STC89C52单片机学习（一）----点亮LED

1.通过数组实现led流水灯 

#include

int m;

unsigned char code leds[8] = {0x7f, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd, 0xfe};

void delay(unsigned int i)

{

unsigned int j;

unsigned char k;

for(j=i; j>0; j--)

for(k=125; k>0 ;k--);

}

int main()

{

while(1)

{

for(m = 0; m < 8; m++)

{

P1 = leds[m];

delay(500);

}

}

return 0;

}

  使用 if语句实现led灯的控制，i类似于标志位控制进行循环转移

i = 0;

while(1)

{

P1 = leds[i++];

delay(5000);

if(i == 8) i = 0;

}

2.通过独立按键实现LED灯的闪烁流动

运用独立按键需I/O端口，预先置高，表示作为输入端

#include

sbit k1 = P3^4;

unsigned int m;

unsigned char code leds[8] = {0x7f, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd, 0xfe};

void delay(unsigned int i)

{

unsigned int j;

unsigned char k;

for(j=i; j>0; j--)

for(k=125; k>0; k--);

}

int main()

{

k1 = 1;

while(1)

{

for(m = 0; m < 8; )

{

P1 = leds[m];

delay(500);

if(k1 == 0)

{

delay(80);

if(k1 == 0)

m++;

}

}

}

return 0;

}

3.外部中断1实现按键闪烁

1）.实现部分在中断函数里

#include

sbit p3_4 = P3^4;

unsigned int m;

unsigned char code leds[8] = {0x7f, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd, 0xfe};

void delay(unsigned int i)

{

unsigned int j;

unsigned char k;

for(j=i; j>0; j--)

for(k=125; k>0; k--);

}

int main()

{

EA = 1;

EX1 = 1;

IT1 = 1;

p3_4 = 0;

P1 = leds[0];

while(1);

return 0;

}

void led_key() interrupt 2

{

if(m <= 7)

{

P1 = leds[m++];

delay(500);

//m++;

}

else

		P1 = leds[0];			

}

2)实现部分在主函数中
bit flag;         //标志位
 
 
while(1)
{
	for(m = 0; m < 8; )
	{
		P1 = leds[m];
		delay(500);	
 
		if(flag == 1)
		{
			delay(80);			 //去抖 -----中断
			if(flag == 1)
				m++;	
		}			
	}		
}
 
 
void led() interrupt 0
{
	flag = 1;
}