【单片机期中测试】11.交通灯

#include<reg52.h>
#define uc unsigned char
sbit red1=P0^0; // 南北指向
sbit yellow1=P0^1;
sbit green1=P0^2;
sbit red2=P0^3; // 东西指向
sbit yellow2=P0^4;
sbit green2=P0^5;
unsigned int i=0;
void aa() interrupt 1
{
  TH0=15536/256;
  TH0=15536%256;
  i++;
  if(i>1400) i=0;
  TF0=0;
}
void main()
{
  uc t;
  TMOD=0x01;
  TH0=15536/256;
  TH0=15536%256;
  ET0=1; EA=1;
  TR0=1;
  while(1)
  {
    P2=t/10*16+t%10;
    if(i<600)
    {
      green2=red1=0;
      yellow1=yellow2=green1=red2=1;
      t=30-i/20;
    }
    else if(i<700)
    {
      yellow1=yellow2=0;
      green1=green2=red1=red2=1;
      t=35-i/20;
    }
    else if(i<1300)
    {
      red2=green1=0;
      yellow1=yellow2=red1=green2=1;
      t=65-i/20;
    }
    else if(i<1400)
    {
      yellow1=yellow2=0;
      green1=green2=red1=red2=1;
      t=70-i/20;
    }
  }
}