USB总线体系研究与主从端开发
摘要
USB(Universal Serial Bus通用串行总线)总线是PC体系中的一套全新的工业标准，是由Intel为首的七家公司于1994年11月推出的，专用于低、中速的计算机外设。USB可把多达127个外设同时连到用户的系统上，所有的外设通过协议来共享USB的带宽，并且允许外设在主机和其它外设工作时进行连接、配置、使用及移除。同时USB总线的应用可以清除PC上过多的I／O端口，而以一个串行通道取代，使PC与外设之间的连接更容易。
从1996年2月USB规范版本1.0发布以来，短短几年间，USB不光成为了微机主板上的标准端口，而且还成为了所有微机外设(包括键盘、鼠标、显示器、打印机、数码相机、扫描仪、软驱、光驱、硬盘和网卡等等)与主机相连的标准协议之一。USB1.1规范事实上已成为中、低速设备的标准总线，而2000年推出的USB2.0规范，也有望成为高速设备的标准总线。USB技术和产品正在迅猛的发展中。因此，研究USB总线的体系架构和开发技术很有必要。
本文首先介绍USB的体系结构和特点，包括总线特征、体系结构和电源管理等，接着详细介绍了USB通信协议，包括数据流模型、四种传输方式及各自的特点，以及USB设备标准描述符的定义。接下来论文讨论USB系统的一般开发方法和技术特点。其中第三章以SL811HS芯片为例，介绍了USB主端控制器在嵌入式系统中的开发，详细阐述了芯片特征和软硬件的开发特点；第四章以EZ-USB为例，介绍了一般设备的USB接口的开发技术。结尾部分总结了USB开发的特点和要点。
论文对广大的USB开发人员和技术人员具备较高的参考价值，能帮助开发人员尽快学习掌握USB总线的特点，以及硬件设计和软件编程中的注意事项。
The Universal Serial Bus (USB) is specified to be an new industry standard extension to the PC architecture. It was developed by a coalition of PC industry companies. USB is a serial cable bus that supports data exchange between a host computer and a wide range of simultaneously accessible peripherals. It comes with l.SMbps and 12Mbps(USB 1.1) transfer rate and can support a maximum of 127 devices. Also,USB devices support PnP (plug n play) and Hot plug,which makes it easy to use.
As USB transfer rate is faster compared to serial or parallel port,new device are starting built based on USB interface,such as LAN,keyboard,mouse,joystick,CD-ROM,FDD,printer,scanner,digital camera etc. USB 2.0 specification extends the transfer speed from 12Mbps to 480Mbps,which is exactly 40 times of USB 1.0 or USB 1.1. It is necessary to study the architecture and the development method of this new bus.
In this paper,the architecture and features of USB,including the bus attributes,the protocol definition,types of transactions,power management will be described firstly. It tries to give developers and users a snapshot of USB. Secondly,the thesis discusses the development method of the USB bus:in chapter 3,the USB embedded host controller development will be described,using SL811HS chip;the USB slave development will be described in the next chapter,using EZ-USB chipset. All these chips are supplied by the Cypress Semiconductor Corporation. At last,a summary will be presented as the end of the thesis.
从1996年2月USB规范版本1.0发布以来，短短几年间，USB不光成为了微机主板上的标准端口，而且还成为了所有微机外设(包括键盘、鼠标、显示器、打印机、数码相机、扫描仪、软驱、光驱、硬盘和网卡等等)与主机相连的标准协议之一。USB1.1规范事实上已成为中、低速设备的标准总线，而2000年推出的USB2.0规范，也有望成为高速设备的标准总线。USB技术和产品正在迅猛的发展中。因此，研究USB总线的体系架构和开发技术很有必要。
本文首先介绍USB的体系结构和特点，包括总线特征、体系结构和电源管理等，接着详细介绍了USB通信协议，包括数据流模型、四种传输方式及各自的特点，以及USB设备标准描述符的定义。接下来论文讨论USB系统的一般开发方法和技术特点。其中第三章以SL811HS芯片为例，介绍了USB主端控制器在嵌入式系统中的开发，详细阐述了芯片特征和软硬件的开发特点；第四章以EZ-USB为例，介绍了一般设备的USB接口的开发技术。结尾部分总结了USB开发的特点和要点。
论文对广大的USB开发人员和技术人员具备较高的参考价值，能帮助开发人员尽快学习掌握USB总线的特点，以及硬件设计和软件编程中的注意事项。
The Universal Serial Bus (USB) is specified to be an new industry standard extension to the PC architecture. It was developed by a coalition of PC industry companies. USB is a serial cable bus that supports data exchange between a host computer and a wide range of simultaneously accessible peripherals. It comes with l.SMbps and 12Mbps(USB 1.1) transfer rate and can support a maximum of 127 devices. Also,USB devices support PnP (plug n play) and Hot plug,which makes it easy to use.
As USB transfer rate is faster compared to serial or parallel port,new device are starting built based on USB interface,such as LAN,keyboard,mouse,joystick,CD-ROM,FDD,printer,scanner,digital camera etc. USB 2.0 specification extends the transfer speed from 12Mbps to 480Mbps,which is exactly 40 times of USB 1.0 or USB 1.1. It is necessary to study the architecture and the development method of this new bus.
In this paper,the architecture and features of USB,including the bus attributes,the protocol definition,types of transactions,power management will be described firstly. It tries to give developers and users a snapshot of USB. Secondly,the thesis discusses the development method of the USB bus:in chapter 3,the USB embedded host controller development will be described,using SL811HS chip;the USB slave development will be described in the next chapter,using EZ-USB chipset. All these chips are supplied by the Cypress Semiconductor Corporation. At last,a summary will be presented as the end of the thesis.
引文
[1] Universal Serial Bus Specification Revision 1.1, September 23, 1998, http://www. usb.org
[2] SL811HS USB Host/Slave Controllers Technical Reference,http://www. cypress.com
[3] Universal Serial Bus Specification Revision 2.0, 2000, http://www. usb.org
[4] SL811HS Application Note, 2001, http://www. cypress.com
[5] EZ-USB Technical Reference Manual, Version 1.9,http ://www. cypress.com
[6] Device Class Definition for Human Interface Device http://www. usb.org
[7] SL811HS Specification, 2001, http://www. cypress.com
[8] Human Interface Device support for SL811HS, 2001,http://www. cypress. com
[9] Host Debugger Document, 2001, http://www. cypress.com
[10] SL811HS OTG Application Note,2001, http://www. cypress.com
[11] Universal Serial Bus Still Image Capture Device Definition, Revision 1.0,July 11, 2000, http://www. usb.org/developers/devclass.html.
[12] PIMA 15740:2000, Photography - Electronic still picture imaging -Picture Transfer Protocol (PTP) for Digital Still Photography Devices, First Edition,July 5, 2000, http://www. pima.net/standards/it10/PIMA15740/.
[13] Crans Cant, Windows WDM 设备驱动程序开发指南，机械工业出版社，2000
[14] 肖踞雄，USB系统结构与应用设计，单片机与嵌入式系统，2001
[2] SL811HS USB Host/Slave Controllers Technical Reference,http://www. cypress.com
[3] Universal Serial Bus Specification Revision 2.0, 2000, http://www. usb.org
[4] SL811HS Application Note, 2001, http://www. cypress.com
[5] EZ-USB Technical Reference Manual, Version 1.9,http ://www. cypress.com
[6] Device Class Definition for Human Interface Device http://www. usb.org
[7] SL811HS Specification, 2001, http://www. cypress.com
[8] Human Interface Device support for SL811HS, 2001,http://www. cypress. com
[9] Host Debugger Document, 2001, http://www. cypress.com
[10] SL811HS OTG Application Note,2001, http://www. cypress.com
[11] Universal Serial Bus Still Image Capture Device Definition, Revision 1.0,July 11, 2000, http://www. usb.org/developers/devclass.html.
[12] PIMA 15740:2000, Photography - Electronic still picture imaging -Picture Transfer Protocol (PTP) for Digital Still Photography Devices, First Edition,July 5, 2000, http://www. pima.net/standards/it10/PIMA15740/.
[13] Crans Cant, Windows WDM 设备驱动程序开发指南，机械工业出版社，2000
[14] 肖踞雄，USB系统结构与应用设计，单片机与嵌入式系统，2001