Digital Storage Oscilloscope Based On ARM9-Research And Design On Data Acquisition System

Digital storage oscilloscope(DSO)is the modern development direction of the oscilloscope. It has great potential in market. At present common digital storage oscilloscope use DSP, embedded microprocessor based on FPGA or DSP + FPGA structure. Although the DSP powerful data-processing capacity, high speed, FPGA flexibility strong, and can fully develop and validate the design, easy to upgrade the systems. However, the general DSP and embedded microprocessor-based FPGA high price is not suitable for the development of low-cost embedded digital storage oscilloscope.The embedded digital storage oscilloscope is a low-cost, less function embedded smart terminal that can be used as a module. In reference to several digital storage oscilloscope hardware design, on the base of comparing and analyzing the advantages and disadvantages, we take a design that the hardware adopt ARM+FIFO structure, software adopt embedded real-time system uC/OS-II. ARM9 microprocessor uses the high-speed processing capacity, and advantages of FIFO control logic in reading and writing and high-speed data exchange to achieve 4-channel data synchronization. Use the transplant uC/OS-II system in ARM9 microprocessor to realize multi-task and real-time processing operation.The main research content include: system hardware design; uC/OS-II operating system migration and testing; multi-task design based on uC / OS-II; driver code design; launch code design; system testing.Demands of the functions and performance indicators include: analog input 0~+4V;4 synchronized through the importation and display; real-time voltage maximum 20 MSPS sampling and storage; sampling the smallest signal cycle 10us, pulse width 10us,the biggest signal cycle 15 ms; cycle, pulse width, voltage amplitude error (full range) is 0.5%; mouse graphical menu operation to replace the control panel; resolution 640×480 LCD display; 32 programmable input and output (16 input, 16 Output).This paper introduced all the major functional modules and the realization of the principle of ways in accordance with the input signal flows from hardware and software of systems. Analyze the front-end data acquisition system and related software and hardware design part, the driver and launch code design. Contrast the scheduled objectives of the hardware platform analyze and test the technical indicators.The development of ARM-based embedded technology of DSO has been completed and has passed the test. Test shows the embedded DSO achieve the requirements of function, except some problems of the analog input scope, the rest of the performance targets are achieved: analog-digital conversion maximum 20 MSPS; the error of cycle, pulse width, voltage amplitude (full range) in 0.5 percent; 4-channel input and can be simultaneously displayed; 32 programmable input and output stable and reliable; mouse graphics menu work good and simple convenience; LCD screen provides a good human machine interface.The system has high performance and good value. It can be used either as general digital storage oscilloscope or as an intelligent module in embedded systems.