说明：   该文档是我大学的毕业设计，一个频率计的设计实例，原创，里面还有实物的图片！其中用到单片机和FPGA相结合的方案！
(The document that I graduated from the University of Design, a design example of frequency, originality, there is also kind of picture! Which used a combination of MCU and FPGA program!)