Abstract:
The USB stands for Universal Serial Bus it is a very popular interface in recent computer systems. USB replaces legacy interface, such as serial port, parallel port, and so on. Every recent PC and Macintosh computer includes USB ports that can connect to standard peripherals such as keyboards, mice, scanners, cameras, printers, and drives as well as custom hardware for just about any purpose. The aim of this work is to develop a USB interface that can be used to transfer data. The interface is the bridge which allows data transfer from one side to other one. Presented work is exploring an application area of FPGA to develop an interface design on FPGA. The interface is multi-purpose so that the data can be traveled in both the direction. This work describes the implementation of USB 1.1 low speed interface in FPGA chip, using VHDL programming at Xilinx ISE 7.1 i platform supported by Aldec Active HDL simulation environment. The design is targeted to make a feel of an original USB device which is sending or receiving data from USB port. the design contains the data lose protection and synchronization mechanism, in USB the data travels in the form of packets , there are three type of packets Token, Data and Handshake , the interface takes care of all the three packets and there inner contents. Due to the limit of clock frequency the design can show only low speed transaction so only USB 1.1 specifications are discussed here
