Based On The Usb Host, Usb-rs232 Interface Converter Is Designed

Universal Serial Bus (Universal Serial Bus, as USB) from birth has been 10 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 same 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 devices. Achieve the two-way data communications between USB to RS232 devices. In hardware, the design of schematic and PCB has been completed. In software, complete the core drivers of the system, USB host of communication drivers and user software. According to the design, I make a sample. Experiments prove that the system is stability.The system is low-cost, small power consumption, and flash storage recognition rate was high.