Optimized Design of USB Device Controller Endpoint Buffer Regional

Using asynchronous FIFO as a plan to design the endpoint buffer regional of USB is discussed.According to features of the four transfer types of USB,different implementation plans are designed flexible.Especially regarding the particularity of control endpoint transfer,a new type of bi-directional FIFO is presented.Compared with the traditional structure,this program can ensure the circuit area is reduced nearly a half in the function of control transfer.For other types of endpoint design,in order to ensure the transmission speed,double buffering FIFO structure is used,this structure can effective guarantee of the interface transfer speed.The results of ASIC circuit are presented.