51 single chip microcomputer traffic light program and simulation

#define uint unsigned int
#define uchar unsigned char
sbit red_nb = P0^0;
sbit green_nb = P0^1;
sbit yellow_nb = P0^2;

sbit red_dx = P0^3;
sbit green_dx = P0^4;
sbit yellow_dx = P0^5;

unsigned char code   Disp_Tab[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x40};  //Segment code control

unsigned char code   dispbit[8]={0xfe,0xfd,0xfb,0xf7,0xef,0xdF,0xbF,0x7F};   //bit selection control

unsigned char LedOut[4];

uchar switch_type = 1;
uchar Traffic_time = 0;
uchar ds_time = 0;
uchar i,t;

void delay(uint i)
{
    char j;
    for(i; i > 0; i--)
        for(j = 200; j > 0; j--);
}

void Traffic_Light()    // Define four status displays
{
 switch(switch_type)
 {
   case 1:
    for( i=0; i<4; i++)
      { 
       P1 = dispbit[i];   // Use table lookup method for bit selection
      P3 = LedOut[i];
     
      delay(100);
      }        // Make the digital tube scan and display continuously here

     red_nb = 0;    //North-South red light on, green light off, yellow light
     offgreen_nb = 1;
     yellow_nb = 1;
     
     red_dx = 1;     //East-West red light off, green light on, yellow light
     offgreen_dx = 0;
     yellow_dx = 1;
     if(Traffic_time != 30)
     {
    LedOut[0]=Disp_Tab[(35 - Traffic_time)0/10];    //Data displayed by digital tubeLedOut
     [1]=Disp_Tab[(35 - Traffic_time)];    
     LedOut[2]=Disp_Tab[(29 - Traffic_time)0/10];
    LedOut[3]=Disp_Tab[(29 - Traffic_time)];
        return;          //Return to case1
     }
     Traffic_time = 0;
     switch_type = 2;     //Enter the second statebreak
     ;

  case 2:
    for( i=0; i<4; i++)
      { 
     P1 = dispbit[i];   //Use table lookup method for bit selection
      P3 = LedOut[i];
      
      delay(100);
      } 
     red_nb = 0;    //North-South red light on, green light off, yellow light off
     green_nb = 1;
     yellow_nb = 1;
     
     red_dx = 1;     //East-West red light off, green light off, yellow light on
     green_dx = 1;
     
     if(Traffic_time != 6)    //Yellow light hold time
     { 
      if(Traffic_time != t)
      {
       t = Traffic_time;
       yellow_dx = ~yellow_dx;
        
     }
     {
    LedOut[0]=Disp_Tab[(5 - Traffic_time)0/10];
     LedOut[1]=Disp_Tab[(5 - Traffic_time)];    
     LedOut[2]=Disp_Tab[(5 - Traffic_time)0/10];
    LedOut[3]=Disp_Tab[(5 - Traffic_time)];
        return;
     }
     return; 
    }
     
       Traffic_time = 0;
    switch_type = 3;
       break;
     

  case 3:
  for( i=0; i<4; i++)
      { 
      P1 = dispbit[i];   //Use table lookup method for bit selection
      P3 = LedOut[i];
       
      delay(100);
      } 
     red_nb = 1;    //North-South red light is off, green light is on, and yellow light is off
     green_nb = 0;
     yellow_nb = 1;
     
     red_dx = 0;     //East-West red light is on, green light is off, and yellow light is off
     green_dx = 1;
     yellow_dx = 1;
     if(Traffic_time != 19)
     {  LedOut[0]=Disp_Tab[(24 - Traffic_time)0/10];
      LedOut[1]=Disp_Tab[(24 - Traffic_time)];    
      LedOut[2]=Disp_Tab[(18 - Traffic_time)0/10];
     LedOut[3]=Disp_Tab[(18 - Traffic_time)];
         return;
     }
     Traffic_time = 0;
     switch_type = 4;
     break;

  case 4:
  for( i=0; i<4; i++)
      { 
       P1 = dispbit[i];   //Use table lookup method for bit selection
      P3 = LedOut[i];
     
      delay(100);
      } 
     red_nb = 1;    //North-South red light is off, green light is off, and yellow light is on
     green_nb = 1;
     
     red_dx = 0;     //East-West red light is on, green light is off, and yellow light is off
     green_dx = 1;
     yellow_dx =1;

      if(Traffic_time != 6)    //黄等保持的时间
      { 
       if(Traffic_time != t)
       {
        t = Traffic_time;
        yellow_nb = ~yellow_nb;
        
     }
      LedOut[0]=Disp_Tab[(5 - Traffic_time)0/10];
       LedOut[1]=Disp_Tab[(5 - Traffic_time)];   
       LedOut[2]=Disp_Tab[(5 - Traffic_time)0/10];
      LedOut[3]=Disp_Tab[(5 - Traffic_time)];
      return; 
    }  
       Traffic_time = 0;
    switch_type = 1;
       break;   
    
     

   }
}

void main()
{
 TMOD = 0x01;
 TH0 = (65536 - 50000)/256;
 TL0 = (65536 - 50000)%6;
 EA = 1;    //Open the general interrupt
 ET0 = 1;   //Open the timer 0 interrupt
 TR0 = 1;   //Start the timer

 while(1)
 {
  Traffic_Light();

 }

}

void T0_time() interrupt 1
{
 TH0 = (65536 - 50000)/256;
 TL0 = (65536 - 50000)%6;
 ds_time++;
 if(ds_time == 20)
 {
  ds_time = 0;
  Traffic_time++; 
  
 }

}