单片机入门：数码管倒计时

#include<reg52.h>

typedef unsigned int u16;    //对数据类型进行声明定义
typedef unsigned char u8;

unsigned char LedBuff[]={
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
};

unsigned char code LedChar[]={
0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e
};//共阳

/*unsigned char code LedChar[]={
0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71
};//共阴*/

unsigned char cnt=0;
unsigned long sec=999999;
unsigned char i=0;

void delay(u16 i)
{
  while(i--);  
}

void main()
{  
  
  TMOD=0x01;
  TH0=0xEC;
  TL0=0x78;
  TR0=1;
  EA=1;
  ET0=1;
  
  while(1)
  {  
    if(cnt>=150)//溢出次1秒
    {
      cnt=0;
      sec--;
      LedBuff[0]= LedChar[sec%10];
      LedBuff[1]= LedChar[sec/10%10];
      LedBuff[2]= LedChar[sec/100%10];
      LedBuff[3]= LedChar[sec/1000%10];
      LedBuff[4]= LedChar[sec/10000%10];
      LedBuff[5]= LedChar[sec/100000%10];
    }
 }    
}
void InterruptTimer0()  interrupt 1
{
    TH0=0XEC;
    TL0=0X78;//计时器溢出一次0.001秒
    cnt++;
    P0=0xFF;
    for(i=0;i<6;i++)
    {
      P0=0xff;
      
      switch(i)   //位选，选择点亮的数码管，
      {
        case(0):
          P1=0x20; break;//显示第0位
        case(1):
          P1=0x10; break;//显示第1位
        case(2):
          P1=0x08; break;//显示第2位
        case(3):  
          P1=0x04; break;//显示第3位
        case(4):
          P1=0x02; break;//显示第4位
        case(5):
          P1=0x01; break;//显示第5位
        default: break;
      }
      P0=LedBuff[i];//发送段码
      delay(10); //间隔一段时间扫描  
      P0=0xFF;
    }
}