Abstract:

In order to improve the accuracy of frequency measurement,an equal precision frequency meter based on EPM240 and MSP430 was designed.It includes constant temperature crystal oscillator,equal precision counting module, frequency calculation and display module.The CPLD（Complex Programmable Logic Device) chip EPM240T100C5 and MCU(Micro Controller Unit) chip MSP430F149 is the core of frequency meter,YM1602 is the display module.The theory calculation and conclusion of experiment shows that the range of frequency meter is 0.5 Hz～10 MHz;relative error is always below 2×10^-8;it meets the demand of frequency measurement in the project.

Key words: equal precision, frequency measurement, EPM240 chip, MSP430