Realization Of Virtual Logic Analyzer Based On USB

Virtual instrument (VI for short), which is of a good developed foreground and is widely used in every field of science technology, is a new kind of electronic instrument with electronic measure technology deeply combined with computer technology. Before the appearance of USB technology, many virtual instruments are designed by using computer PCI interface or enhanced parallel port. The emergence of USB2.0 technology brings strong convenience and expansibility to computers. It provides plug and play ability which other interfaces don't have.The logic analyzer discussed in this paper not only uses USB interface, but also uses virtual instrument technology that is widely used recently. The combination of computer, software and FPGA technology makes the logic analyzer get the plug and play ability of USB interface. Particularly, the hardware design is described in this paper. Then the using method and settings of USB interface chip in this system are explained, and many tiger technologies in CPLD are given. At the same time, the technology of lower-speed-storage and timing design in FPGA are discussed, also, some technology difficulties in the design, such as application, driver and firmware are discussed.