Master the fundamental concepts of real-time embedded system programming and jumpstart your embedded projects with effective design and implementation practices. This book bridges the gap between higher abstract modeling concepts and the lower-level programming aspects of embedded systems development. You gain a solid understanding of real-time embedded systems with detailed practical examples and industry wisdom on key concepts, design processes, and the available tools and methods.
Delve into the details of real-time programming so you can develop a working knowledge of the common design patterns and program structures of real-time operating systems (RTOS). The objects and services that are a part of most RTOS kernels are described and real-time system design is explored in detail. You learn how to decompose an application into units and how to combine these units with other objects and services to create standard building blocks. A rich set of ready-to-use, embedded design “building blocks” is also supplied to accelerate your development efforts and increase your productivity.
Experienced developers new to embedded systems and engineering or computer science students will both appreciate the careful balance between theory, illustrations, and practical discussions. Hard-won insights and experiences shed new light on application development, common design problems, and solutions in the embedded space. Technical managers active in software design reviews of real-time embedded systems will find this a valuable reference to the design and implementation phases.
Qing Li is a senior architect at Wind River Systems, Inc., and the lead architect of the company’s embedded IPv6 products. Qing holds four patents pending in the embedded kernel and networking protocol design areas. His 12+ years in engineering include expertise as a principal engineer designing and developing protocol stacks and embedded applications for the telecommunications and networks arena. Qing was one of a four-member Silicon Valley startup that designed and developed proprietary algorithms and applications for embedded biometric devices in the security industry.
Caroline Yao has more than 15 years of high tech experience ranging from development, project and product management, product marketing, business development, and strategic alliances. She is co-inventor of a pending patent and recently served as the director of partner solutions for Wind River Systems, Inc.
About the Authors
10.1 Introduction
10.1 Introduction
Exceptions and interrupts are part of a mechanism provided by the majority of embedded processor architectures to allow for the disruption of the processor's normal execution path. This disruption can be triggered either intentionally by application software or by an error, unusual condition, or some unplanned external event.
Many real-time operating systems provide wrapper functions to handle exceptions and interrupts in order to shield the embedded systems programmer from the low-level details. This application-programming layer allows the programmer to focus on high-level exception processing rather than on the necessary, but tedious, prologue and epilogue system-level processing for that exception. This isolation, however, can create misunderstanding and become an obstacle when the programmer is transformed from an embedded applications programmer into an embedded systems programmer.
Understanding the inner workings of the processor exception facility aids the programmer in making better decisions about when to best use this powerful mechanism, as well as in designing software that handles exceptions correctly. The aim of this chapter is to arm the programmer with this knowledge.
This chapter focuses on:
· the definitions of exception and interrupt,
· the applications of exceptions and interrupts,
· a closer look at exceptions and interrupts in terms of hardware support, classifications, priorities, and causes of spurious interrupts, and
· a detailed discussion on how to handle exceptions and interrupts.
