Research Of Function On Embedded USB HOST And OTG

USB is a high-speed, low-cost, plug-and-play bus technology, and has a wide range of applications. But the USB must strictly comply with master-slave structure, the HOST plays a central location, every USB data transmission must be initiated by the host, while the substantial role to playing the host is PC in reality。Along with the rapid development of the current electronic information technology, USB technology has used in the industrial equipment, home appliances, communications products and other fields, it is hoped that these devices can be separated from the PC and communicate with peripherals directly through the USB interface. With the popularity of embedded products, the demand of USB HOST is more and more obvious, both at home and abroad advanced manufacturers have also begun to look towards embedded USB HOST technology.This papers focuses on satisfing to needs of the embedded systems and portable electronic products for the USB equipment, and first analyzes architecture and features of USB technology, including industry-standard bus, topology, protocol definition and transmission methods; Simultaneously analyzes the norms, equipment type, systems and driver architecture of USB OTG and so on; then introduces in detail a achieved approach of USB HOST system: Combinated of existing embedded operating system uCLinux transplant technology, used of high-performance, high scalability and multi-functional ARM processor S3C44B0X and SL811HS chip of realizing host controller function, designs and realizes USB HOST Function. And introduces hardware accordancing with the choice of chips, functional blocks and circuit design, in particular, describes in detail S3C44B0X processor and SL811HS host controller chip. In software, the papers mainly discusses USB HCD, USBD, agreement of USB Mass Strage Class and the corresponding file system. In the system design process, the papers describes in detailed the focus of attention of each part and the realized difficulties, the relevant developers have a certain degree of referential significance. Finally doing a summary and analysis about this system design, and forecasts the development and application prospect of embedded USB HOST system.