基于单片机的频率计摘要：数字频率计是一种基本的测量仪器。它被广泛应用于航天、电子、测控等领域，还被应用在计算机及各种数学仪表中。一般采用的是十进制数字，显示被测信号频率。基本功能是测量正弦信号，方波信号以及其他各种单位时间内变坏的物理量。由于其使用十进制数显示，测量迅速精确，显示直观，所以经常被用来使用。本文主要介绍数字频率计的设计和调试，本作品是基于 STC89C52 单片机作为平台，基本原理是通过 STC89C52 单片机进行频率的采集和分析工作，在通过程序使其显示在 LCD1602 的液晶显示屏上，通过液晶显示屏，让使用者能够直观的看到当前的输入频率是多少。由于 STC89C52 单片机只能处理数字信号因此系统需要先把信号放大成方波信号，再通过施密特触发器整形方波，又由于单片机能处理的频率有限，所以这次我们先用 74HC390 芯片对输入的信号进行了分频，使其降低了 100 倍，才送去给单片机处理，如果频率高于 200KHZ 的时候就计算分频后的频率，得到数据再换算成真实的频率。关键词：单片机， LCD 显示屏，分频器。 IAbstractDigital frequency meter is a basic measuring instrument. It is widely used in aerospace, electronics, measurement and control and other fields, but also used in the computer and various mathematical instruments. Generally, decimal Numbers are used to display the measured signal frequency. The basic function is to measure the sinusoidal signal, square wave signal and other various units of time bad physical quantity. Because it USES decimal number display, measurement is rapid and accurate, display intuitive, so often used.This paper mainly introduces the design and debugging of digital frequency meter, this work is based on STC89C52 single-chip computer as the platform, the basic principle is through the STC89C52 single-chip microcomputer frequency acquisition and analysis, through the program to make it displayed in the LCD1602 LCD screen, through the LCD screen, let users can directly see what is the current input frequency.Because STC89C5...
