USB Device Drivers Research And Design Based On Embedded Systems

USB(Universal Serial Bus) driver development is a cumbersome and complex task. Linux, the USB core subsystem encapsulates the most complex, and provides appropriate support mechanisms. USB protocol specification defines a set of standards that many types of peripheral devices can follow, but for the video equipments, it have not defined the uniformed standard from different manufacturing companies of different devices, and the specific driver need to be developed.In the design and development of USB camera driver based on embedded system, you should make full use of the USB bus bandwidth and ensure a high and stable data transfer speed between memory and peripherals. In order to meet the real-time video capturing requirements, reference had been made to open-source projects GSPCA/SPCA5xx, recommendation of Linux kernel had been adopted, and using double-URB(URB Request Block) strategy and MMAP (Memory-map) mechanism to maximize the video capturing speed, eventually realizes this USB camera driver in line with V4L(Video for Linux) on the S3C2440AL_ARM development platform and provides a functional verification and performance analysis. The experimental results show that the driver can fully meet the embedded video requirements for the general application.