我想做一个简单的红绿灯，绿灯亮，数码管从90减到0，然后绿灯关闭，红灯亮，数码管再从90减到0，调试了半天转到红灯亮的时候就停止了，数码管不减了，哪位大虾帮帮忙看看怎么回事？
程序如下： #include<reg52.h>
#define uchar unsigned char;
#define uint unsigned int;
sbit green=P1^2;
sbit red=P1^0;
sbit dula=P2^6;
sbit wela=P2^7;
uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
unsigned char temp,shi,ge,t0,t1,flag,flag1,aa,bb,temp1;
void display1(unsigned char aa,unsigned char bb);
void delay(unsigned int z);
void init();
void display(unsigned char shi,unsigned char ge);
void main()
{
  init();
while(1)
{        
        if(flag1!=1)
        {
        green=0;               
        display(shi,ge);
        P2=0xff;
        }
        else
        {
        temp1=90;
         red=0;
        display1(aa,bb);
        }
       
       
       
            
}


}

void display(unsigned char  shi,unsigned char ge)
{
shi=temp/10;
ge=temp%10;


dula=1;
P0=table[shi];
dula=0;
P0=0xff;
wela=1;
P0=0xfe;
wela=0;
delay(1);




dula=1;
P0=table[ge];
dula=0;
P0=0xff;
wela=1;
P0=0xfd;
wela=0;
delay(1);
}


void display1(unsigned char aa,unsigned char bb)
{
aa=temp1/10;
bb=temp1%10;
wela=1;
P0=0xfe;
wela=0;
P0=0xff;
dula=1;
P0=table[aa];
dula=0;
delay(1);

wela=1;
P0=0xfd;
wela=0;
P0=0xff;
dula=1;
P0=table[bb];
dula=0;
delay(1);
}


void delay(unsigned int z)
{
unsigned int x,y;
for(x=z;x>0;x--)
for(y=110;y>0;y--)
;
}
void timer0() interrupt 1
{
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
   t0++;
   if(flag!=1)
   {
   if(t0==20)
   {
   t0=0;
   temp--;
   if(temp==0)
  {          
      P2=0xff;

}
}
}
else
  {
  green=1;
  if(t0==20)
  {
  t0=0;
  temp1--;
  if(temp1==0)
  {
  P2=0xff;
  }
  }
  flag1=1;
}

}
void timer1() interrupt 3
{
TH1=(65536-50000)/256;
TL1=(65536-50000)%256;
t1++;
if(t1==1820)
{
t1=0;
TR0=0;
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
TR0=1;
flag=1;
t0=0;
}

}
void init()
{
temp=90;
temp1=90;
TMOD=0x11;
TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
TH1=(65536-50000)/256;
TL1=(65536-50000)%256;
EA=1;
ET0=1;
ET1=1;
TR1=1;
TR0=1;
}