按键

ID:359754 · 发表于 2018-6-26 22:06

#include <reg52.h>

sbit KEY_IN_1  = P2^4;
sbit KEY_IN_2  = P2^5;
sbit KEY_IN_3  = P2^6;
sbit KEY_IN_4  = P2^7;
sbit KEY_OUT_1 = P2^3;
sbit KEY_OUT_2 = P2^2;
sbit KEY_OUT_3 = P2^1;
sbit KEY_OUT_4 = P2^0;

unsigned char code KeyCodeMap[4][4] = { //矩阵按键编号到标准键盘键码的映射表
{ '1',  '2',  '3', 0x26 }, //数字键1、数字键2、数字键3、向上键
{ '4',  '5',  '6', 0x25 }, //数字键4、数字键5、数字键6、向左键
{ '7',  '8',  '9', 0x28 }, //数字键7、数字键8、数字键9、向下键
{ '0', 0x1B, 0x0D, 0x27 }  //数字键0、ESC键、  回车键、向右键
};

unsigned char pdata KeySta[4][4] = {  //全部矩阵按键的当前状态
{1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1}
};
extern void Reset();
extern void GetResult();
extern void NumKeyAction(unsigned char n);
extern void OprtKeyAction(unsigned char type);
extern void LcdShowStr(unsigned char x, unsigned char y, unsigned char *str);

void KeyAction(unsigned char keycode)
{
if((keycode >= '0') && (keycode <= '9'))
{
NumKeyAction(keycode - '0');
}
else if(keycode == 0x26)
{
OprtKeyAction(0);
}
else if(keycode == 0x28)
{
OprtKeyAction(1);
}
else if(keycode == 0x25)
{
OprtKeyAction(2);
}
else if(keycode == 0x27)
{
OprtKeyAction(3);
}
else if(keycode == 0x0D)
{
GetResult();
}
else if(keycode == 0x1B)
{
Reset();
LcdShowStr(15, 1, "0");
}
}
/* 按键驱动函数，检测按键动作，调度相应动作函数，需在主循环中调用 */
void KeyDriver()
{
unsigned char i, j;
static unsigned char pdata backup[4][4] = {  //按键值备份，保存前一次的值
      {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1}
};

for (i=0; i<4; i++)  //循环检测4*4的矩阵按键
{
      for (j=0; j<4; j++)
      {
         if (backup[i][j] != KeySta[i][j]) //检测按键动作
         {
            if (backup[i][j] != 0)          //按键按下时执行动作
            {
                  KeyAction(KeyCodeMap[i][j]); //调用按键动作函数
            }
            backup[i][j] = KeySta[i][j];    //刷新前一次的备份值
         }
      }
}
}

/* 按键扫描函数，需在定时中断中调用，推荐调用间隔1ms */
void KeyScan()
{
unsigned char i;
static unsigned char keyout = 0; //矩阵按键扫描输出索引
static unsigned char keybuf[4][4] = {  //矩阵按键扫描缓冲区
      {0xFF, 0xFF, 0xFF, 0xFF},  {0xFF, 0xFF, 0xFF, 0xFF},
      {0xFF, 0xFF, 0xFF, 0xFF},  {0xFF, 0xFF, 0xFF, 0xFF}
};

//将一行的4个按键值移入缓冲区
keybuf[keyout][0] = (keybuf[keyout][0] << 1) | KEY_IN_1;
keybuf[keyout][1] = (keybuf[keyout][1] << 1) | KEY_IN_2;
keybuf[keyout][2] = (keybuf[keyout][2] << 1) | KEY_IN_3;
keybuf[keyout][3] = (keybuf[keyout][3] << 1) | KEY_IN_4;
//消抖后更新按键状态
for (i=0; i<4; i++)  //每行4个按键，所以循环4次
{
      if ((keybuf[keyout][i] & 0x0F) == 0x00)
      { //连续4次扫描值为0，即4*4ms内都是按下状态时，可认为按键已稳定的按下
         KeySta[keyout][i] = 0;
      }
      else if ((keybuf[keyout][i] & 0x0F) == 0x0F)
      { //连续4次扫描值为1，即4*4ms内都是弹起状态时，可认为按键已稳定的弹起
         KeySta[keyout][i] = 1;
      }
}
//执行下一次的扫描输出
keyout++;       //输出索引递增
keyout &= 0x03; //索引值加到4即归零
switch (keyout) //根据索引，释放当前输出引脚，拉低下次的输出引脚
{
      case 0: KEY_OUT_4 = 1; KEY_OUT_1 = 0; break;
      case 1: KEY_OUT_1 = 1; KEY_OUT_2 = 0; break;
      case 2: KEY_OUT_2 = 1; KEY_OUT_3 = 0; break;
      case 3: KEY_OUT_3 = 1; KEY_OUT_4 = 0; break;
      default: break;
}

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