Based On Usb2.0 Multi-channel High-precision Data Acquisition System Developed

This paper is mainly concerned with the design of a high precision and multi-channel data acquisition system based on USB2.0 interface and Large Scale FPGA. The design scheme, developing method and developing process of a suit of data acquisition system used high precesion ADC converter ADS8322 and Xilinx's Spartanâ…¡XC2S200E-P0208 and Cypress's EZ-USB FX2 are expatiated.USB is a type of computer bus which increasingly prevails in recent years. With USB having many advantage, the research of application about USB in many fields is developing. In the field of data acquisition, data acquisition devices based on USB not only have the advantage of speed on data acquisition, being conveniently expanded, but also are able to be applied to more broad fields with plug-and-play function.There are 5 sections total. The paper firstly discusses problems that real-time data acquisition systems are facing and excellent advantages of USB. The system scheme is introduced briefly. The main work and the main content are also introduced in brief. In chapter 2, the paper presents key features and specifications of this system. The circuit is designed based on the requirement of the system. The A/D and USB interface chips are selected and explained summarily. The paper also briefly introduces how to choose large scale FPGA, and consequently choose a FPGA EVM as development platform. The system design consists of hardware design and software design. In chapter 3, the paper presents hardware design of the system. The hardware design includes analog to digital converter circuit design, control circuit design and USB interface circuit design. In the ADC circuit design, the paper introduces signal conditioning circuit and 1/8 multiplexer. The signal is filtered, amplified and digitized in the signal conditioning circuit. The paper presents the design in detail, and analyzes the performance by EDA tool. In addition, it discusses EMC problem in circuit design. In the control circuit, the paper introduces FPGA design in detail. Finally the circuit schematic diagram of USB interface is presented. In chapter 4, it introduces the software design in detail. Software of this system consists of 3 parts: firmware, driver and application software. At first the paper introduces firmware design and part of source code in detail. In application software design, the paper presents design methods of application software, which is based on Matlab Simulink S-function. This system takes Matlab Simulink based S-function as its application software and user interface under Windows 2000. This is an innovative work of mine. In the data acquisition testing, An simulink test module is presented. The system acquired sine wave signal from a signal generator, and performed the FFT calculation to certify that this system can work fine.