数据总线

CAN field-bus is a kind of serial communication network, which supports distributed control or real-time control effectively. Because of its excellent characteristic and high reliability, CAN field-bus is highly thought of by industries. As the main data channel, 1553B field-bus relates various subsystems that are included in the integrated electronic system of avigation. Due to its excellent performances, 1553B field-bus has been widely applied in avigation, spaceflight, navigation and other weapon equipment.

CAN现场总线是一种有效支持分布式控制或实时控制的串行通信网络，具有卓越的特性和极高的可靠性，受到工业界的高度重视。1553B现场总线作为航空电子综合系统中各子系统之间交联的主要数据通道，因其性能优异，已在航空、航天、航海和其他装备上得到广泛的应用。

It was used field bus technology according to the characteristic of ocean buoy.

根据海洋浮标的特点，运用现场总线技术，设计了基于CAN总线的浮标数据采集系统。

Since the motherboard with the soft, hard disk, such as the use of DMA operations between the peripheral, DMA operation of the response process is as follows (AST386 in the floppy disk to DMA as an example): floppy disk drive made by DREQ2 signal to the DMA controller (82C206), and DMA controller to the CPU (80386) issued HRQ signal, CPU end the current bus cycle after HLDA response signal to the DMA controller, DMA controller issued a final response signal DMA to the floppy disk drive DACK2 allow its data into the system bus.

由于主板与软、硬盘等外设之间采用DMA操作，DMA操作的应答过程如下(以AST386中软盘DMA为例)：先由软盘驱动器发DREQ2信号给DMA控制器(82C206)，然后DMA控制器向CPU(80386)发HRQ信号，CPU结束当前总线周期后发响应信号HLDA给DMA控制器，最后DMA控制器发DMA响应信号DACK2给软盘驱动器允许其数据进入系统总线。

Lastly, this paper introduces the concept of data service bus, and explains its important role in system integration.

最后，引入数据服务总线的概念，对总线的作用进行了阐述。

The paper introduces the hardware structure and software design of CAN bus data communication system, including the operating principle and the application in the system.

本文详细介绍了基于CAN总线的数据通信系统的硬件架构和软件设计，包括CAN总线的工作原理和其在系统中的应用。

But the bits to bits arbitration of the CAN protocol defines a static priority to messages exchanged. Due to the fact of the lack of timing information for non periodic data transmission, it is impossible to find a static manner to attribute CAN identifiers to exchanged objects so that applications periods limit can be always be satisfied. When one or many network stations send data using the same identifier, at some point, data will differ and generate error. All stations will then back off and retransmit restarting the whole process. In this case, retransmission can lockup the network.

然而， CAN总线采用位仲裁技术，利用信息的标识符域定义了一种静态的优先权，由于非周期数据传输时缺乏时间信息，不可能找到一个静态标识符分配方案永远满足应用程序对时间的要求；当一个或多个网络节点同时发送标识符相同的数据时，如果数据不同，所有节点都要重新发送数据，在这种情况下，网络将阻塞。

The control software connects with PCI driver to send order to the measurement system, in order to initialize the system and start collection. It will access the time domain data in RAM and frequence domaim data in DSP through PCI bus, finish data transfer automaticly, display the data in many ways such as graphicness and table, and store the data into harddisk at the same time.

总控软件与PCI驱动程序挂钩，向测试系统发命令，实现系统的初始化和启动采集等动作，并通过PCI总线读取RAM中的时域数据和DSP中的频域数据，自动完成数据转换，以图形和表格等多种方式实时显示被测参数，并在显示的同时将数据存储到硬盘中去。

According to the calibration information, Research and development status of automotive bus network and automotive calibration system is studied and the research significance is generalized. First of all, the collectivity precept for calibration system is designed, the calibration platform is set up based on the XCP Protocol and the calibration object is CAN bus network simulation ECUs. Then how to create the calibration system based on Ethernet and Series communication is expatiated, the communication way from computer to ECUs is introduced and the calibration system is tested. Then how to create the calibration system based on CAN bus communication is expatiated, the design and the interface programme are introduced and the calibration system is tested. At last the platform is used to calibrate the CAN bus network simulation system to regulate the simulation system's topology and communication speed to test the communication protocol's feasibility.

论文首先设计了标定系统的总体方案，以CAN总线实时仿真系统中的节点标定为研究对象，采用XCP协议建立具有串口、以太网和CAN总线三种通讯接口的标定平台；然后，具体开发了基于以太网通讯和基于串口通讯的标定系统，完成了上、下位机部分的软件设计，确定了标定系统在两种通讯方式下的数据处理方法，并分别应用两种标定方式标定下位机仿真系统的参数，让下位机仿真系统在规定的通讯协议和拓扑结构下进行仿真，对所设计的标定系统进行了调试；接着，设计了基于CAN总线通讯的标定系统，完成了CCP协议（&XCP on CAN&）的接口程序设计，并通过混合动力汽车一种拓扑结构的通讯仿真对所设计的系统进行了调试；最后，应用开发的标定系统，对混合动力电动汽车网络通讯协议进行了仿真研究，并根据实验结果进行了分析。

Hardware circuit include process channel module based upon 1-wire, communication module based upon CAN feus, data store module based on I2C bus, human-computer interaction module, I/O extended module and so on.

硬件电路包括基于1-Wire单总线的过程通道模块、基于CAN总线的通信模块、基于I~2C总线的数据处理模块、人机交互模块、I／O口扩展模块等。

A portable field information acquisition system is designed based on single chip,nonvolatile memory chip, GPS and several kinds of sensors. It can gather and recordthe information of GPS, sensors of field information acquisition and display them byLCD.

该系统可以同时采集和记录GPS、土壤水分、养分、温度等多种传感器的数据，通过液晶显示屏现场即时查看数据、记录数据；用户可将采集记录的数据通过USB总线或者串口发给微机，在微机上形成Excel表格或者文本文件，方便用户进行数据分析。3。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。