《嵌入式实操时作系统》由会员分享，可在线阅读，更多相关《嵌入式实操时作系统（81页珍藏版）》请在金锄头文库上搜索。
1、1嵌入式操作系统第三讲第三讲 嵌入式实时操作系统嵌入式实时操作系统Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.2一、嵌入式实时操作系统C/OS二、嵌入式Linux三、WinCE第三讲、
2、嵌入式实时操作系统分析Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.3本节提要1 13 32 2嵌入式实时操作系统C/OS嵌入式LinuxWinCEEvaluation only.Eva
3、luation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.4一、嵌入式实时操作系统C/OSlC/OS简介l内核结构任务以及调度机制lC/OS的移植Evaluation only.Evaluation only. Created with
4、 Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.5C/OS简介1、C/OSmicro C O S，微控制器操作系统2、C/OS简介l美国人Jean Labrosse 1992年完成l应用面覆盖了诸多领域，如照相机、医疗器械、 音响设备、发动机控制、高速公路电话系统、自动 提款机
5、等 l1998年C/OS IIl网站 www.ucos-Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.6u公开源代码u可移植性（Portable）绝大部分 C/OS-II的源码是用移植性
6、很强的 ANSI C写的。和微处理器硬件相关的那部分是用汇编 语言写的。 C/OS-II可以在绝大多数8位、16位、32 位以至64位微处理器、微控制器 、数字信号处理器（ DSP）上运行。u可裁剪（Scalable）可以只使用 C/OS-II中应用程序需要的那些 系统服务，这样可以减少产品中的 C/OS-II所需的存 储器空间（RAM和ROM）。这种可剪裁性是靠条件 编译实现的。C/OS的性能特点Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Cre
7、ated with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.7u占先式（Preemptive）u多任务C/OS-II可以管理64个任务，然而，目前这一 版本保留8个给系统。应用程序最多可以有56个任务。u可确定性 全部 C/OS-II的函数调用与服务的执行时间 具有可确定性。u任务栈每个任务有自己单独的栈， C/OS-II允许每 个任务有不同的栈空间，以便压低应用程序对RAM的 需求。C/OS的
8、性能特点Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.8u系统服务C/OS-II提供很多系统服务，例如邮箱、消 息队列、信号量、块大小固定的内存的申请与释放、 时间相关函数等。u中断管理
9、中断可以使正在执行的任务暂时挂起，如果优 先级更高的任务被该中断唤醒，则高优先级的任务在 中断嵌套全部退出后立即执行，中断嵌套层数可达255 层。u稳定性与可靠性C/OS的性能特点Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-
10、2011 Aspose Pty Ltd.9l内核结构l任务管理l时间管理l任务之间通信与同步C/OS的内核结构Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.10任务task典型的一个无限
11、循环。void mytask(void *pdata)for (;) do something;waiting;do something;lC/OS II 2.5版本支持64个任务，每个任务一个特定的优先级。优先级越 高，数字越小。（Windows、Linux？）l系统占用了8个任务，保留优先级为0、1、2、3、OS_LOWEST_PRIO-3 、 OS_LOWEST_PRIO-2、 OS_LOWEST_ PRIO-1、 OS_LOWEST_PRIO-0 。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET
12、3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.11建立任务lOS TaskCreate()lOSTaskCreateExtended()Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.
13、0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.12INT8U OSTaskCreate (void (*task)(void *pd), void *p_arg, OS_STK *ptos, INT8U prio) INT8U OSTaskCreateExt (void (*task)(void *pd),void *p_arg,OS_STK *ptos,INT8U pr
14、io,INT16U id,OS_STK *pbos,INT32U stk_size,void *pext,INT16U opt)进程函数体传递给进程的参数进程栈顶指针进程优先级进程ID号进程栈底指针进程栈大小传递给进程控制块 的数据是否初始化进程栈Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2
15、011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.13任务状态Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.14任务控制块（TC
16、B）l任务控制块 OS_TCB是一个数据结构，保存该任务 的相关参数，包括任务堆栈指针，状态，优先级，任务表 位置，任务链表指针等。l所有的任务控制块分为两条链表，空闲链表和使用 链表。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.15任务控制块结构lStruct os_tcb OS_STK *OSTCBStkPtr;struct os_tcb *OSTCBNext;struct os_tcb *OSTCBprev;OS_EVENT
