单片机测量信号频率

比眉伴天荒 2022-01-21 20:13 293阅读 0赞

**仿真原理图如下：**  
MCU和LCD1602显示模块：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODY3OTkyNA_size_16_color_FFFFFF_t_70]  
启动及清零信号控制模块：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zODY3OTkyNA_size_16_color_FFFFFF_t_70 1]

**C语言代码如下：**

/*----------------------------------------
    FileName: main.c
    Function：测量0 ~ 9999Hz之间的数字信号的频率
    Author: Zhang Kaizhou
    Date: 2019-6-5 22:39:16
    ---------------------------------------*/
    #include "FrequencyMeasure.h"
    
    bit flag = 0;
    uint freq = 0, count = 0, time = 10; // 定时器Timer0溢出次数
    
    void main()
    {
    	LCDInit();
    	displayInit();
    	freqMeasure();
    	display(freq);
    	while(1);
    }
    
    void freqMeasure()
    {
    	Dclr = 0; // 产生D触发器的清零正脉冲
    	delay(5);
    	Dclr = 1;
    	
    	TMOD = 0x59; // Timer1 非门控 方式一 计数器;Timer0 门控 方式一定时器
    	TH0 = (65536 - 50000) / 256; // Timer0 定时50ms 赋初值
    	TL0 = (65536 - 50000) % 256;
    	TH1 = 0x00; // Timer1 计数 赋初值0
    	TL1 = 0x00;
    	TR0 = 1; // 启动Timer0
    	TR1 = 1; // 启动Counter1
    	ET0 = 1; // 开外部中断0
    	EA = 1; // 开全局中断
    	
    	startSignal = 0; // 产生测量正脉冲信号 启动测量
    	delay(5);
    	startSignal = 1;
    	while(!flag); // 测量中
    	
    	Dclr = 0; // 产生D触发器清零正脉冲 终止测量
    	delay(5);
    	Dclr = 1;
    	TR0 = 0;
    	TR1 = 0;
    	count = TH1 * 256 + TL1;
    	freq = count * 2; // freq = count / time(s)
    }
    
    void timer0() interrupt 1
    {
    	TH0 = (65536 - 50000) / 256;
    	TL0 = (65536 - 50000) % 256;
    	time--;
    	if(!time)
    	{
    		flag = 1;
    	}
    }

/*-----------------------------
    FileName:display.c
    Function: LCD1602显示函数
    Author: Zhang Kaizhou
    Date: 2019-6-5 22:43:18
    ------------------------------*/
    #include "FrequencyMeasure.h"
    
    uchar code table0[] = {"Period Measure"}; // 每行的字符数据
    uchar code table1[] = {"Period:0000"};
    uchar code table2[] = {"0123456789"};
    uchar num, ge = 0, shi = 0, bai = 0, qian = 0;
    
    /*初始化LCD1602的设置*/
    void LCDInit()
    {
    	lcden = 0; // 拉低使能端，准备产生使能高脉冲信号
    	writeCommand(0x38); // 显示模式设置(16x2， 5x7点阵，8位数据接口)
    	writeCommand(0x0c); // 开显示，不显示光标
    	writeCommand(0x06); // 写一个字符后地址指针自动加1
    	writeCommand(0x01); // 显示清零，数据指针清零
    }
    
    /*LCD上电界面*/
    void displayInit()
    {
    	writeCommand(0x80); // 将数据指针定位到第一行首
    	for(num = 0; num < strlen(table0); num++)
    	{
    		writeData(table0[num]);
    		delay(5);
    	}
    	
    	writeCommand(0x80 + 0x40); // 将数据指针定位到第二行首
    	for(num = 0; num < strlen(table1); num++)
    	{
    		writeData(table1[num]);
    		delay(5);
    	}
    }
    
    /*LCD显示函数*/
    void display(uint freq)
    {
    	if(freq < 10) // 10us以下
    	{
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x01);
    		writeData(table2[freq]);
    	}else if(freq < 100 && freq >= 10){ // 10us ~99us
    		shi = freq / 10;
    		ge = freq % 10;
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x02);
    		writeData(table2[shi]);
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x01);
    		writeData(table2[ge]);
    	}else if(freq < 1000 && freq >= 100){ // 100us ~ 999us
    		bai = freq / 100;
    		shi = freq % 100 / 10;
    		ge = freq % 10;
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x03);
    		writeData(table2[bai]);
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x02);
    		writeData(table2[shi]);
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x01);
    		writeData(table2[ge]);
    	}else if(freq < 10000 && freq >= 1000){ // 100us ~ 999us
    		qian = freq / 1000;
    		bai = freq % 1000 / 100;
    		shi = freq % 100 / 10;
    		ge = freq % 10;
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x04);
    		writeData(table2[qian]);
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x03);
    		writeData(table2[bai]);
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x02);
    		writeData(table2[shi]);
    		writeCommand(0x80 + 0x40 + strlen(table1) - 0x01);
    		writeData(table2[ge]);
    	}
    }
    
    /*写指令函数*/
    void writeCommand(uchar command)
    {
    	lcdrs = 0; // 命令选择
    	lcdrw = 0;
    	P0 = command;
    	delay(5);
    	
    	lcden = 1; // 产生一个正脉冲使能信号
    	delay(5);
    	lcden = 0;
    }
    
    /*写数据函数*/
    void writeData(uchar dat)
    {
    	lcdrs = 1; // 数据选择
    	lcdrw = 0;
    	P0 = dat;
    	delay(5);
    	
    	lcden = 1;
    	delay(5);
    	lcden = 0;
    }
    
    /*延时函数*/
    void delay(uchar xms)
    {
    	uint i, j;
    	for(i = xms; i > 0; i--)
    		for(j = 110; j > 0; j--);
    }

/*----------------------------
    FileName: FrequencyMeasure.h
    Function: 头文件
    Author: Zhang Kaizhou
    Date: 2019-6-5 22:45:16
    -----------------------------*/
    #include <reg52.h>
    #include <string.h>
    #define uchar unsigned char
    #define uint unsigned int
    
    sbit lcdrs = P1^2; // LCD数据/命令选择端
    sbit lcdrw = P1^3; // LCD读写选择端
    sbit lcden = P1^4; // LCD使能端，高脉冲有效
    sbit Dclr = P1^5; // D触发器清零端
    sbit startSignal = P1^6; // 启动信号频率测量启动信号
    
    void startMeasure();
    void display(uint period);
    void LCDInit();
    void displayInit();
    void writeCommand(uchar command);
    void delay(uchar xms);
    void writeData(uchar dat);
    void freqMeasure();

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