up51s005.c

此代码为按键扫描程序

/*******************************************************************************
*                                                                              *
*    File       : uP51s005.c                                                   *
*    Date       : 2004-9-5                                                     *
*    Version    : 1.0                                                          *
*                                                                              *
*    Author     : kevin           [e-mail]                               *
*    Company    : Http://www.dz51.com                                          *
*                                                                              *
********************************************************************************
*    Description:                                                              *
*                按键扫描程序                                                  *
*                上电时, 点亮P00口LED                                          *
*                按下AN1时, LED向下移一位                                      *
*                按下AN2时, LED向上移一位                                      *
*******************************************************************************/
#include <reg51.h>
#include <intrins.h>

unsigned char scan_key();
void proc_key(unsigned char key_v);
void delayms(unsigned char ms);

sbit	AN1 = P3^2;
sbit	AN2 = P3^3;
unsigned char leddata=0xfe;
main()
{
	
	unsigned char key_s,key_v;
	key_v = 0x03;
	P0 = leddata;
	while(1)
	{
		key_s = scan_key();
		if(key_s != key_v)
		{
			delayms(10);
			key_s = scan_key();
			if(key_s != key_v)
			{	
				key_v = key_s;
				proc_key(key_v);					
			}
		}
	}	
}

unsigned char scan_key()
{
	unsigned char key_s;
	key_s = 0x00;
	key_s |= AN2;
	key_s <<= 1;
	key_s |= AN1;
	return key_s;		
}

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

void delayms(unsigned char ms)	
// 延时子程序
{						
	unsigned char i;
	while(ms--)
	{
		for(i = 0; i < 120; i++);
	}
}