Design Of Data-Acquisition System For Micro Fiber Optic Spectrometer Based On Stm32

The spectrometer is a kind of precision optics analysis instrument which is used to analyze various kinds of substances chemical components and its content. It is applied extensively in many fields such as physical experiments, chemic analysis, biological research, medical science and medicine study, industrial and agricultural production, national defense, etc. It is important for spectrometers to be miniaturized and microminiaturized, as well as to analyze in real-time and in siturapidly. As an important part of spectrometer, data-acquisition and transmission system is one of the key to realize the above request. In this thesis, based on understanding the optical system and circuitry system the most popular micro fiber spectrometer, a new data-acquisition systenm for micro-spectrometer is designed based on STM32. It acts in concert with the optical system to constitute a micro fiber spectrometer. Its working wavelength is300-900nm, element resolution1.5nm. The new data-acquisition system is developed to realize the miniaturization and micromation of the spectrometer, and content the requirements of real-time measurement with high speed.According to the requirement of design requirements, we build optical system platform, using blaze grating, two spherical mirror, and a small dispersing system based on crossing Czerny-Turner structure. According to the requirement of spectral measurement, the entire spectrum is detected by a CCD for one times. The CCD is the product of Toshiba Corporation, linear charge coupled device TCD1304DG, and then received light signal is converted to an electrical signal. After high-speed A/D converter sampling circuit, sampling results temporarily stored in the RAM. The microcontroller sends the data to PC for processing, analysis and graphics display based on USB. It resolves conflicts between a large number of CCD output data and the microcontrollers speeding in handling large amounts of data. To ensure the accuracy of the entire system timing and the flexibility of control, many function modules can be generated by the logic cells inside of the CPLD chip, such as CCD driving timing, the driving timing of high-speed A/D sampling, storage system and data transmission timing. With the helping of the environment of QuartusⅡ, the CPLD is programmed in VHDL and compiled, synthesized, simulated and burned. We select STM32F103x8series chip as the microprocessor, with USB and fully compatible with USB2.0full speed transport protocol. Because of using USB interface, the speed of spectrometer system is increased, and the hardware system of the spectrometer is small in volume, light in weight, compact and portable in configuration, and suitable for field, with the performance of bus-powered mode, plug and play.