The Design And Implement Of Usb Bus Signal Analysis System

With the popularity of personal computers, USB has become a standard computer interface. USB is due to the complexity of the protocol itself, the development of USB interface device for developers is a great challenge. In order to find the root of the problem, developers must have a certain amount of test and measurement tools for the development of every aspect of qualitative and quantitative analysis. In general, in addition to conventional tools, USB protocol analysis tool is needed to develop USB interface to help to analyse the errors and problems about the protocol encountered during the development of USB interfaceIn order to solve a wide range of issues encountered in the development of the USB interface fundamentally, this thesis gives a whole new USB protocol analysis: To monitor the status and signal of the USB bus, to analyse the packets of each USB interface, and to display the result in the form of visualization, so that the users quickly target and solve problems.The main points of research are as follows:1. CPLD logic design: how to make use of hardware programming language to deal with USB data streams, including the conversion of the state of USB bus, the bus speed of identification, DPLL(Digit Phase Lock Loop), reliable reading data (interference), the remove of bits, and the conversion from the parallel to the serial, the generation of writing signal, and timers.2. Hardware circuit analysis and realization of the demand. As USB 1.1 specification supports low speed (1.5Mbps) and full speed (12Mbps), the hardware circuit must be able to support both speeds and can automatically identify.3. The demand analysis and algorithm realization of the analysis software. Due to the complexity of the USB protocol, the USB packet analysis is a very complex work. In addition to the standard USB requests, USB Implementers Forum has also developed more than 30 categories of class specifications, in particular, these types of class specifications will be continued to update and new class specifications will be added. These class specifications can be added into the analysis software step by step as needed, but the complexity must be taken full account when analyzing the demand.4. Simulation and debug. Debugging the various components respectively, and then testing the function and the performance of the whole system. Due to the complexity of the USB protocol, the debugging process will be very complicated, the choice and generation of test data will be the difficult part.The subject of this innovation lies in the point:1. According to the USB1.1 specification, combining our needs, given the practical USB framing algorithm.2. In the high speed robust environment, with the dual-port memory, the cheap slow speed micro-controllers can be chosen. 3. Based on modular design technology, the analyzing software will support the new class specifications launched constantly.