Single chip traffic light C language program

   This is a C language program for a single-chip traffic light. The single-chip is AT89C51. Two common cathode two-in-one digital tubes display the countdown of two intersections respectively. 12 light-emitting diodes are used to simulate red, yellow and green lights. The circuit is simple and easy to make. Small electronic production .

#include
#define uchar unsigned char
bit flag;
sbit red1_1=P1^0;   //North-South red light D1
sbit yel1_1=P1^1;  //North-South yellow light D2
sbit gre1_1=P1^2;  //North-South green light D3
sbit red1_2=P1^3;  //North-South red light D4
sbit yel1_2=P1^4;  //North-South yellow light D5
sbit gre1_2=P1^5;  //North-South green light D6

sbit red2_1=P1^6;  //East-West red light D7
sbit yel2_1=P1^7;  //East-West yellow light D8
sbit gre2_1=P0^0;  //East-West green light D9
sbit red2_2=P0^1;  //East-West red light D10
sbit yel2_2=P0^2;  //East-West yellow light D11
sbit gre2_2=P0^3;  //East-West green light D12

flying code tab[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x83,0xf8,0x80,0x98};
fly n,n1,aa=0,shi,ge,shi1,ge1;
void init();
void xianshi1(fly shi,fly ge);
void xianshi2(flying shi1,flying ge1);
void delay(fly z)
{
 fly x,y;
 for(x=z;x>0
   ;x--) for(y=110;y>0;y--);
}
main()
{
 n=30;
   sh=n/10;
 ge=n;
   n1=30;
   shi1=n1/10;
 ge1=n1;

    init();
  while(1)
     {
     if(flag!=1)
      xianshi1(shi,ge);
   else
           xianshi2(shi1,ge1);
  
  }
}

void xianshi1(uchar shi,uchar ge)
{
    P3=0x02;
    P2=tab[ge];
    delay(200);
    P3=0x01;
    P2=tab[shi];
    delay(200);
}

//  http://www.duankudp.com/
void xianshi2(uchar shi1,uchar ge1)
{
 P3=0x08;
 P2=tab[ge1];
    delay(200);
    P3=0x04;
    P2=tab[shi1];
    delay(200);

}

void init()
{ 
 TMOD=0x01;
 TH0=(65536-50000)/256;
 TL0=(65536-50000)%6;
 EA=1;
 ET0=1;
 TR0=1;
}

void timer0() interrupt 1
{
 TH0=(65536-50000)/256;
 TL0=(65536-50000)%6;
 aa++;
   if(flag!=1)
     { 
   if(aa==20)
     {
        aa=0;
                    red1_1=0;red1_2=0;
                    gre2_1=0;gre2_2=0;  //Start the north-south red light 1 and the east-west green light 2    

        n--;
                 shi=n/10;
        ge=n;

               if(n<=3)
                  {
      red1_1=0;red1_2=0;
      gre2_1=1;gre2_2=1;
                    yel2_1=0;yel2_2=0;//Start the north-south red light 1 and the east-west yellow light 2
     
                   if(n<=0)
          {
                      n=30;          
                         red1_1=1;red1_2=1;
       gre1_1=0;gre1_2=0;
       yel2_1=1;yel2_2=1;
       red2_1=0;red2_2=0;//Start the north-south green light 1 and the east-west red light 2 http://www.5imcu.net/
 
                       TR0=0;
                         TH0=(65536-50000)/256;
                      TL0=(65536-50000)%6;
          TR0=1;
                         aa++;
          flag=1;

                }
                   }
               }
     }
   else
   {
      if(flag==1)
        {   
          //   TH0=(65536-50000)/256;
       //   TL0=(65536-50000)%6;
       //   TR0=1;
          //   aa++;
          if(aa==20)
     {
           aa=0;                       
                 n1--;
                 shi1=n1/10;
                   ge1=n1;
        if(n1<=3)
         {
   gre1_1=1;gre1_2=1;
            yel1_1=0;yel1_2=0;
           red2_1=0;red2_2=0;//Start the north-south yellow light 1 and the east-west red light 2
                                 
                if(n1<=0)
       {
          n1=30;
                         yel1_1=1;yel1_2=1;
                         red2_1=1;red2_2=1;

                 TR0=0;
               TH0=(65536-50000)/256;
               TL0=(65536-50000)%6;
               TR0=1;
                 flag=0;
               }
                   }
                }
         }
     }
}