Research And Design Based On USB Mass Storage For MCU

Universal Serial Bus by way of a new type of computer bus has the characteristic of Plug and Play, hot plug capability, small interface cubage, etc. All of these will bring overturn to the technic of computer interface. The research and design of embedded USB system will broaden the applied field of USB interface technic, and bring the brand-new world of the design of embedded system. USB system includes two subsystems: USB host and USB slave. Technic of development on USB slave system and USB host system based on PC has been already very maturity, however, implement of USB host system based on embedded system encountered many difficulties because of abundant resources on the PC and limited resources on embedded system. How to apply USB to embedded system and realize USB interface has became the hot of USB research field now. In this article, by analyzing the USB protocol and communication flow, the software and hardware qualifications the embedded USB host needs to have is confirmed, without any support of the OS (Operating System). Using the wildly used flash disk as USB facility, in virtue of the CYPRESS USB interfacing chip SL811HS, the MCU (Micro Controller Unit) is also able to accomplish the operation to flash diak without supporting by OS. Consequently, this article provides a new practical solution for applying USB technic into the embeeded system. The primary task of this article as follows: 1. Introduce the USB Bus, analyze USB protocol and embedded host's function. 2. Introduce the USB device genus (Mass Storage) and how to realize the USB interface in the embedded system. 3. Design the experiment model of MCU+USB interface chip and complete the design of hardware. 4. For the software requirement of the USB host, we have programmed in MCU system in order to realize USB protocol stack, USB mass storage protocol and FAT files system wildly used in PC field. The program design is also explained in details combining with flow chart.