Microc/OS-II

摘要

From the Book: This book describes the design and implementation of µC/OS-II (pronounced Micro C O S 2), which stands for MicroController Operating System Version 2. µC/OS-II is based on µC/OS, The Real-Time Kernel that was first published in 1992. Thousands of people around the world are using µC/OS in all kinds of applications, such as cameras, medical instruments, musical instruments, engine controls, network adapters, highway telephone call boxes, ATM machines, industrial robots, and more. Numerous colleges and universities also have used µC/OS to teach students about real-time systems.   µC/OS-II is upward compatible with µC/OS V1.11 but provides many improvements, such as the addition of a fixed-sized memory manager; user-definable callouts on task creation, task deletion, task switch, and system tick; TCB extensions support; stack checking; and much more. I also added comments to just about every function, and I made µC/OS-II much easier to port to different processors. The source code in µC/OS was placed in two files. Because µC/OS-II contains many new features and functions, I decided to split µC/OS-II into a few source files to make the code easier to maintain.   If you currently have an application that runs with µC/OS, it should run virtually unchanged with µC/OS-II . All of the services (i.e., function calls) provided by µC/OS have been preserved. You may, however, have to change include files and product build files to point to the new filenames.   This book contains all the source code for µC/OS-II and a port for the Intel 80x86processor running in real mode and for the large model. The code was developed on a PC running the Microsoft Windows 95 operating system. Examples run in a DOS-compatible box under the Windows 95 environment. Development was done using the Borland International C/C++ compiler V3.1. Although µC/OS-II was developed and tested on a PC, µC/OS-II was actually targeted for embedded systems and can be ported easily to many different processor architectures. µC/OS-II Features Source Code   As I mentioned previously, this book contains all the source code for µC/OS-II . I went to a lot of effort to provide you with a high-quality product. You may not agree with some of the style constructs that I use, but you should agree that the code is both clean and very consistent. Many commercial real-time kernels are provided in source form. I challenge you to find any such code that is as neat, consistent, well commented, and well organized as that in µC/OS-II . Also, I believe that simply giving you the source code is not enough. You need to know how the code works and how the different pieces fit together. You will find that type of information in this book. The organization of a real-time kernel is not always apparent when staring at many source files and thousands of lines of code. Portable   Most of µC/OS-II is written in highly portable ANSI C, with target microprocessor-specific code written in assembly language. Assembly language is kept to a minimum to make µC/OS-II easy to port to other processors. Like µC/OS, µC/OS-II can be ported to a large number of microprocessors as long as the microprocessor provides a stack pointer and the CPU registers can be pushed onto and popped from the stack. Also, the C compiler should provide either in-line assembly or language extensions that allow you to enable and disable interrupts from C. µC/OS-II can run on most 8-, 16-, 32-, or even 64-bit microprocessors or microcontrollers and DSPs.   All the ports that currently exist for µC/OS can be converted to µC/OS-II in about an hour. Also, because µC/OS-II is upward compatible with µC/OS, your µC/OS applications should run on µC/OS-II with few or no changes. Check for the availability of ports on the µC/OS-II Web site at www.uCOS-II.com. ROMable   µC/OS-II was designed for embedded applications. This means that if you have the proper tool chain (i.e., C compiler, assembler, and linker/locator), you can em