#include<reg52.h> //包含头文件，一般情况不需要改动，头文件包含特殊功能寄存器的定义
#include<intrins.h>

sbit duan=P2^2;//定义锁存使能端口 段锁存
sbit wei=P2^3;//                 位锁存
sbit key1 = P1^1;
sbit key2 = P1^2;
sbit key3 = P1^3;
sbit key4 = P1^4;

unsigned char code duanma[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};// 显示段码值0~9
unsigned char code weima[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};//分别对应相应的数码管点亮,即位码
unsigned char temp[8]; //存储显示值的全局变量
char hour; minute; second, num, t, i;

void delay(unsigned int t); //函数声明
void Display(unsigned char FirstBit,unsigned char Num);
void initial();
void delay20ms();
void keyscan();
void caifen();
void display();
/*------------------------------------------------
                    主函数
------------------------------------------------*/
main()
{
	initial();
    
	  while(1)
      {
		
		keyscan();
		caifen();
		display();
      }		
}

void initial()
{
	TMOD = 0x01;
	TH0 = (65536 - 2000)/256;
	TL0 = (65536 - 2000)%256;
	EA = 1;
	TR0 = 1;
	ET0 = 1;
	hour = 23;
	minute = 59;
	second = 57;
}


void time0(void) interrupt 1
{
	TH0 = (65536 - 2000)/256;
	TL0 = (65536 - 2000)%256;

	num ++;
	if (num == 500)
	{
		num = 0;
		second ++;
		if (second == 60)
		{
			second = 0;
			minute ++;
			if (minute == 60)
			{
				
			   
				minute = 0;
				hour ++;
				if (hour == 24)
				{
					hour = 0;
				}
			}
		}
	}
				
} 	

void keyscan()
{
		if(key1 == 0)
		{
			delay20ms();
			while(key1 == 0);							
				TR0 = 0;
				t ++;										
		}
			   	
		switch(t)
		{
			case 1:
			if(key2 == 0)
			{
				delay20ms();
				if(key2 == 0)
				{
					while(key2 == 0);
					hour ++;
					if(hour == 24)
					{
						hour = 0;
					}
				}
			}
			
			if(key3 == 0)
			{
				delay20ms();
				if(key3 == 0)
				{
					while(key3 == 0);
					hour --;
					if(hour == -1)
					{
						hour =23;
					}
				}
			}

			break;

			case 2:
			
			if(key2 == 0)
			{
				delay20ms();
				if(key2 == 0)
				{
					while(key2 == 0);
					minute ++;
					if(minute == 60)
					{
						minute = 0;
					}
				}
			}
			if(key3 == 0)
			{
				delay20ms();
				if(key3 == 0)
				{
					while(key3 == 0);
					minute --;
					if(minute == -1)
					{
						minute = 59;
					}
				}
			}
			break;
			
			case 3:
			TR0 = 1;
			t = 0; 
			break;
			
			default:
			break;
			
		}	
}

void caifen()
{
	
		
		 temp[0]=duanma[hour/10]; //时			//数据的转换，因我们采用数码管0~9的显示,将数据分开
		 temp[1]=duanma[hour%10];
		 temp[2]=0x40;					    	        //加入"-"
		 temp[3]=duanma[minute/10];//分
	  	 temp[4]=duanma[minute%10];
		 temp[5]=0x40;
		 temp[6]=duanma[second/10];//秒
		 temp[7]=duanma[second%10];		
}

void display()
{
	
		for (i = 0; i < 8; i ++)
		{
		   wei=1;     //位锁存
	       P0=weima[i]; //取位码 
	       wei=0;
	
	       duan=1;     //段锁存 
	       P0=temp[i]; //取显示数据，段码
	       duan=0;
       	   delay(310);
		}
}

void delay20ms(void)   //误差 20us
{
    unsigned char a,b;
    for(b=215;b>0;b--)
        for(a=45;a>0;a--);
    _nop_;  //if Keil,require use intrins.h
    _nop_;  //if Keil,require use intrins.h
}



void delay(unsigned int i)
{
	while (i --);
}