| Peripheral bus, which provides the interface for system host and devices,is one of the most important parts of embedded systems.Traditional peripheral buses are not applicable to embedded systems.The merge of computing and communication is the basis of USB design.The benefits of USB,such as high performance,ease of use,true plug and play,and reduced overall system cost,are just a few of the reasons this technology becomes more and more popular in embedded systems.The paper research into the design of embedded USB host, which includes USB transfer scheduler degsign and the implementation of virtual root HUB driver.The driver of this paper is based the borad that use W90N745 as the controller, and UTi1201 as the USB dual controller. The operation system of the board is uCLinux-2-6.9.UTi1201, the interface chip of UTI host device, compatible with USB2.0, support standard USB devices, makes the host has many USB device functions. The HCD drivers support those devices very well; this make the goal that mentioned previous comes true.Firstly, This paper analyse the USB2.0 specfication, The virtual root hub of USB Host Controller based in embedded system, transfer scheduling, and the operation model of UTi1201,compete the stransfer scheduler of USB Host Controller, and the interrupt routine, and so on. The design of scheduler is the main job of the USB Host Controller Driver. Secondly, I design the root hub driver of UTi1201 after analyse the emulation function of HUB. Thirdly, in the last I introduce the work that have been done of the Gadget Driver. Finally, this paper also analyse the UHCI driver in Linux Kernel, and the USB subsystem of Linux, EHCI specification.The work has been completed, works with the USB device drivers of Linux and other programmes in Linux, the HCD driver can support lots of devices,such as flash dist, USB mouse, USB keyboard and the UTI card of Uintend Corporation. The driver fit the requirement of the Corporation.The speed of the driver is four times of the driver of S3C2410 (approviately 100Mbps). The driver work stably, no date missed. |
