基于USB接口的逻辑分析仪硬件设计

【作者】 余远昱；

【导师】 王厚军；

【作者基本信息】 电子科技大学 ， 测试计量技术及仪器， 2005， 硕士

【摘要】 逻辑分析仪是最重要的数据域测试仪器之一。随着数字化进程的加快,逻辑分析仪应用越来越广泛,在其功能、性能提高的同时,对其携带和操作的方便性也提出了新的要求。基于USB 接口的便携式逻辑分析仪,结构轻巧,携带方便,并利用计算机的强大计算能力提高了仪器的数据处理和显示能力,在性能提高的同时降低了仪器成本。本文主要阐述了基于USB 接口的逻辑分析仪的硬件设计原理并提出了设计方案。根据硬件设计工作的重点和难点,文章着重阐述了逻辑分析仪数据捕获部分和USB 接口部分的硬件工作原理与设计方案,文中也对与硬件密切相关的软件部分做了简要介绍。本文第一章介绍了逻辑分析仪在数据域测试领域的应用情况及发展趋势,同时给出了课题的任务和指标。第二章则结合设计指标,分析了系统的硬件设计结构和供电方式,提出了设计工作的重点:数据捕获部分和USB 接口部分的设计。第三章详细阐述了数据捕获部分中各功能电路的设计原理与方案,重点讨论了触发识别电路和存储控制电路的设计,并提出了一种增加存储容量的方案。第四章在介绍USB 的基本特性后提出了USB 接口设计方案,其中详细介绍了USB 接口芯片与数据捕获电路部分的信号线连接关系。第五章简要介绍了USB 接口芯片的固件设计原理,详细阐述了批量传输的实现方法。第六章简要介绍了数据采集程序的设计方案与工作流程。第七章介绍了整机的测试方案并针对USB 接口的数据传输速率进行性能分析。第八章为对硬件设计工作的总结。经测试表明,该逻辑分析仪具备了较强的逻辑分析能力,并有良好的USB 接口数据传送能力,能满足高速信号分析的要求。更多还原

【Abstract】 Logic analyzer is one of the most important data domain test instruments. Withthe accelerating advancement of the digitization process, logical analyzer is gettingwidely used. As its functions and capabilities raised, there are new demands foroperational convenience and easy portability. Portable logic analyzer based on USB islight and handy, which is easy to carry and operate. With utilization of computer, thelogic analyzer based on USB enhances data transmission, process, display and storage,which improves the performance of data analyzing, and in another aspect, it can alsogreatly lower the cost of the instrument.This paper expatiates the principle of the hardware design of a logic analyzerbased on USB and brings forward a scheme. The principle and design of the dataacquisition section and the USB interface section are emphasized in this paperaccording to the difficulties of the hardware design. The software, which is closelyrelated with the hardware, is also mentioned in the paper.The first chapter describes the logic analyzer’s application and developmenttends in the field of data domain test. The work and the specified specs of thisinstrument are also introduced in this chapter. Chapter 2 specifies the scheme andpower supply mode of the logic analyzer based on USB according to the design target,also mentions that the data acquisition circuit and the USB interface circuit are thecritical parts of the design.The principle and design of the circuits in data acquisition section are expatiatedin chapter 3, which introduces the designs of the trigger word distinguished circuitand the storing control circuit in detail. A design of increasing storing capability isalso introduced in this chapter. Chapter 4 describes the USB protocol and a design ofUSB interface circuit. The signals connection between the data acquisition section andthe FX2 is described in this chapter.The firmware for the EZ-USB FX2 and the realization of USB bulk transfer areexpatiated in chapter 5. The design and flow chart of the data acquisition program aredissertated in chapter 6. Chapter 7 introduces a test methodology for this logicanalyzer and discusses the data transfer speed of the USB interface. The hardwaredesign of this logic analyzer is summarized in chapter 8.Testing shows that the logic analyzer is provided with powerful data analyzingability, as well as rapid data transfer speed of USB interface, which ensure theinstrument to be competent for analyzing high speed signals.更多还原