一种非传统的矩阵键盘扫描函数

#define scan_key_port P3

uchar key_scan()
{
uchar sccode,recode;
uchar key_value;
scan_key_port=0xf0; /* 发全 "0" 的行扫描码，列线输入 */
if((scan_key_port&0xf0)!=0xf0) /* 若有键按下 */
{
delay_1ms(1); /*延时去抖动*/
if((scan_key_port&0xf0)!=0xf0) /* 若有键按下 */
{
sccode=0xfe; /*逐行扫描初值*/
while((sccode&0x10)!=0)
{
scan_key_port=sccode; /* 输出行扫描码 */
if((scan_key_port&0xf0)!=0xf0) /* 本行有键按下 */
{
recode=(scan_key_port&0xf0)|0x0f;
key_value=(~sccode)+(~recode);/* 返回特征码 */
}
else sccode=(sccode<1)|0x01; /* 行扫描左移一位 */
}
}
}
else { //若无键按下
scan_key_port = 0xff;
return (0);
}
scan_key_port = 0xff; /*释放按键扫描端口*/
switch(key_value){ /*显示adclass=0&app_id=0&c=news&cf=1001&ch=0&di=128&fv=17&is_app=0&jk=eda4a0003316455c&k=%B0%B4%BC%FC&k0=%B0%B4%BC%FC&kdi0=0&luki=1&n=10&p=baidu&q=98059059_cpr&rb=0&rs=1&seller_id=1&sid=5c451633a0a4ed&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1831118&u=http%3A%2F%2Fwww%2E51hei%2Ecom%2Fmcu%2F2075%2Ehtml&urlid=0" id="0_nwl" mpid="0" target="_blank">按键对应的丝印*/
case 0x11:
return(0);

case 0x12:
return(1);

case 0x14:
return(2);

case 0x21:
return(3);

case 0x22:
return(4);

case 0x24:
return(5);

case 0x41:
return(6);

case 0x42:
return(7);

case 0x44:
return(8);

case 0x81:
return(9);

case 0x82:
return(A);

case 0x84:
return(B);

case 0x18:
return(C);

case 0x28:
return(D);

case 0x48:
return(E);

case 0x88:
return(F);
}
}