【作者】 王实；

【导师】 刘卫忠；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 作为USB2.0的补充规范,近几年来USB OTG技术也逐渐发展了起来,方便了在没有PC机的情况下,嵌入式设备间的数据传送。而作为数字电视终端接收系统的机顶盒,一方面它的传统存储介质(如flash、EEPROM等)已不能满足新的业务需求。需要设法扩展如硬盘、U盘、Compact Flash磁盘等外接存储媒介。另一方面,机顶盒也不再是一个独立的终端设备,需要与其他设备(IPBOX)进行高速通信在特定环境下协同工作完成任务。针对这一需要,本文在研究了国内外目前USB OTG设计方面的最新进展和相关产品的基础上,探讨了一种针对机顶盒应用的USB OTG接口方案,包括软、硬件的支持。使机顶盒在一次会话过程中,主/从设备身份可以发生更换。作为主设备时能够访问USB外设移动存储设备U盘,对U盘的文件进行读,写,删除,创建,打开。作为从设备时能支持现有USB标准,并响应主设备的指示,完成相应任务。从开通三条通道(上行一条,下行两条),以Bulk方式传输数据。本文首先阐述了该方案所依据的技术背景,包括USB拓扑结构、标准规范以及OTG补充协议内容。然后结合机顶盒系统需求讨论了OTG功能、通信机制等在本研究中的应用,接着分章节详细介绍了系统的软硬件设计。硬件方面首先介绍了所选用的主要芯片和电路整体架构,并详细叙述支持OTG补充协议的外围监控电路的设计。软件方面,首先介绍了程序的整体架构及OTG补充协议栈的设计,最为核心的是SRP和HNP协议的通信转换控制。接着分别介绍了模块在OTG协议栈的控制下分别以主/从设备工作时的程序设计,包括软件的层次、文件系统设计、USB驱动程序以及相应寄存器设置等。最后分析了系统运行的结果,通过进一步测试对性能作出了相应的改善,并列出图表进行了比较。通过实际调试和测试,验证了各项功能。实验结果表明,此USB OTG模块能保证长时间持续而稳定的高速度工作。更多还原

【Abstract】 Advanced as the supplement of the USB2.0 protocol, the USB OTG technique has greatly developed these years. It is very useful to transmit datas between the embedded devices,if there are no host devices like PC. The Set-Up-Box is a kind of the terminal devices of the digital-television. Because of the demand of the new function, nowadays ,the Set-Up-Box can not meet these requirement . It intensely needs to extend the exterior memory medium,like hard disk,USB flash disk,Compact Flash disk and so on.On the other hand, The Set-Up-Box is not independence,and need to be connected with other devices .So they can communicate with each other and work together.To resolve this problem,have studied on the newest progress of the designing of embedded USB OTG interface and relevant products carried out at present, this paper advances and designs a USB OTG module system which can be integrated in the Set-Up-Box .With this modul, the status of the Set-Up-Box can be changed in one transmission.As the host devices,the module can visit the USB flash disk,and sends UFI command which accords with the mass storage protocol. With the FAT file system,the modul can also operate at the files (like read, write, delete, establish, open) in the USB flash disk. As the slave devices,the modul accords with the USB1.1 protocol. So it can respond the request of the host devices, and transmit datas from three pipes in high speed.In this paper, the technological background on which the scheme bases is introduced at first, including the system and the main technique of USB, the supplement of OTG protocol. Then, the design plan of the whole system is discussed, including system requirement, hardware design and communication method. In the latter chapters, the paper deeply dicusses the host and slave part of the modul.It contains the design of the circuit, the framework of the software, the FAT file system, USB driver based on Linux and the design of firmware. At last, system performances test results are gave.更多还原