基于FPGA的PCIe总线DMA控制器的设计与验证

PCIe总线是为了解决高速率高带宽提出的新一代总线,随着处理器技术的发展,在互连领域中,PCIe总线的使用越来越多;为了实现上位机与FPGA之间的高速数据交换,基于FPGA设计了能够高速传输数据的DMA控制器,本设计的验证是基于北京航天测控公司开发的6槽机箱、嵌入式控制器(基于PCIe总线)、以及数字I/O模块;设计实现了嵌入式控制器与数字I/O模块之间的数据传输,并且通过了验证,证明了DMA控制器功能的正确性;加入DMA控制器后,写数据传输速率达到610MB/s,提高到了原来的7倍;读数据传输速率达到492MB/s,提高到原来的11倍,满足系统的设计要求;该控制器在大带宽的数据传输中有广泛的应用。     

基于XC6SLX45T平台的PCIe数据卡设计

为提升数据传输速率、提高数据处理灵活性,提出一种基于FPGA的的PCIe数据卡设计方法.该方案选用Xilinx公司的XC6SLX45T平台,采用IP核的方式设计了一款PCIe数据卡.该卡采用DMA传输模式,通过DMA读写提高传输速率,其数据传输速率可达到400 Mbps.     

基于PCIe的多路传输系统的DMA控制器设计

为了避免PCIe传输过程中PIO写延时、主机与嵌入式处理系统交互次数过多等问题对于传输带宽的影响,设计了一种基于命令缓冲机制的直接存储访问（DMA）控制器以提高传输带宽利用率。采用FPGA端内部设置命令缓冲区的方式,使得DMA控制器可以缓存PC端的数据传输请求,FPGA根据自身需求动态地访问PC端存储空间,增强了传输灵活性;同时,提出一种动态拼接的DMA调度方法,通过合并相邻存储区访问请求的方式,进一步减少主机与硬件的交互次数和中断产生次数。系统传输速率测试实验中,DMA写最高速率可达1631 MB/s,DMA读最高速率可达1582 MB/s,带宽最大值可达PCIe总线理论带宽值的85.4%;与传统PIO方式的DMA传输方法相比,DMA读带宽提升58%,DMA写带宽提升36%。实验结果表明,本设计能够有效提升DMA传输效率,明显优于PIO方式。     

FPGA的双缓冲模式PCI Express总线设计

介绍了软件无线电平台中基于FPGA的双缓冲模式PCI Express（PCIE）总线的设计与实现。设计了基于Xilinx Virtex-6 FPGA的通用软件无线电平台,开发了基于Linux系统的驱动程序和PCIE硬核的DMA控制器。双缓;中提高了数据传输速度,节约了硬件资源。测试结果显示,该系统工作稳定可靠,读写速度...     

基于FPGA的PCIe总线接口的DMA控制器的设计

采用Altera公司FPGA提供的PCIe PHY IP和Synopsys公司提供的PCIe Core IP提出了一种PCIe总线接口的DMA控制器的实现方法,并搭建了4通道的PCIe传输系统。利用Synopsys VIP验证环境对系统进行了仿真验证,利用Altera Stratix V EX系列FPGA搭建平台进行了实际传输验证,验证了数据读写的正确性,在进行DMA读写事务操作时总线带宽峰值分别达到了1 547 MB/s和1 607 MB/s,能满足大部分实际应用中对数据传输的速率要求。     

基于PCI总线的高速数据传输

本文通过PCI总线I/O加速器PCI9054,利用DMA方式实现了高速数据传输。详细介绍了两种主要的DMA方式,PCI9054内部相关寄存器的配置以及DMA的数据操作流程,并根据本地信号状态机,在FPGA里设计本地信号控制器,实现了计算机高速读取PCI设备内的数据。     

PCIExpress专用DMA控制器设计与实现

针对PCIExpress设备用户端较难充分利用PCIExpress高数据带宽的问题,文中使用硬件描述语言设计了一种专用于PCIExpress设备数据传输的高性能DMA控制器。该DMA控制器与PCIExpress事务层直接连接,可以适用于Genl到Gen3不同协议版本;用户端接口具有较高的通用性和扩展性,可高效的并发完成多个系统到卡（S2C）和卡到系统（C2S）的DMA操作。该DMA控制器的设计经过RTL仿真、FPGA验证,功能正确,工作稳定。测试结果表明,该DMA控制器对PCIExpress带宽的利用率超过62％,达到了设计预期目的。     

基于PCI总线的DMA方式高速数据传输

本文通过PCI总线I／O加速器PCI9054，利用DMA方式实现了高速数据传输。详细介绍了两种主要的DMA方式,PCI9054内部相关寄存器的配置以及DMA的数据操作流程，并根据本地信号状态机，在FPGA中设计本地信号控制器，实现了计算机高速读取PCI设备内的数据。     

PCI Express 专用 DMA 控制器设计与实现

针对 PCI Express 设备用户端较难充分利用 PCI Express 高数据带宽的问题,文中使用硬件描述语言设计了一种专用于 PCI Express 设备数据传输的高性能 DMA 控制器.该 DMA 控制器与 PCI Express 事务层直接连接,可以适用于 Gen1到 Gen3不同协议版本;用户端接口具有较高的通用性和扩展性,可高效的并发完成多个系统到卡(S2C)和卡到系统(C2S)的 DMA 操作.该 DMA 控制器的设计经过 RTL 仿真、FPGA 验证,功能正确,工作稳定.测试结果表明,该 DMA 控制器对 PCI Express 带宽的利用率超过62%,达到了设计预期目的.     

基于IP核的PCI Express接口

提出一种基于IP核的PCI Express接口设计方案,采用分层的体系结构,具有高性能、高可靠性、软件兼容等特点。在Xilinx公司的xc5vlx30t FPGA器件中,运用PCI Express硬核端点模块,设计并实现了PCI Express总线接口,同时在接口内部设计了DMA控制器。仿真实验结果表明,该接口能够有效提高总线的数据传输速率,充分发挥总线的性能。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate