#include <reg52.h>
void delay_ms(unsigned int count)//延时知函道数
{
unsigned int i,j;
for(i=0;i<count;i++)
for(j=0;j<120;j++);
}
void main(void)//主程回序答
{
while(1)
{
P1=0X0F;
delay_ms(7000);
P1=0XF0;
delay_ms(11000);
}
}