Research on CPLD application in color measuring spectrophotometer

A method of spectral color analysis based on complex programmable logic device (CPLD) is proposed to improve the measurement accuracy of the colour measuring instruments and make the application rapid and convenient. The system control and color parameter calculation were accomplished, and the I/O control for the equipments was realized by utilizing CPLD and insetsingle chip to drive the CCD and to process the signal. By the aid of selfadaptive control theory, the problem that the CCD dynamic range was too narrow under the condition of single integration time was solved with the integration time adjustment for CCD by CPLD. The CCD effective data needed by calculation were reduced significantly through A/D intermittence sampling, data storage and invoking controlled by CPLD.