由于在USB 系統中，USB 設備之間的數據交換必須通過主機。而扮演主機角色的一
般為個人電腦。由于個人電腦的攜帶不便造成USB 設備間數據交換的不便。本文主要設計并實現一個可集成在便攜、移動產品上的USB 控制器。它可以通過OPB 總線接口集成到一個嵌入式系統中，并能與USB 設備進行正常的通訊。本文主要設計并實現了USB 控制器，詳細介紹了總線接口、邏輯控制部分、物理接口、數據的存取等部分。
關鍵字: USB；控制器；OPB；接口
Abstract: In the USB system, it always uses the master machine to realize the data exchange
between USB equipment. Mostly, the PC is used as this master machine. Consequently, the data exchange between USB equipment is not convenient. This paper designed and implemented a USB host controller soft core that can be used in mobile devices. The USB host controller core can be integrated in an embedded system through OPB interface，and can communicate with USB device successfully. The logic design and realization of the USB host controller is introduced next, including OPB BUS interfaces, logic control, and physical interface, read and write data, etc.
Keywords: USB; Controller; OPB; Interface