单片机PWM调光

Dear 丶 2022-10-01 06:45 157阅读 0赞

**项目描述：**  
由三个按键分别控制LED的开关、变亮、变暗。灯的亮度调节采用单片机产生的PWM实现。  
**C语言代码如下：**

/*-----------------------------
    FileName:PWMDimming.h
    Function: 头文件
    Author: Zhang Kaizhou
    Date: 2019-6-11 16:49:42
    ------------------------------*/
    #include <reg52.h>
    #include <string.h>
    #define uchar unsigned char
    #define uint unsigned int
    #define PERIOD 100 // PWM信号周期为 100ms
    
    /*主模块端口定义*/
    sbit led = P1^7;
    sbit onOff = P3^4;
    sbit addLight = P3^5;
    sbit decLight = P3^6;
    
    /*LCD1602显示模块端口定义*/
    sbit lcdrs = P1^0;
    sbit lcdrw = P1^1;
    sbit lcden = P2^5;
    
    /*主模块函数声明*/
    void delay(uint xms);
    void keyScan();
    void dimming();
    void generatePWM();
    
    /*LCD1602显示模块函数声明*/
    void LCDInit();
    void display(uchar dat);
    void writeCommand(uchar command);
    void writeData(uchar dat);

/*-------------------------------------------------
    Function: 单片机PWM调光
    Description: 按键控制LED灯开关，四个亮度等级的调光;
    LCD1602实时显示LED灯的亮度等级。
    Author: Zhang Kaizhou
    Date: 2019-6-11 15:37:10
    --------------------------------------------------*/
    #include "PWMDimming.h"
    
    /*全局变量定义*/
    uchar brightness = 0; // 亮度标志
    uint count = 0;
    bit onFlag = 0; // 0-关灯 1-开灯
    
    void main(){
    	LCDInit();
    	led = 1; // 上电时灯处于关闭状态
    	while(1){
    		keyScan();
    		display(brightness);
    		dimming();
    		generatePWM();
    	}
    }
    
    /*键盘扫描函数*/
    void keyScan(){
    	if(!onOff){ // 开关灯
    		delay(5);
    		if(!onOff){
    			while(!onOff);
    			led = onFlag;
    			onFlag = ~onFlag;
    			if(onFlag){
    				brightness = 1; // 开灯初始亮度为1
    			}else{
    				brightness = 0;
    				led = 1;
    			}
    		}
    	}else if(onFlag){ // 灯处于开的状态
    		if(!addLight){ // 变亮
    			delay(5);
    			if(!addLight){
    				if(brightness < 4){
    					while(!addLight);
    					brightness++;
    				}
    			}
    		}
    		if(!decLight){ // 变暗
    			delay(5);
    			if(!decLight){
    				if(brightness > 1){
    					while(!decLight);
    					brightness--;
    				}
    			}
    		}
    	}
    }
    
    /*调光程序*/
    void dimming(){
    	switch(brightness){
    		case 1: count = 80; break; // 80%占空比
    		case 2: count = 90; break; // 90%占空比
    		case 3: count = 95; break; // 95%占空比
    		case 4: count = 100; break; // 100%占空比
    		default: break;
    	}
    }
    
    /*产生PWM信号*/
    void generatePWM(){
    	if(onFlag){ //亮灯时产生PWM信号
    		led = 0;
    		delay(count);
    		led = 1;
    		delay(PERIOD - count);
    	}
    }
    
    /*延时函数*/
    void delay(uint xms){
    	uint i, j;
    	for(i = xms; i > 0; i--)
    		for(j = 110; j > 0; j--);
    }

/*-----------------------------
    FileName:display.c
    Function: LCD1602显示函数
    Author: Zhang Kaizhou
    Date: 2019-6-11 16:49:02
    ------------------------------*/
    #include "PWMDimming.h"
    /*显示信息数组*/
    uchar code table0[] = {"PWMDmimming"};
    uchar code table1[] = {"Brightness:"};
    uchar code table2[] = {"01234"};
    uchar num = 0;
    
    /*初始化LCD1602的设置*/
    void LCDInit(){
    	uchar i;
    	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*/
    	writeCommand(0x80); // 将数据指针定位到第一行首
    	for(i = 0; i < strlen(table0); i++){
    		writeData(table0[i]);
    		delay(5);
    	}
    	
    	writeCommand(0x80 + 0x40); // 将数据指针定位到第二行首
    	for(i = 0; i < strlen(table1); i++){
    		writeData(table1[i]);
    		delay(5);
    	}
    }
    
    /*LCD显示函数*/
    void display(uchar dat){
    	writeCommand(0x80 + 0x40 + strlen(table1));
    	writeData(table2[dat]);
    	delay(5);
    }
    
    /*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;
    }

**扩展：**  
1.可根据需求增加或减少LED灯的亮度等级；  
2.可通过改变个亮度等级对应的PWM的占空比来改变个亮度等级对应的灯的亮度；  
3.因为此处PWM调制主要是根据占空比的不同控制LED的亮度，因此用软件延时即可。