Development Of Scanning AD Module Based On CPCI

As an important instrument for testing and measuring equipment,data acquisition card has been widely used in aerospace,industrial control and other fields.IC chips used for data acquisition products in the current domestic market have long relied on foreign suppliers and are mostly restricted by American companies.With the trade dispute between China and the United States,the risk of embargo on key chips is getting higher and higher.Therefore,it is increasingly important to develop a data acquisition card based on domestic chips.Therefore,the development of a data acquisition card based on domestic chips has become more and more important.This paper aims to develop a domestic scanning A/D module based on CPCI bus.The module has 32 differential channels,the sampling resolution is 16 bits,and the maximum sampling rate of single channel is 100 k Hz.The main research contents of this paper include the following sections.1.The hardware circuit implementation scheme of 100 % domestic IC chip is proposed.Determined to use the SDA7656 AD conversion chip as the data acquisition core,the ‘DSP + FPGA' method as the hardware main control processing core,DDR2 as the data memory,and the CPCI bus as the communication method with the host computer.Hardware circuit design of scanning AD module is realized.2.Proposed FPGA logic implementation scheme based on IP core technology.The whole logic includes sampling control logic,CPCI bus interface logic and DDR2 interface logic.Sampling control logic realizes channel selection,sampling rate control,range adjustment and AD chip control.CPCI bus interface logic designs CPCI bus controller on the basis of PCI IP core.The controller mainly includes the initialization of PCI IP core control signal and the reading and writing of IP core internal data.DDR2 interface logic also uses IP core to control DDR2 memory.3.Module software program is designed.Software design includes DSP software program and upper computer instrument driver conforming to VPP standard.The DSP program mainly controls each hardware module according to the host computer command.Instrument driver is mainly based on the index requirements and users' requirements to complete the corresponding functions,including the configuration of sampling,sampling data reading,storage and other functions.After completing the design of the hardware circuit,FPGA logic and software program of the module,a module test platform is built to test the functions and performance indexes of the module.The test results show that the module fully meets the requirements of precision,sampling rate,storage depth and other key technical indicators.At the same time,the scanning AD module fully realizes 100 %localization of integrated circuit chips.