Research And Design Of USB Long Distance Optical Fiber Transmission Device Based On FPGA

As we all know, Universal Serial Bus is widely used in the design of electronic products. It supports several features of designed devices, such as fast plug and fast play, hot swap, and flexible application. With the rapid development of USB technology in recent years, the maximum transmission rate of USB3.0 has reached 5 Gbps, from the 1.5 Mbps of USB1.0, the 12 Mbps of USB1.1, and the 480 Mbps of USB2.0, which gives a great support to the development of high-speed electronic products. However, the general transmission distance of traditional USB electric cable is just less than 5m because of the cable loss, limitation of USB protocol, etc., which shortens the application of USB transmission in long-distance area. Thus, it is necessary and of great significance to research and develop the long-distance transmission devices for USB signals.This paper proposed a design solution of a long distance transmission device for USB signals based on FPGA. The designed device in this paper selects the USB 3300 chip(provided by USA National Semiconductor Corporation) as the transceiver module in the USB physical layer. The FPGA in the designed device is to realize the analytical work of part of USB protocol and the data caches work. Then the USB signal is converted by the optical transceiver module, which is for the fiber transmission. In addition, this design solution does not involve the exploitation of complex IP core based on USB2.0. In other words, this design solution is not difficult to achieve.The work detailed analyzed in this paper includes the basic USB2.0 protocol, the FPGA data access process and the development of optical transceiver module. Moreover, the FPGA control program is completed by the Verilog HDL language, while the schematic of the hardware circuit and the design of PCB are completed by the Altium Designer Winter 09. In addition, the interface incompatibility issue between the FPGA module and optical transceiver module is solved by the special TTL to PECL level conversion module. In the end, the test on this long-distance fiber transmission device based on USB2.0 protocol shows a ideal transmission effect, which means this device provide a good guide for the future long distance transmission for USB signals.