/*******************************************************************************
  Title:  演示程序5 - 按键检测				                     				*
  Name:   ex05.c                                                            	*
  Date:   2005-5-5                                                             	*
  Ver:    1.0                                                                  	*                                                *
  web：   http://www.mcustudy.com                                               *
********************************************************************************
*  描述:                                                                       *
*         按键扫描程序                                                         *
*         上电时, 点亮P00口LED                                                 *
*         按下K1时, LED向右移一位                                              *
*         按下K2时, LED向左移一位                                              *
*******************************************************************************/

#include <reg51.h>
#include <intrins.h>


sbit	K1 = P3^2;
sbit	K2 = P3^3;

unsigned char scan_key()
{
	unsigned char key_s;
	key_s = 0x00;
	key_s |= K2;
	key_s <<= 1;
	key_s |= K1;
	return key_s;		
}

void proc_key(unsigned char key_v)
{
	if((key_v & 0x01) == 0)
	{
		P0 = _cror_(P0,1);
	}
	else if((key_v & 0x02) == 0)
	{
		P0 = _crol_(P0, 1);
	}
}

void delayms(unsigned char ms)	// 延时子程序

{						
	unsigned char i;
	while(ms--)
	{
		for(i = 0; i < 120; i++);
	}
}



main()
{
	
	unsigned char key_s,key_v;
	key_v = 0x03;
	P0 = 0xfe;
	while(1)
	{
		key_s = scan_key();
		if(key_s != key_v)
		{
			delayms(20);
			key_s = scan_key();
			if(key_s != key_v)
			{	
				key_v = key_s;
				proc_key(key_v);
				delayms(150);	
			}
		}
	}	
}