Development Of Multi-channel And Reconfigurable Virtual Logic Analyzer

In 1973,HP cooperated with IBM to develop an instrument which was used to test the logical relationship between a number of digital signals.Then as a general instrument to be popularized,and gradually developed into a logic analyzer.It is mainly used for the display,analysis and processing of digital signals.It is widely used in digital circuit design.The logic analyzer includes time series analysis and status analysis,which is distinguished by internal or external clock when data acquisition.Depending on the rich trigger function,we can locate the error point in the data streams.It is consists of acquisition module,memory controller module,master controller module,transmission module,display module and so on.Due to the stand-alone version of the logic analyzer is so expensive that the using of the threshold is too high,resulting in difficult to spread like an oscilloscope.At the same time,the virtual logic analyzer based on PC is developed rapidly,its cost is relatively low,and it can meet the general requirements of digital signals detection.Therefore this paper studies the virtual logic analyzer based on FPGA controller,it has these charateristics: high sampling rate and memory depth,strong anti-interference ability,upgrading flexible,convenient carrying,low cost and other advantages.XC6SLX45 FPGA which is produced by Xilinx Inc,it provides excellent balance between low power consumption and high performance,and new functions can be realized by programming the chip.The FPGA connects a 2Gb SDRAM DDR3 chip through the memory controller block,and providing the cach for 16 channels.Each channel can ensure the storage depth of 1MB.The master controller and the host PC is connected by the USB cable,and the USB protocol processing is realized by the FX2 LP USB microcontroller from Cypress Inc.The human-machine interface is programmed by the graphical language LabVIEW,and the digital waveform is displayed through the virtual instrument interface.The Labview is an open source framework,its front panel and logic functions can be rebuilt by the user.After debugging between the hardware and software,it shows that there is no interference between channels,and the waveform can display by triggered stably and accurately.