Research Of Data Acquisition System For Micro-spectrometer Based On USB

The micro-spectrometer has many advantages compared with traditionalspectrometers. It can be used in many areas. The data acquisition system with moreprecision plays a role of great significance. The old data acquisition system usually beinstalled inside computer, there are some problems such as influencing system precisionbecause of disturbing in PC.Based on "Micro-spectrometer Analysis System"sponsored by National ScienceFoundation and "Micro biology and chemistry Analysis System"sponsored by National863 Foundation, on which be taken by Micro-System Center of Chongqing University, adata acquisition system for micro-spectrometer based on USB is developed, which willlay some technique foundation for micro-spectrum micromation and application.This paper focused on the following aspects::1. Based on the numerous researches works and analyzing for data acquisitionsystem of micro-spectrometer, put forward a design project about CCD driver circuit,data acquisition circuit and data transmission.2. Furthermore, the driver circuit based Complex Programmable LogicDevice(CPLD) has been demonstrated.3. ADuC812, a new type of microprocessor with fully integrated 12-bit A/Dconverter is adopted, it provides an ADC DMA mode, this allows the ADC results to bewritten directly to a external static memory SRAM without any interaction from theADuC812 core. This mode allows the ADuC812 to capture a contiguous sample streamat full ADC update rates(200kHz).4. To make data communication effectively and not expensive, some kinds ofexternal bus of PC were studied in the first instance, including PCI, RS-232 and so on.Finally, the Universal Serial Bus(USB) was adopted as the system's communication bus.USB has a preferable data transmission rate, support PC's plug-and-play architectureand bus-powered. In this part, three jobs will be finished, including developing driverprogram, firmware programming and USB interface circuit.5. A data acquisition system of micro-spectrometer is realized. Such experiment forthe data acquisition system has been executive with primarily satisfying result. It'sfeatures as follow:·High transmission over USB;·Sampling rate as high as 200KSps;·12-bitA/D conversion accuracy;·32K bytes on-board data memory;·The system is small, light and portable, and suitable for field use.