#include "keyScan.h"
#include <reg51.h>
#define KEY_BOARD P1
#define DELAY_VALUE 500
/*****************
延时子程序
*****************/
void delay()
{
unsigned short data i;
for(i = DELAY_VALUE;i != 0;i--);
}
/**********************
取得当前按键码
**********************/
unsigned char getKey()
{
unsigned char data keyState,scan,count,keyCode;
keyCode = 0xff;
/*是否有键按下*/
KEY_BOARD = 0xf0;
keyState = KEY_BOARD | 0x0f;
keyState = ~keyState;
if(!keyState) return keyCode;
delay();
KEY_BOARD = 0xf0;
keyState = KEY_BOARD | 0x0f;
keyState = ~keyState;
if(!keyState) return keyCode;
/*键盘扫描*/
scan = 0xfe;
for(count = 0;count < 4;count++){
KEY_BOARD = scan;
scan <<= 1;
scan ++;
keyState = KEY_BOARD & 0xf0;
if(keyState){
switch(keyState){
case 0xe0:
keyCode = count;
break;
case 0xd0:
keyCode = count + 4;
break;
case 0xb0:
keyCode = count + 8;
break;
case 0x70:
keyCode = count + 12;
break;
}
}
if(keyCode != 0xff) break;
}
//等到按键松开
do{
KEY_BOARD = 0xf0;
keyState = KEY_BOARD | 0x0f;
keyState = ~keyState;
}while(keyState);
return keyCode;
} |
|
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