Based On Arm And Fpga High-speed Data Acquisition Card Design And Realization

Date acquisition is the premise of measure, the foundation of analysis and the beginning of cognition. Most precise device is based on the date acquisition. With the development of the electronic and digital technology, the speed of date transmission and the calculation of CPU are faster and faster; therefore the requirements of data acquisition and processing are more severe than before.It is hard for us to make a brilliant success in the area of high-end data acquisition due to the restraint of the technology of chip. At present the data acquisition card in our country are almost low-end products which are always used to deal with median frequencies low frequencies. And the systems of acquisition seldom are line with the demanding of our design. In this paper, high-speed data acquisition card is a part of high performance analytical instruments. The differences between this kind of cards and the others are that they are not rigid to the output of system and have the ability of data analyzing and processing. We successfully design a system of 250M sampling frequencies based on the structure of A/D, FPGA and ARM.This paper analyzes the system from Macro-and micro respect. From the macro point of view it analyzes data flowing, speed matching and the selection of specific means of communication of acquisition system and so on. We adapt ping-pong mechanism to reduce the speed of analyzing data and pre-difficult of FPGA which lead to the ease of processing Timing Margin of FPGA. DMA transfer is used as communication between ARM and FPGA which improve data transmission rates, and liberate the back-end ARM processor. From the micro point of view, data enter into the A/D converter from the front-end conditioning circuitry, FPGA collecting data on the output of A/D converter and go through the pre-operation of triggering and framing of data. After these operations, data are transmitted to the back-end of the ARM processor and then display on the LCD. A lot of difficult exited in the successful operation in the micro respect which is mainly about A/D data collection and the of transmission data. In the latter part of the system we encounter the dislocation data collection, the inefficiency of ARM and FPGA communication and the tension of timing in the pre-operation of FPGA. All of these issues have been settled by the revising of hardware and software.There are also some problems encountered in the design process of data acquisition card, such as the design of High-speed PCB, the reliability of hardware design reliability, redundancy and scalability of the system. All the solutions of these problems are illustrated in the last part of this paper.