共查询到15条相似文献,搜索用时 109 毫秒
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TTCAN协议是一种CAN总线高层协议.在现行CAN协议的基础上引入了时间触发机制.在遵循TTCAN协议的CAN通信网络中,总线活动可以用时间或者事件两种方式进行触发.介绍了TTCAN协议的提出和发展过程,阐述了协议中基于基准消息和网络时间实现时间触发的机制、不同TTCAN网络之间的时间同步以及TTCAN协议的硬件实现. 相似文献
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为解决CAN总线系统中事件触发报文发送时,固定优先级仲裁机制所引起的发送时间不确定,低优先级报文可能被延误的问题,根据时间触发CAN的基本原理和结构特征,结合通用CAN控制器SJA1000,举例介绍如何组建一个TTCAN实验系统的基本步骤和算法。该设计可以确保实时和安全性要求较高的自控系统的正常运行。 相似文献
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CAN总线的时间触发调度方法及实验研究 总被引:6,自引:0,他引:6
借鉴TTCAN总线时间触发机制和静态调度特点,利用微控制器的硬件周期中断,结合软件编程,提出一种充分利用了CAN 2.0 总线位仲裁特点的时间触发方案,并对以该方案进行数据传输时的总线带宽利用率和传输误码率进行了模拟实验研究.结果表明:将CAN总线和微控制器的周期中断相结合,可以利用CAN 2.0 总线实现时间触发型应用,并获得较高的带宽利用率,该方案可应用于分布式数据采集系统等传输大量周期数据和少量非周期数据的场合. 相似文献
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CAN总线是在工业控制领域普遍使用的著名现场总线。为了使CAN总线可以应用于有严格实时要求的工业控制场合(例如安全性自动控制装置),爱尔兰的Limerick大学正在研制一种具有确定消息传输行为的、时间触发的CAN总线。本文介绍事件触发和时间触发的概念,以及TTCAN的主要特点。 相似文献
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TTCAN 作为建立在时间触发机制上的标准CAN协议的高层协议,已逐渐成为广泛应用于汽车局部网络的通信协议.同时,基于软件仿真模型的开发方法也正在被汽车工业和研究领域所采用,以提高产品质量,减少开发成本.为了缩短TTCAN网络应用系统的开发周期,该文应用面向对象的开发方法建立了TTCAN协议的软件仿真模型.该文首先分析了TTCAN协议特点,然后详细描述了建立和实现TTCAN协议的软件仿真模型的过程,在仿真模型中,对TTCAN网络中各节点之间数据的发送、接收以及时间触发机制进行了模拟,最后给出了仿真结果. 相似文献
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对TTCAN的分析 总被引:3,自引:0,他引:3
杨福宇 《单片机与嵌入式系统应用》2008,(6):5-7
TTCAN通过独占窗口的方式解决消息传送的确定性问题,提高总线利用率,试图满足应用发展的要求。但是在恶劣环境的高误码率下,传送的可靠性下降,容错的措施不成熟,成本较高。再考虑TTCAN的其他得失,认为它不是性价比高的CAN技术升级方案。 相似文献
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针对矿用新能源电机车CAN节点发送错误造成关键信息丢失的隐患,在TTCAN协议的基础上提出了CAN总线发送容错方法,即对CAN节点发送失败的报文重新发送,当发送成功或者达到预设的最大重发次数后退出该报文的发送;给出了一种CAN总线高效接收、处理报文方法,在中断接收报文期间对报文进行缓存操作,同时修改接收到的报文数量,主程序以此为依据逐条对存放在缓冲区的报文进行后续处理,实现了报文接收与处理的分时操作。测试结果表明,该优化方法可有效提高CAN总线通信的实时性和可靠性,同时减小了各CAN节点CPU开销,提高了工作效率。 相似文献
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This paper discusses aspects of dependability of real-time communication. In particular, we consider timing behaviour under fault conditions for Controller Area Network (CAN) and the extension Time-triggered CAN (TTCAN) based on a time-driven schedule. We discuss the differences between these buses and their behaviour under electromagnetic interference. We present response timing analyses for CAN and TTCAN in the presence of transient network faults using a probabilistic fault model where random faults from electromagnetic interference occur. The CAN analysis provides a probability distribution of worst case response times for message frames. The results indicate that CAN may generally provide a higher probability of delivering messages on time than TTCAN. The CAN analysis result is used to discuss an approach to implementing a bus guardian for event-triggered systems.Ian Broster is a research associate at the University of York, his research includes real-time communication and work on the CAN protocol. Current research focuses on next-generation flexible scheduling for real-time operating systems. His research interests include probabilistic analysis, timing analysis of non-deterministic systems, flexible scheduling, real-time communication, simulation and modelling. He received his M.Eng. degree in 1999 and a Ph.D. in 2003 for his work on flexible real-time communication at the University of York, U.K.Alan Burns has worked for many years on a number of different aspects of real-time systems engineering. He graduated in 1974 in Mathematics from Sheffield University; he then took a D.Phil, in the Computer Science Department at the University of York. After a short period of employment at UKAEA Research Centre, Harwell, he was appointed to a lectureship at Bradford University in 1979. He was subsequently promoted to Senior Lecturer in 1986. In January 1990 he took up a Readership at the University of York in the Computer Science Department. During 1994 he was promoted to a Personal Chair. In 1999 he became Head of the Computer Science Department at York.Guillermo Rodríguez-Navas holds a degree in Telecommunication Engineering by the University of Vigo, Spain. He is currently doing a Ph.D. in Computer Science at the University of the Balearic Islands, Spain. He is also a member of the System, Robotics and Vision (SRV) research group at this university. His research is focused on dependable and real-time distributed embedded systems. In particular, he has addressed various issues related to the Controller Area Network (CAN) field bus, such as fault tolerance, clock synchronization and response time analysis. 相似文献