The Research For Data Acquisition System Based On USB 2.0 And FPGA

During the science and technologies development in today's world, to make the measurement more precise in the research and production, there are higher and higher demands for the performance of measurement systems. Traditional measurement systems and devices have the fault of low transmission rate and are not easy for installation. And from current view, these systems and devices cannot fulfill the higher demands in the industrial world. USB technology can solve the problems above. USB bus has been widely used for the features of:"plug-in and play", easy for extensions and high transmission rate (480Mbps in the protocol of USB 2.0).This paper describes a Data Acquisition System (DAQ) based on USB 2.0.After the introduction of the USB protocol, this paper describes the system architecture, hardware, software and system performance, from which, the design and solution is given. The system has dual analog channels with 2 channels 12-bits AD converters; the highest sample rate is 200 KHz. The interface chip is CY7C68013 of Cypress. As well, this paper introduces the circuit design and program design for the mode of Slave FIFO of this chip. The system takes a FPGA chip as core logic control module. FPGA controls the sample process and communications with the USB chipset. FPGA also generates the control signals and timing sequence signals. This design will improve the system stability, and makes the device smaller. This paper also gives an overview of software part in the system, includes logical design in FPGA, timing control, firmware of 8051, driver and the client application at PC. At client PC side, Microsoft Visual Studio C++ 6.0 is chosen as the platform for development.To verify the reliability and accuracy of DAQ system, experiments were executed against the standard signals and bakelite thermal conductivity. At last of this paper, the experiment result is given and analyzed.