The Design And The Implementation Of USB 1.1 Interface Circuit In Microprocessor

At present, USB 1.1 has been widely accepted as standard of personal computer and peripheral devices which has been applied to various kinds of devices. Comparing to other communication interface, the most advantages of USB interface is its feasibility, Plug and Play supporting, and automatic configuration without user's disturbance. Embedded system is special computer system, which is focused around applications and based on computer technology.It is composed of scalable hardware and software. And it should be content with the need of function, reliability, cost, size and consumed power.The USB interface circuit is designed for the microprocessor for the HPC .In the paper, the background of the USB interface circuit is firstly introduced. And three design goals of it is created.Complies with Universal Serial Bus specification 1.1Support Mass storage classProvide parallel bus interface to userIn the light of the goal, the general scheme is formed. The paper illustrates the design goal of the interface circuit, the interconnected structure and the scheme of software and hardware. In the frame design of hardware, the two scheme(DMA transfer and interrupt transfer) are illuminated.Comparing the two scheme, we selecte the scheme of DMA transfer. In the verification of design, USBVIP OF SYNOPSYS is used. In the design of USB device-end driver sofrware,device enumeration is described particularly.Comparing the readcard based on the USB subsystem to the readcard on the market, we assure that the USB subsystem can fulfil the design goal.Afer we sum up the design of USB interface circuit, we sugguest that the system evlauation is accomplicated at the beginning of design to avoid the risk of design.