5 Real Time System Components n Hardware - processor, bus, peripheral devices, memory, cache n Operating System - scheduling, thread management, memory management, interrupt handling, input/output, application programming interface (API),priority inheritance avoidance n Application Design - methodologies, CASE Tools, notations, process n Application Implementation - synchronization, communication, threads, development support, run-time support Real-Time Copyright © A.J. Kornecki, 2000 page 6 Nature of Real-Time Software: n timely response to events n dynamic tasks to handle for events, entities, and functions (process, thread) n tasks activated periodically or sporadically n completion of each task before the deadline n task interaction through synchronization and communication n system shall not hang/crash Real-Time Copyright © A.J. Kornecki, 2000 page 7 Application Domains n process control (chemical industry, food processing) n robotics (manufacturing, automated control) n avionics (flight management, GPS) n aerospace (jet engine control, fly-by-wire) n military (weapon management, encryption) n data collection (acquisition, signal processing) n communication (fax machines, digital phones) n appliances (microwave, dishwasher, thermostats) n automotive (engine/cruise control, anti-lock brakes) n computer peripherals (printers, terminals, modems) Real-Time Copyright © A.J. Kornecki, 2000 page 8 The Development Environment n native environment: development on the same platform as the resulting executable n host/target environment: development on the host with the executable downloaded to target Real-Time Copyright © A.J. Kornecki, 2000 page 9 Laboratory Infrastructure n Students must have access to a development environment supporting the entire software life-cycle n Students must be able to develop code on the host and download, debug and test on the target n Typical software components of the lab must include CASE tools, development tools, real- time kernels, performance analysis tools n Selected environment have been Tornado, courtesy of a software grant from Wind River System (WRS) Academic Program Real-Time Copyright © A.J. Kornecki, 2000 page 10 WRS Tornado - Components n VxWorks Kernel on target n Network and interfacing facilities: – Target Server on the host and Debug Agent on the target – Boot ROM on target – Module Loader and Symbol Table n Development tools on the host: – WindSh - C and Tk/Tcl interface to target – CrossWind - graphic GNU gdb debugger – Browser - graphic presentation of target code – WindView - graphic logic analyzer – VxSim - target simulator Real-Time Copyright © A.J. Kornecki, 2000 page 11 Fig 1. Tornado Architecture (from Wind River Systems promotional literature) Real-Time Copyright © A.J. Kornecki, 2000 page 12 WRS Tornado - VxWorks n VxWorks - a widely adopted industrial real- time operating system (RTOS) n VxWorks is flexible, with powerful API’s, scaleable, reliable, used in mission-critical applications n VxWorks micro-kernel supports real-time features (fast multitasking, hardware interrupts, both priority-preemptive and round- robin scheduling, efficient inter-task communication mechanisms, etc.) Real-Time Copyright © A.J. Kornecki, 2000 page 13 Host Development Interface Real-Time Copyright © A.J. Kornecki, 2000 page 14 Experiment Format - General n Experiments are designed to be completed by a student independently, while learning the theory component in the classroom n Lab description is accessible from the ERAU Real-Time Lab Web server (http ://rt.db.erau.edu) to provide an easy access to the experiments both from the laboratory and from home n Each lab experiment contains: introduction, objectives, description, example program, procedures, follow on experiment, and additional information Real-Time Copyright © A.J. Kornecki, 2000 page 15 Experiment Format - Topics n Timing n Multitasking and Concurrency n Synchronization and Semaphores n Communication and Message Queues n Scheduling – round robin – priority pre-emptive – priority inversion n Signals and Timers n Interrupts Real-Time Copyright © A.J. Kornecki, 2000 page 16 Class Projects - General n Following the lab work, students are engaged in a small team project requiring the team to produce software life-cycle artifacts n The team uses elements of Personal/Team Software Process n The project deliverables include Internet accessible documentation and in-class presentation with the system demonstration n The projects are implemented on VME VxWorks target with user interface on a remote UNIX/WindowNT workstation (TCP/IP) Real-Time Copyright © A.J. Kornecki, 2000 page 17 Class Projects - Examples n Real-Time Data Acquisition and Control n Real-Time GUI Implementation n TCAS Simulator n Autonomous Lunar Explorer n Web Game n Avionics Data Acquisition n Security System n Coffee Maker n ….. Check ERAU CS450 and MSE545 course pages Real-Time Copyright © A.J. Kornecki, 2000 page 18 Conclusions n Laboratory experiments facilitate learning real-time concepts n Lab settings encourage experimentation and analysis of results n Web interface provides easy access n Projects challenge students giving them opportunity to apply the concepts learned in classroom