44key.c

SHT10温湿度测试

#include "reg52.h"

unsigned char key;
static unsigned int j;

static void mDelay(j)
{
    unsigned int i;
	for(;j>0;j--)
	{
	    for(i=124;i>0;i--)
		{;}
	}
}

unsigned char KeyScan(void)
{
    unsigned char temp;
	P2=0x0f;
	temp=P2;				
	if((temp&0x0f)!= 0x0f)
	{
	    mDelay(10);
	    if((temp&0x0f)!=0x0f)
		{
	        P2=0xef;
	        mDelay(1);
	        temp=P2;
	        temp&=0x0f;//扫描第1列
	        if(temp!=0x0f)
			{	 
	            switch(temp)
				{
		            case 0x0e:key=1;break;
		            case 0x0d:key=5;break;
		            case 0x0b:key=9;break;
		            case 0x07:key=13;break;
		            default:break;
                }
            }
	        mDelay(2);
	        P2=0xdf;//第2列
	        mDelay(1);
	        temp=P2;
	        temp&=0x0f;
	        if(temp!=0x0f)
			{	 
	            switch(temp)
				{
		            case 0x0e:key=2;break;
		            case 0x0d:key=6;break;
		            case 0x0b:key=10;break;
		            case 0x07:key=14;break;
			        default:break;
	            }
            }
	        mDelay(2);
	        P2=0xbf;//第3列
	        mDelay(1);
	        temp=P2;
	        temp&=0x0f;
	        if(temp!=0x0f)
			{	 
	            switch(temp)
				{
		            case 0x0e:key=3;break;
		            case 0x0d:key=7;break;
		            case 0x0b:key=11;break;
		            case 0x07:key=15;break;
		         	default:break;
                }
            }
            mDelay(2);
	        P2=0x7f;//第4列
	        mDelay(1);
	        temp=P2;
	        temp&=0x0f;
	        if(temp!=0x0f)
			{	 
	            switch(temp)
				{
		            case 0x0e:key=4;break;
		            case 0x0d:key=8;break;
		            case 0x0b:key=12;break;
		            case 0x07:key=16;break;
			        default:break;
                }
            }
        }
    }
    return key;
}

unsigned char KeyFree(void)
{
	key=KeyScan();
	P2=0x0f;
	while(P2&0x0f!=0x0f){}
	return key;
}