The Design Of Digitizer System Based On DSP

With the rapid development of digital technology, DSP is widely applicable in data processing due to its powerful capability of digital operation of the signal in theory and methods. The conventional navigation plotter system can not capture the data of coordinates on paper charts, and have the problems of big error and low precision. In order to solve the problems above, digital technologies have been applied successfully in navigation plotter system. The study takes certain type of navigation plotter dais of my school as background, and designs a real-time digitizer system based on DSP.First, the background of research and the development state of digitizer at home and abroad are introduced, and the technology of digital signal processor is discussed briefly in the paper. After that, the composition and principle of digitizer system and the relationship between digitizer system and navigation plotter system are introduced. Then, the design principle of Electromagnetism digitizer board, which is an important part of the digitizer system, is discussed significantly,and the common magnetic field is given.After analyzing the whole function requirements of system, the general scheme of the system's hardware is given. In the design of the hardware platform, the TMS320VC5409 DSP of TMS320C54x series of TI Corporation are taken as core processor chip to design digitizer system. The asynchronous serial port ST16C550 chip, A/D conversion chip MAX121, SDRAM and FLASH are taken as chief peripherals to complete the minimum system design of DSP. The specific hardware circuit include:power module, Reset module, Clock module, JTAG interface module, Memory interface module, exterior interface circuit module and so on.The design of software is completed in the later chapters. The main flow chart of the system is given and explained firstly. Then the system initialization process, Boot loader loading procedure, Non-volatile FLASH on-line programming, Serial communication program and Data processing program design are designed detailedly. The algorithm of picking data of coordinates in the data processing is studied in certain extent, and the error analyse of two function arithmetic is completed. Finally, software and hardware are debugged and the whole system performance is tested, meanwhile, the test results are analyzed. The results show that, the digitizer system can pick up the coordinate data in real time in paper charts and the accuracy is improved to some extent, as a result, the performance of the whole system is improved. Finally, the work done in this topic is summarized, and the places of deficient and to be perfected are given in the design.