【单片机】P3口输入，P1口输出

• 代码详解（方法一）
• 代码详解（方法二）

代码详解（方法一）

#include <reg51.h>
#include <intrins.h>
//功能:P3口输入，P1口输出

#define uchar unsigned char
unsigned char code mon51[3] _at_ 0x3b; //保留0x3B开始三个程序空间作全速中断用

sbit flag = P3 ^ 3;
uchar judge = 0;
uchar y = 1;
void delay(unsigned int i)
{ 
   unsigned int j, k;
   for (k = 0; k < i; k++)
      for (j = 0; j < 1000; j++)
         ;
}
void main(void)
{ 
   uchar aa;

   P1 = 0xff; //P1口初始化
   aa = 0xfe; //变量赋值

   while (1)
   { 
      if (!judge && flag == 1)
         judge = 1;
      else if (judge && flag == 0)
      { 
         y <<= 1;
         judge = 0;
      }
      P1 = ~y;
      if (y == 128)
         y = 1;
      delay(10);
   }
}

代码详解（方法二）

#include <reg51.h>
#include <intrins.h>
//功能:P3口输入，P1口输出

#define uchar unsigned char
unsigned char code mon51[3] _at_ 0x3b; //保留0x3B开始三个程序空间作全速中断用

sbit P3_3 = P3 ^ 3;
uchar led = 0x00;

void delay(unsigned int i)
{ 
	unsigned int j, k;
	for (k = 0; k < i; k++)
		for (j = 0; j < 1000; j++)
			;
}
void main(void)
{ 
	P1 = 0xFF;
	while (1)
	{ 
		if (P3_3 == 0)
		{ 
			delay(50);
			if (P3_3 == 0)
			{ 
				led = led + 1;
				P1 = ~led;
				while (P3_3 == 0)
				{ 
				}
			}
		}
	}
}