Design And Implementation Of A Multi-functional Independent Logic Analyzer

Digital system test is becoming more and more important with the development of digital technology and the wide application. At the same time, due to the integration of digital integrated circuit is higher and higher and the pins of digital chips get more and more,the test of logic signal is becoming increasingly difficult. In testing digital system, we often need to monitor multichannel signals synchronously so as to analyze the timing sequence or compare the logic of signals to acquire the functions and find the fault of circuits. Logic Analyzers can not only detect multichannel logic signals at the same time, but also capture desired signals or time series with a variety of trigger modes. Hence it is one of the most important instruments in digital system analysis and design, and has been widely used in teaching and scientific research.At present, there are two kinds of the commercial logic analyzers. One is a virtual logic analyzer, which uses PC as the processing core and an acquisition device connected with the PC to collect logic signals and send to the PC for storing and displaying. The other is a non-virtual logic analyzer or is called independent logic analyzer, which can work without a PC. Since the independent logic analyzers are always costly, they have not gained popularity in the teaching and scientific research. Therefore, a independent logic analyzer with multiple general functions and low price should have important application value and broad market prospects.This design adopts FPGA as the core controlling device. The processor system is constructed based on NiosⅡ soft core processor, SDRAM controller, DMA controller, time controller and PIO controller, which formed the system hardware platform by combining with USB controller, LCD controller and the LAN controller The system software platform is formed by transplanting μC/OS-Ⅱ operating system and μC/GUI graphical user interface development system into hardware platform.The implemented multi-functional independent logic analyzer has 16 sampling channels. The sampling frequency can be set to 100 M,50M and 20M; Sampling depth is3M* 16 bit; It can be triggered to sample by words, falling edge, rising edge and immediate trigger mode. The multi-functional independent logic Analyzer can control data display format on a 7 inch LCD with the touch screen, and 4 rotary coding switches. On the other hand, it can be controlled by a PC through network or USB interface.