USB通信研究及其在虚拟仪器中的应用设计

范文编号:TX033       范文字数:23415,页数:51

摘   要
随着计算机技术、通信技术和多媒体技术的发展以及计算机应用的普及，计算机系统的外围设备越来越多，这些设备并没有统一的接口标准，设备的安装和配置都比较复杂。而相对于外设种类和数量的增多，PC机传统接口从系统与用户两个角度都呈现出其固有限制。在此背景下，已成为PC标准的通用串行总线USB为多点数据采集提供了很大的便利，利用USB可以实现较传统方式更有效、更经济、点数更多的数据采集。采用USB接口的设备无一例外地支持热插拔（带电插拔），用户在开机状态时即可将设备连接到电脑主机上，免除了使用户感到厌烦的重新启动过程。USB1.1规范中规定了两种传输速率，全速方式的传输速率为12Mb/s，低速方式的传输速率为1.5Mb/s。因此，USB总线接口与其他类型的接口相比，其优越性就体现在这里，它的传输适合各种类型的外设，并支持热插拨。本文介绍了USB接口的开发方法和流程，从而实现了利用USB接口来实现多点数据采集。在设计中采用的USB芯片为PDIUSBD12，它通常用作微控制器系统中实现与微控制器进行通信的高速通用并行接口，它支持本地的DMA 传输。另外在接口的软硬件设计上介绍了接口电路的连接和固件以及驱动程序的编写，着重介绍了设备驱动程序的开发方法和过程。本设计中采用的“USB接口芯片+传统单片+功能电路”的模块化设计方法，具有很高的灵活性，从而能减小开发的时间、风险以及费用（通过使用已有的结构和减少固件上的投资），从而用最快捷的方法实现最经济的USB外设的解决方案。通过以上优点，我们可以看出USB接口是作为通信接口的一个理想选择。
关键词： USB；PDIUSBD12；AT89C52；USB驱动；Windows DDK

Abstract
With the development of computer technology, corresponding technology and multimedia Technology, and the popularization of the use of computer, the computer system peripheral equipment becomes more and more. The equipment does not have unified standard of interface, installation and disposition of the equipment are more complicated. Comparing with the increase of the kinds of peripheral equipment and quantity, the PC traditional demonstrates their inherent destructiveness from system and user these two angles. Under this background, the serial bus USB in common use, which has become PC standard, has offered great convenience to the gathering of multi-point data. Utilizing USB can realize the datum gather, which is more effective, more economic, than the traditional way. The equipment adopting USB interface supports not plug without exception and the user can connect the equipment to the host computer, while the machine is working, having avoided the course of restart. Which is fed up by the user USB1.1 has stipulated two kinds of transferring rate, in a norm: the transferring rate of the full-speed way is 12Mb/s, and that of the low-speed is 1.5Mb/s. So, compared with interface of other types, the bus interface of USB’s inferiority embodies in here. Its transmission is suitable for all kinds of peripheral equipment, supporting hot plug. This text has the development approach and procedure of USB interface, thus realized the gathering of multi-point data by utilizing USB. The USB chip adopted in the design is PDIUSBD12.It’s usually used as the high speed parallel interface in common use to realize the communication with little controller in the little controller system, and it supports the transmission of local DMA, having introduced the development approach and course of the equipment driver procedure emphatically in the design of software and hardware of the interface in addition. The “USB interface chip + traditional single piece + functional circuit' module design method adopted in this design. Has high flexibility, which can reduce the tine of development, the rislc and expenses, thus can come to the solution of the most economic USB peripheral, hardware with the swiftest method. Through the advantages above, We can find out USB interface is an ideal of the communication interface.
Key Words:  USB；PDIUSBD12；AT89C52；USB DRIVER；Windows DDK

目    录
1  绪论   1
2  USB1.1规范和协议概述   2
2.1 USB物理连接   2
2.2 USB系统拓扑结构   3
2.3信号编码   3
3  USB通信原理   4
3.1通信结构   4
3.2 USB传输类型   4
3.3 USB通信流模型   5
3.4 USB传输协议   5
3.4.1包的组成   5
3.4.2包的类型   6
4  USB接口设计总体方案   8
4.1 接口芯片选择   8
4.1.1 AT89C52芯片简介   9
4.1.2 PDIUSBD12接口芯片简介   9
4.2 通信接口原理方框图   14
4.3具体硬件电路设计   14
5  USB微控制器固件编写   17
5.1固件编写模型   17
5.2 USB通信处理   18
5.3固件编写实现   19
5.3.1中断服务程序流程   19
5.3.2 标准设备请求处理   23
5.3.3 主循环程序流程   26
5.3.4 主要程序说明   26
6  USB驱动程序编写   30
6.1 WDM驱动程序模型   30
6.2 几个重要数据结构   31
6.2.1 DRIVER_OBJECT(驱动程序对象)   31
6.2.2 DEVICE_OBJECT（设备对象）   31
6.2.3 IRP（I/O请求包）   32
6.2.4 IO_STACK_LOCATION(I/O堆栈)   32
6.3驱动程序中的主要例程   33
6.3.1 DriverEntry例程   33
6.3.2 AddDevice例程   33
6.3.3 IRP处理例程   34
6.3.4 即插即用管理   34
6.4  USB驱动程序栈   34
6.5配置USB设备   35
6.5.1设备描述符   35
6.5.2配置描述符   37
6.5.3接口描述符   38
6.5.4端点描述符   38
6.5.5 USB串描述符   39
6.5.6完成配置   39
6.5.7取消配置   40
6.6 USB设备访问   40
7  应用程序设计   41
7.1 获取设备信息集   41
7.2 识别接口信息   41
7.3 获得设备路径名   41
7.4 打开设备   42
7.5 读写USB设备   42
7.6 关闭通信   42
8  调试   43
9  结论   44
致谢   45
参考文献   46

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