51单片机实现数字时钟

     用单片机实现数字时钟,关于时间显示,是用的1602液晶,C51单片机,然后再加一个定时器,每到一秒就动态的更新一下液晶的时间显示,在更新的时候也要计算相应的分针和时针的变化,还要注意边界问题.为了能够达到一个最好的效果,我还加了一个键盘扫描,用到了3个键,分别为功能键,增1,减1来实现用户自定义时间.
     在实现过程中,用到了单片机的中断系统的相关知识,还有定时器,液晶显示,键盘的动态扫描,都是以前的知识,没什么难度.
    程序如下,可以正常运行.

#include <reg52.h>
#define uint unsigned int
#define uchar unsigned char

sbit lcdrs = P1^0;
sbit lcdrw = P1^1;
sbit lcden = P1^2;

sbit key0 = P2^0;//功能键,选择时分秒
sbit key1 = P2^1;//加1键
sbit key2 = P2^2;//减1键
sbit key4 = P2^4;

uchar key0_count;//按键0被按的次数(0~3)

char hour,minute,second; //时分秒
uint timer_count;  //定时器中断计数

uchar table_date[] = "2009-4-12  Mon";
uchar table_time[] = "00:00:00";

/****** 函数申明 ********/
void write_cmd_1602(uchar cmd);
void write_data_1602(uchar dat);
void write_add(uchar add,uchar dat);
void init1602();
void delay(uint z);
uchar reverse(uchar c);
void keyscan();
void init();
/****** 主函数 ********/
void main()
{
	init();
	//init1602();
	//while(1);
	while(1)
	{
		keyscan();
		delay(5);
	}
}
//1602液晶初始化
void init1602()
{
	lcdrw = 0;  		   //本程序只读不写,故将其置低
	lcden = 0;			   //关闭1602
	delay(5);
	write_cmd_1602(0x01);  //清屏
	write_cmd_1602(0x38);  //显示模式
	write_cmd_1602(0x0c);  //开显示,不显示光标,不闪烁
	write_cmd_1602(0x06);  //地址指针自动加1
	write_cmd_1602(0x80+1);//将光标指向第一行第二个位置
	delay(5);
}
void delay(uint z)
{
	uint x,y;
	for(x=z;x>0;x--)
		for(y=110;y>0;y--);
}
/** 将发送的数据进行翻转,高位到低位,低位转到高位 **/   
uchar reverse(uchar c)   
{   
   uchar chbuff=0;   
   if (c&0x01) chbuff=chbuff|0x80;   
   if (c&0x02) chbuff=chbuff|0x40;   
   if (c&0x04) chbuff=chbuff|0x20;   
   if (c&0x08) chbuff=chbuff|0x10;   
   if (c&0x10) chbuff=chbuff|0x08;   
   if (c&0x20) chbuff=chbuff|0x04;   
   if (c&0x40) chbuff=chbuff|0x02;   
   if (c&0x80) chbuff=chbuff|0x01;   
   return chbuff;   
}
//向液晶写命令
void write_cmd_1602(uchar cmd)
{
	lcdrs = 0; //低表示写命令,高表示写数据
	delay(5);
	P0 = reverse(cmd);
	delay(5);
	lcden = 1; //给一个高脉冲
	delay(5);	
	lcden = 0;
	delay(5);
}
//向液晶写数据
void write_data_1602(uchar dat)
{
	lcdrs = 1; //低表示写命令,高表示写数据
	delay(5);
	P0 = reverse(dat);
	delay(5);
	lcden = 1; //给一个高脉冲
	delay(5);	
	lcden = 0;
	delay(5);
} 
//根据地址向液晶写数据
void write_add(uchar add,uchar dat)
{
	uchar shi,ge;
	shi = dat/10;
	ge = dat%10;
	delay(5);
	write_cmd_1602(0x80+add);
	write_data_1602(shi+0x30);
	delay(5);
	write_data_1602(ge+0x30);
}
//键盘扫描函数
void keyscan()
{
 	key4 = 0;
	if(0==key0) //第一个键被按下
	{
	 	delay(5); //消抖
		if(0==key0)
		{
			key0_count ++;
			if(4==key0_count)
				key0_count = 0;
			while(!key0); //松手检测
			if(0==key0_count)
			{
				TR0 = 1;  //重新开始计时
				write_cmd_1602(0x0c);  //禁止显示光标并不让其闪烁	
			}
			if(1==key0_count)
			{
				TR0 = 0;  //暂停计时
				write_cmd_1602(0x80+0x40+11);//将地址指针指向秒的位置
				write_cmd_1602(0x0f);  //显示光标并闪烁
				delay(5);	
			}
			if(2==key0_count)
			{
				TR0 = 0;  //暂停计时
				write_cmd_1602(0x80+0x40+8);//将地址指针指向分的位置
				write_cmd_1602(0x0f);  //显示光标并闪烁
				delay(5);
			}
			if(3==key0_count)
			{
				TR0 = 0;  //暂停计时
				write_cmd_1602(0x80+0x40+5);//将地址指针指向小时的位置
				write_cmd_1602(0x0f);  //显示光标并闪烁	
				delay(5);
			}
		}
	}
	if(0==key1) //第二个键被按下
	{
	 	delay(5); //消抖
		if(0==key1)
		{
			while(!key1); //松手检测
			if(key0_count==1)
			{
				second ++;
				if(60==second)	
					second = 0;
				 write_add(0x40+10,second);
			}
			if(key0_count==2)
			{
				minute ++;
				if(60==minute)	
					minute = 0;
				 write_add(0x40+7,minute);
			}
			if(key0_count==3)
			{
				hour ++;
				if(24==hour)	
					hour = 0;
				 write_add(0x40+4,hour);
			}
		}
	}
	if(0==key2) //第三个键被按下
	{
	 	delay(5); //消抖
		if(0==key2)
		{
			while(!key2); //松手检测
			if(key0_count==1)
			{
				second --;
				if(-1==second)	
					second = 59;
				write_add(0x40+10,second);	
			}
			if(key0_count==2)
			{
				minute --;
				if(-1==minute)	
					minute = 59;
				write_add(0x40+7,minute);	
			}
			if(key0_count==3)
			{
				hour --;
				if(-1==hour)	
					hour = 23;
				write_add(0x40+4,hour);	
			}
		}
	}

}
//程序初始化函数
void init()
{
	uchar i;
	hour = 0;
	minute = 0;
	second = 0;
	key0_count = 0;
	init1602();
	delay(20);  //延长时间,确保液晶处于非忙状态
	for(i=0;i<14;i++)
	{
		write_data_1602(table_date[i]);
		delay(5);	
	}
	write_cmd_1602(0x80+0x40+4);  //调整地址指针
	for(i=0;i<8;i++)
	{
		write_data_1602(table_time[i]);
		delay(5);	
	}
	//初始化定时器
	TMOD = 0x01;   //定时器模式
	TH0 = (65536-50000)/256;  //装初值
	TL0 = (65536-50000)%256;
	EA = 1;//开总中断
	ET0 = 1;//开定时器0中断
	TR0 = 1; //启动定时器,此时开始计时
}
void timer0() interrupt 1  //定时器0的中断处理函数
{
 	TH0 = (65536-50000)/256;  //装初值
	TL0 = (65536-50000)%256;
	timer_count ++;
	if(20==timer_count)		   //到了1秒更新时分秒的显示
	{
		timer_count = 0; //中断次数清0,重新计数
		second ++;   //秒针加1
		if(second==60)
		{
			second = 0;
			minute ++;	 //分针加1
			if(60==minute)
			{
			 	minute = 0;
				hour ++;  //小时加1
				if(24==hour)
				{
					hour = 0;
				}
				write_add(0x40+4,hour);
			}
			write_add(0x40+7,minute);  //更新分针的显示
		}
		write_add(0x40+10,second);  //更新秒针
	}
}