Usb Protocol Stack And Hin On The Component-based Research

The paper is based on prat ice in that the author joined development o(' ElastOS with independent propoty right in Koretide Corp. The author's task is grafting rock-bottom code on USB of FreeBSD, designing USB stack in ElastOS component ly. After understanding USB stack and ezCOM technique in detail, the author succeeded in developing USB stack. At present, it is successfully used at two-dimension indicating number identification terminal in Fujian Landstanding Electrics Technologies Corp.The paper firstly represents some lores on USB system. USB is a kind of specificat ion of computer connected peripherals. It has the merits of PnP, reiiable data transfer expanding expediently, low cost and so on. In the field of Embedded System, it is applied widly.ElastOS is a late-model arcgutectibuc Embedded Operation System which applies with ezCOM technique. ezCOM comes form COM, solves some details of developing COM componet and adds some new characteristics.At last, the paper presentes briefly how to design USB stack on ElastOS, included USBD, HCD and Client Driver(Mouse Driver). At the base of grafting successfully and understanding USB code of FreeBSD, the author compartmentalizes the module of USB, defines the interfaces and realizes every module as an absolute component.