Design Of Acquisition And Control Module Of Near-Infrared Spectrometer Based On Embedded Systems

Near-infrared spectroscopy technology in recent years has been the repid developing high-tech analysis in the field of analytical chemistry. Increasingly used in agriculture, geology, oil and other analysis. Near-infrared analytical instruments are also developed in the direction of Specialization,Smaller,solid-state-based,modular and rapid real-time,with the development of near-infrared technologyEmbedded system widely used computer platform in the post-PC era, has been widely used in many mature fields, such as industrial controls, communications equipment, medical equipment, military equipment and so on, due to its small size, performance, low power consumption. And now Embedded systems has become a bright spot in the field of computer and changed the people's production and lives in a variety of forms quietly .Near-infrared spectrometer based on embedded is a new analytical instrument,developed for near-infrared analysis technology,based on the use of the embedded processor ARM-S3C2410's external interface, and processing ability, and excellent stability characteristics of the system.In wy laboratory ,we have developed a PC-based single-chip the raster scan-based near-infrared spectrometer and CCD-based near-infrared spectrometer,and initially completed the embedded raster scan-based monitoring and control circuit design, including the stepper motor module, USB interface circuit, keyboard, power supply modules, serial interface circuit and JTAG circuit design . However, in the function and system performance there are a lot of shortcomings and insignificance:(1) There will always be abnormal in the most important A / D data acquisition module, not be able to collect real-time data to the right;(2) System comes with a smaller capacity FLASH and not able to meet the high-capacity access and data storage of fixed calibration samples(3) The original measurement and control system can not read data from the internal FLASH when power off, Cramfs used by the file system is read-only file system ,that can not directly store the data in FLASH after data acquisition;(4) Human-Computer Interaction isn't friendly enough. Embedded systems should play its powerful features in order to make the portable near-infrared spectrometer operated more easilyFor the shortage of Monitoring and control module as above, this Design completed the further improvement of acquisition and storage modules of the equipment. Specific completed work is as follows:(1) Developed new hardware interface circuit(sSD / MMC card interface,NANDFLASH interface,TSP (Touch Screen) interface), modified the error of original A / D acquisition circuit.using the Embest IDE tool which is Applicable to Embedded hardware development , maked rapid online simulation debugging for every interface circuit. And is preparing for the next step development of the Linux device driver , based on proving the design of the interface circuits right.(2) Put up Embedded cross compiler environment for Linux device driver development; transplant Startup code VIVI, Core kernel,File System Cramfs,Build embedded Linux systems which Equipment required.After the building of Embedded development system, for the requirements of different hardware interfaces, develop the corresponding device driver.(3) Performance test for each device Interface,to ensure that SD / MMC can mount, read, storage and other functions, and can also read the contents of memory card from PC through the card reader circuit; TSP (touch screen) to read coordinates,the conversion function; A / D conversion circuit to sample real-time, correct near-infrared spectral data.We have to compare laboratory test results with the original equipment to verify the correctness of data collection.