Design And Realization Of USB Host Interface On Digital Set-Top-Box

Nowadays, along with the maturation of USB (Universal Serial Bus) technology in PC, the exchange and storage of mobile data has recently become a hot focus in IT fields. USB is the medium of data exchange as well as the kernel mechanism of dada exchange. Along with the spread of USB application, the industry has introduced USB to the non-PC field , namely embedded system field.Therefore,the realization of embedded USB Host interface has become a hot topic in nowadays electronic world.In this background and trends, this paper discussed on how to design and implement embedded USB host interface on digital Set-Top-Box, and accomplish the mass storage and fast data exchange between U disk and Set-Top-Box, which meets the true requirements as a multimedia platform.First of all, this paper introduces the principle of digital TV,digital Set Top Box and USB bus protocol,including a brief presentation about USB bus topology, USB communication principle ,USB device and host and so forth, while analyzing contrastively two kinds of primary research methods about the current USB host interface design:(l) USB host controller + CPU, (2) (USB host controller + MCU) + CPU.After considering the two kinds of schemes synthetically, scheme (2) was adopted to implement our USB host interface. Secondly, this paper introduces some principles about the selection of USB host interface chip, and selects Cypress's SL81IHS to act as USB host controller interface chip to build the experiment model of MCU+SL811HS Host interface+Dual-port RAM and completes the design of hardware.Then this papaer make instruction in detail about some chips.Furthermore, the realization of USB protocol stack software system was probed into,which is the difficult and key point of the whole system design. the system actualizes USB host controller driver and USB core driver that is tailored according to USB specification.In view of the U disk equipment, this paper achieves the mass storage protocol after reduction and establishes a simple FAT file system, which can completed to read and write U disk documents.Finally, on the basis of the USB host interface hardware circuit and corresponding driving system that are designed out, this paper completes testing and evaluation of the entire hardware and software system, which focus on analysis the test methods and test target and the system performance results of tests, various kinds of parameters reached the anticipated designing requirement.And then,thinkes carefully about the problems encountered in the entire process of project studies, make a number of recommendations about the further study; In the end,this paper discusses on some relevant upper strata applications, and makes an outlook about the application of this USB host interface in a broader field of embedded system.