#include <reg51.h>
#include"key.h"
#include"includes.h"
#include <intrins.h>
/*char read_key(unsigned char temp)
{
static char key_state=0;
char key_press,key_return=0;
key_press=temp;
switch(key_state){
case key_state_0:if(!key_press)key_state=key_state_1;break;
case key_state_1 :if(!key_press)
{
key_return=1;
key_state=key_state_2;
}
else key_state=key_state_0;break;
case key_state_2:if(key_press)key_state=key_state_0;break;
}
return key_return;
} */
#define No_key 255
#define K1_1 1
#define K1_2 2
#define K1_3 3
#define K2_1 4
#define K2_2 5
#define K2_3 6
#define K3_1 7
#define K3_2 8
#define K3_3 9
#define K4_1 10
#define K4_2 11
#define K4_3 12
#define Key_mask 0X07
char read_keyboard()
{
static unsigned char key_state = 0, key_value, key_line;
char key_return = No_key,j,temp;
switch (key_state)
{
case 0:
key_line = 0x08;
for (j=1; j<=4; j++) // 扫描键盘
{
P1 = ~key_line; // 输出行线电平
temp= P1;
key_value = Key_mask &temp ; // 读列电平
if (key_value == Key_mask)
key_line <<= 1; // 没有按键,继续扫描
else
{
key_state++; // 有按键,停止扫描
break; // 转消抖确认状态
}
}
break;
case 1:
temp= P1;
if (key_value == (Key_mask & P1)) // 再次读列电平,
{
switch (key_line | key_value) // 与状态 0 的相同,确认按键
{ // 键盘编码,返回编码值
case 0x0e:
key_return = K1_1;
break;
case 0x0d:
key_return = K1_2;
break;
case 0x0b:
key_return = K1_3;
break;
case 0x16:
key_return = K2_1;
break;
case 0x15:
key_return = K2_2;
break;
case 0x13:
key_return = K2_3;
break;
case 0x26:
key_return = K3_1;
break;
case 0x25:
key_return = K3_2;
break;
case 0x23:
key_return = K3_3;
break;
case 0x46:
key_return = K4_1;
break;
case 0x45:
key_return = K4_2;
break;
case 0x43:
key_return = K4_3;
break;
}
key_state++; // 转入等待按键释放状态
}
else
key_state--; // 两次列电平不同返回状态 0,(消抖处理)
break;
case 2: // 等待按键释放状态
P1 = 0x07; // 行线全部输出低电平
temp= P1;
if ( (Key_mask & temp) == Key_mask)
key_state=0; // 列线全部为高电平返回状态 0
break;
}
return key_return;
}
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