自动化专业——毕业设计——USB转换rs-232转换器设计论文.doc

摘要 通用串行总线(Universal Serial Bus，简称USB)从诞生至今已经十多年了。这十多年问，USB在不断完善，并走向成熟。其成本低、速度快、通用性强、可热拔插等诸多优点，得到了诸多厂商的认可。随着USB应用领域的扩大，如何将USB应用在工业领域，实现USB到标准工业接口(如RS232)之间的双向数据通信，成为新的研究课题。USB系统包括USB主机、USB设备和USB互联三部分，其中USB主机是核心，要想实现USB接口到标准工业接口的双向数据通信就离不开USB主机。因此USB主机的开发是本课题研究的关键。 本文研究的目的就是实现USB主机功能，使USB设备和RS232设备通过本系统能够通信；同时本系统也能够实现USB设备功能，将RS232接口设备能够映射成为USB接口设备。 本文以SST公司的8位处理器89E58RDA为核心处理器，沁恒电子有限公司的CH375B作为USB主/从控制芯片，构建了主动/从动USB通信模块。通过对USB协议的认真研究，深入剖析了USB的系统体系、数据通信模型、数据包格式、USB标准描述符。并且对USB大容量存储设备(Mass Storage)类规范进行了仔细的分析，建立了USB与Mass Storage类设备之间的逻辑通信模型；实现了USB接口到RS232接口的双向数据通信。硬件上完成了各模块的原理图；在软件上，完成了系统核心驱动程序、USB主机的通信驱动程序以及设备驱动的设计。 本系统硬件设计方案具有成本低、功耗小、U盘识别率高等特点。 关键词： Mass storage类；SST89E58RDA；CH375B；RS232  Abstract Universal Serial Bus Universal Serial Bus，as USB)from birth has been 1 0 years．Its low cost，high speed，high universality,hot—pluggable，and many other advantages，have been approved by many manufacturers．With the expansion of USB applications，how to use USB in the industrial field，and the communications between USB interface to standard industry interface(such as RS232)，it’S a new study．USB system，including USB host，USB devices and USB connection，and USB host is the core．In order to achieve the communications between USB interface and standard industry interface,the most important is the USB host．Therefore USB host is the key in this Papers． The purpose of this paper is to realize USB host functions，allowing USB devices and RS232 devices can communicate through this system．At the salne time，this system Can realize USB device functions． The core processor is SST89E58RDA,and the USB master/slave control chip is CH375B which Was produced by QinHeng Electronics Co．，Ltd．They construct the active/passive USB communication system．I carefully studied the system of USB，the USB protocol，the data communications model，the packet format，USB standard descriptors，etc．Especially analyze USB Mass-Storage class，and the logic communication model between USB Mass Storage de