Design And Implementation Of High-Speed USB Embedded Host System

USB (Universal Serial Bus) is a very important kind of communication bus and has been widely used. For example, the external devices of computer, such as mouse, keyboard, flash disk, portable hard disk, printer, digital camera, mobile phone, scanner, emulator, mobile CD-ROM, USB mike and PC camera are connected to the computer via the USB interface. It experiences Rev1.0, Rev1.1 and Rev2.0 specifications, and now Rev3.0 has also been released. Devices which comply to USB3.0 are being developed. Now the USB support three kinds of transfers which are low speed (1.5Mb/s), full speed (12Mb/s) and high speed (480 Mb/s), respectively. The transfer speed of USB3.0 is 4.8Gb/s, so it will be used more widely when it is developed.In this dissertation, we introduce a kind of DSP-based high speed USB host system. The USB host system supports low speed, full speed and high speed transfers. The main controller of the host system is ADSP BF531 and the USB host chip is ISP1760 which supports high speed and complys to USB2.0. BF531 controls the ISP1760 as its external asynchronous memory. In order to improve the efficiency of the code execution, we use assembly language to program the low-level driver, USB mass storage class protocol, SCSI commands and FAT32 file system. Also, we can create, delete, read and write files which are on the flash disk or portable hard disk. The highest speed of reading data is 22.5MBytes/s and highest speed of the writing data is 15Mbytes/s.