外文翻譯---基于arm與線性ccd的高速數(shù)據(jù)采集系統(tǒng)-其他專業(yè)(編輯修改稿)
2025-02-24 09:27 本頁面
【文章內(nèi)容簡介】 d conversion device is adopted. It’s a singlechannel, 8bit A/D converter, which operates over a wide range of temperature, converts fast, operates at conversion rates up to 230 MSPS, thus achieving entire signal acquisition of linear array CCD. ADC08200 is shown in figure 3. 河北大學 工商學院 2021 屆 本科生畢業(yè)外文翻譯 4 Fig 3 Highspeed A/D converter ADC080200 FIFO is used as a data buffer to coordinate the rate of ARM processor and ADC. It is a twoport (input and output port) memory for temporary storage of first in first out data. Due to the time to write data to FIFO is far less than the A/D conversion time, therefore, the acquisition speed depends on the A/D conversion speed. In order to improve the speed of the entire measurement system, the time sequence of entire circuit is precisely controlled by the CPLD to make the circuit works harmonious. CCD driving signal, integration time control, address decoding, A/D conversion control, data buffer and data acquisition logic functions integrate in the CPLD, so that the entire circuit structure is simple and reliable. In order to further enhance the system speed, when the system starts, system programs are transferred to highspeed SRAM for running and SDRAM for data storage。 SRAM, SDRAM should be placed as close as possible to ARM processors, and the signal lines the shortest possible. ARM processor (AT91RM9200), the signal processing core of the entire hardware system, read the CCD light intensity signal from FIFO, calculate the distribution of contactline image in the CCD with corresponding algorithm, and transfer the result to the slave puter through USB. C. Transmission speed between ARM processor and puter In order to increase the speed of data transmission and reduce transmission delay, USB interface is used for data transmission. interface support lowspeed and fullspeed transmission, data transfer rates has reached in lowspeed mode, the transmission speed up to 12Mbps in full speed mode. Philips Company’s PDIUSBD12 is adopted. When a USB device inserted into the PC, PC enumerates USB device automatically. When detecting equipment to insert, PC send query request. USB devices respond to the request and send equipment Vendor ID and Product ID。 PC loads the corresponding device driver with these two ID to plete the enumeration process. PCside USB device driver is pleted by WinDriver. Data munication between PC and USB equipment mainly includes two aspects: first, read the sample data。 second, send control mands to the acquisition system. IV. CCD image recognition algorithm 河北大學 工商學院 2021 屆 本科生畢業(yè)外文翻譯 5 ARM processor is mainly respo
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