六位数码管频率计。工作原理： * 1S 钟内对输入脉冲所计数的次数则为频率值。-Six digital frequency meter tube. Working Principle:* 1S minutes by counting the input pulse frequency, compared with the value of the number.

频率计数测量方法，有利于基于单片机开发的人学习-Frequency count measurement method, the development is conducive to learning from the people based on single chip