流水灯

#include<reg52.h>

sbit P20 = P2^0;
sbit P21 = P2^1;
sbit P22 = P2^2;
sbit ENLED = P1^1;

void main()

{
unsigned int i = 0;
unsigned char cnt = 0;

P20 = 0;
P21 = 1;
P22 = 1;
ENLED = 0;

while (1)
{
  P0 = ~(0x01<<cnt);
  for(i = 0;i<50000;i++);
  cnt++;
  if(cnt >= 8)
  {
   cnt=0;
  }
}
}