led.c

单片机开发资料光盘-双龙-686M.zip

#include <AT89X52.H>
void Delay(void)
	{
	unsigned int a, b;
	for (a=0;a<250;a++)
	    {	      
	      for (b=0;b<250; b++)
	         ;
	     }		
	}
void LED_On(unsigned char i)
	{
	P0=~(1<<i); 
	P2=~(1<<i);
	P1=~(1<<i);
	Delay();
	}

void main(void)
	{
	int i;
    P0=0xff;
    P1=0xff;
	P2=0xff;
    P3=0xff;
   	while (1)
		{
		for (i = 0; i < 8; i++)
			LED_On(i);
			for (i = 8; i > 0; i--)
			LED_On(i);
		for (i = 0; i < 8; i += 2)
			LED_On(i);
		for (i = 7; i > 0; i -= 2)
			LED_On(i);
		}
	}