基于嵌入式实时操作系统的驱动框架

嵌入式设备随着应用领域的扩展呈现出多样性以及复杂性，而嵌入式实时系统普遍不具有良好的设备驱动体系结构，造成驱动开发困难、可移植性差。该文给出了一种嵌入式实时操作系统下的驱动框架，支持各种设备及总线接口，设计了一种快速的设备中断机制，符合嵌入式实时系统的强实时、高可靠的特点，能够满足开发各种嵌入式系统。     

一种支持I/O的核外中断执行算法

通过对嵌入式实时操作系统ARTs-OS的研究,借鉴各种实时系统的中断实现技术,提出了一种支持I/O的核外中断执行算法。     

Windows CE.NET中断架构分析和高速AD驱动程序的开发

分析了Windows CE.NET嵌入式实时系统的中断架构和流式驱动架构,及其设备驱动程序的开发方法.实现了该系统下的高速AD驱动程序的开发,并进行了实际测试.     

嵌入式实时操作系统wJLinux的设计与实现

为了研发具有自主知识产权的基于Linux的嵌入式实时操作系统,需要分析实时系统的任务管理,中断处理和存储管理.在改造Linux内核基础上,对任务管理,中断处理和存储管理进行精心设计,实现一个全新的实时核心.由此,使用此新实时内核开发出了一个具有优良实时性能以及自主知识产权的嵌入式实时操作系统--wJLinux.     

基于嵌入式Linux的USB设备驱动的研究

详细分析了嵌入式USB系统结构,探讨了嵌入式USB设备驱动程序设计中的两个环节USB Host总线驱动和USB Device总线驱动的设计思路和开发过程.     

基于嵌入式uCLinux设备驱动的分析与开发

设备驱动程序的开发已成为嵌入式系统开发的关键.文章分析了嵌入式uCLinux设备驱动程序设计的开发特性,详细探讨了uCLinux设备驱动程序的通用模块框架和具体开发流程,给出了开发基于uCLinux设备驱动程序的核心思想,通过总结归纳为设计开发设备驱动提供有意的参考.     

嵌入式Linux设备驱动程序开发

阐述在嵌入式Linux环境下设备驱动程序的开发,详细探讨了嵌入式Linux设备驱动程序的通用模块框架和具体开发流程,说明了驱动程序与内核的关系,归纳嵌入式Linux设备驱动程序的共性.解析Linux设备驱动程序模块的概念,进一步分析了驱动模块的初始化和卸载这两个关键函数.通过实例论述如何设计和编写模块化的嵌入式Linux设备驱动程序,以及解释驱动程序的关键代码.最后归纳了开发嵌入式Linux设备驱动程序的核心思想.     

嵌入式实时系统的快速开发框架研究

嵌入式实时开发是当今计算机应用研究的热点,该文结合模型驱动架构的系统无关模型和系统相关模型思想,提出了一种基于平台设计的快速开发嵌入式实时系统的方法:首先采用实时应用接口RTAI将嵌入式Linux改造成具有硬实时性能的实时操作系统平台;然后利用Matlab/Simulink/RTW和RTAI-Lab工具对实际系统进行快速化建模、仿真和驱动开发,并自动生成实时的可执行代码;最后将代码加载到嵌入式实时系统.通过倒立摆嵌入式实时控制器系统设计实例说明了这种方法可以有效降低系统设计复杂度,提高嵌入式软件的开发效率.     

μC/OS-Ⅱ的优化移植和设备驱动框架设计

为了减少嵌入式实时操作系统μC/OS-Ⅱ移植在内存匮乏的微控制器上的内存需求并实现其对整个系统设备的管理,提出了μC/OS-Ⅱ的优化移植和设备驱动框架设计;优化移植方式对任务栈和中断栈进行分离减少了系统的内存需求,为所有的中断服务提供唯一的入口使μC/OS-Ⅱ具有中断管理功能;设备驱动框架为设备管理提供统一的规范和API函数从而方便驱动开发和设备操作,通过中断下半部推后执行的机制提高了系统的实时性;测试表明,优化移植后能节省约50%的内存,设备驱动框架能够对设备有效且可靠管理。     

嵌入式实时操作系统及其应用

嵌入式实时操作系统兼有嵌入式和实时性的特点.分析嵌入式实时操作系统的特点及其与通用操作系统的区别;以VxWorks为例,介绍目前市场上常见的嵌入式实时系统及其应用,展望嵌入式实时操作系统的前景.     

基于任务间通信的嵌入式组件模型

通用组件技术如COM、CORBA等技术已较完善,但是它们应用于嵌入式系统却有很多局限,如需要庞大的底层基础支持、没有实时调度能力等。根据嵌入式系统以及应用的特点,分析了现有的通用组件模型和当前嵌入式组件技术的发展现状,提出了一种新的嵌入式组件模型——基于任务间通信的嵌入式组件模型。该模型具有资源消耗小、有实时调度能力、无须大量底层支持的优点,该文介绍了系统框架和实现方法以及组件开发方法。     

在构件化嵌入式操作系统中应用抢占阈值调度

现有基于构件的嵌入式实时软件开发过程着重于从结构的角度分解系统成若干构件,以及重用构件。实践证明,该开发过程还应从运行角度将构件映射成任务,并选择适当的实时调度算法。为此,根据目前的工程实践提出一种实时构件模型,包含将构件映射成任务的方式。描述了当前构件化嵌入式操作系统可以使用的4种调度算法,并比较这些算法的性能特点。提出抢占阈值(preemptionthreshold)调度模型更适合构件化嵌入式实时系统,仿真实验的结果证明了该结论。比较结果和结论对构件化嵌入式实时系统的设计和开发有一定的参考价值。     

A self-adaptive heterogeneous multi-core architecture for embedded real-time video object tracking

Sequential Monte Carlo (SMC) represents a principal statistical method for tracking objects in video sequences by on-line estimation of the state of a non-linear dynamic system. The performance of individual stages of the SMC algorithm is usually data-dependent, making the prediction of the performance of a real-time capable system difficult and often leading to grossly overestimated and inefficient system designs. Also, the considerable computational complexity is a major obstacle when implementing SMC methods on purely CPU-based resource constrained embedded systems. In contrast, heterogeneous multi-cores present a more suitable implementation platform. We use hybrid CPU/FPGA systems, as they can efficiently execute both the control-centric sequential as well as the data-parallel parts of an SMC application. However, even with hybrid CPU/FPGA platforms, determining the optimal HW/SW partitioning is challenging in general, and even impossible with a design time approach. Thus, we need self-adaptive architectures and system software layers that are able to react autonomously to varying workloads and changing input data while preserving real-time constraints and area efficiency. In this article, we present a video tracking application modeled on top of a framework for implementing SMC methods on CPU/FPGA-based systems such as modern platform FPGAs. Based on a multithreaded programming model, our framework allows for an easy design space exploration with respect to the HW/SW partitioning. Additionally, the application can adaptively switch between several partitionings during run-time to react to changing input data and performance requirements. Our system utilizes two variants of a add/remove self-adaptation technique for task partitioning inside this framework that achieve soft real-time behavior while trying to minimize the number of active cores. To evaluate its performance and area requirements, we demonstrate the application and the framework on a real-life video tracking case study and show that partial reconfiguration can be effectively and transparently used for realizing adaptive real-time HW/SW systems.     

Comparison of component frameworks for real-time embedded systems

The use of components significantly helps in development of real-time embedded systems. There have been a number of component frameworks developed for this purpose, and some of them have already became well established in this area. Even though these frameworks share the general idea of component-based development, they significantly differ in the range of supported features and maturity. This makes it relatively difficult to select the right component framework and thus poses a significant obstacle in adoption of the component-based development approach for developing real-time embedded systems. To provide guidance in choosing a component framework, or at least relevant concepts when building a custom framework, we present a survey, which illustrates distinguishing features and provides comparison of selected modern component-based frameworks for real-time embedded systems. Compared to other existing surveys, this survey focuses specifically on criteria connected with real-time and embedded systems. Further, to be practically relevant, we restrict the survey only to the frameworks that support the full development life cycle (i.e. from design till execution support). In this context, the survey illustrates the complexity of development in each framework by giving specification and code samples.     

User-level Real-Time Network System on Microkernel-based Operating Systems

This paper presents the design and implementation of a user-level real-time network system in Real-Time Mach. Traditional network systems for microkernel based operating systems, which tend to focus on high performance and flexibility, are not suitable for real-time communication. Our network system provides a framework for implementing real-time network protocols which require to bound protocol processing time, and it is suitable for implementing on microkernel based operating systems. In this paper, we especially focus on the aspects to avoid the priority inversion problem in order to make network systems more preemptable and predictable. We also describe the feasibility of our network system for building distributed multimedia systems.     

基于S3C2416的嵌入式USB2.0/以太网转换器设计

文章介绍了一个基于S3C2416的嵌入式USB2.0/以太网转换器设计方案,采用以太网控制器DM9000a成功实现USB2.0到以太网的高速、高效率的数据交换。论文阐述了USB接口和网络接口电路基础上,重点对嵌入式Linux系统下的USB Gadget驱动框架和DM9000a的驱动程序进行了具体分析。     

层次化动态实时调度框架的设计与实现．

现有嵌入式系统具有应用场景多变、实时性要求严格、上层应用复杂、鲁棒性较强等特点,在嵌入式操作系统层面对系统防危性要求较高。时间隔离机制是提高系统防危性的重要组成部分,为此,提出一种将层次化动态实时调度框架作为时间隔离的实现策略。引入任务同质性的概念进行任务分划,将产生的任务集作为层次框架的基础,证明多层次框架下实时任务的可调度性条件,设计调度算法结构并实现调度算法的动态切换。仿真结果和理论分析表明,该调度框架在保证上下文切换时间复杂度稳宦的前撂下．可楫高秦统防毹性并动态应对系统债载的变化。     

A tool for analyzing and fine tuning the real-time properties of an embedded system

This paper describes a computer-aided software engineering (CASE) tool that helps designers analyze and fine-tune the timing properties of their embedded real-time software. Existing CASE tools focus on the software specification and design of embedded systems. However, they provide little, if any, support after the software has been implemented. Even if the developer used a CASE tool to design the system, their system most likely does not meet the specifications on the first try. This paper includes guidelines for implementing analyzable code, profiling a real-time system, filtering and extracting measured data, analyzing the data, and interactively predicting the effect of changes to the real-time system. The tool is a necessary first step towards automating the debugging and fine tuning of an embedded system's temporal properties.