#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 KeySta[4][4] = {
{1,1,1,1},{1,1,1,1},{1,1,1,1},{1,1,1,1}
};
unsigned char code KeyCodeMap[4][4] = { //矩阵按键编号到标准键盘键码的映射表
{ 0x31, 0x32, 0x33, 0x26 }, //数字键1、数字键2、数字键3、向上键
{ 0x34, 0x35, 0x36, 0x25 }, //数字键4、数字键5、数字键6、向左键
{ 0x37, 0x38, 0x39, 0x28 }, //数字键7、数字键8、数字键9、向下键
{ 0x30, 0x1B, 0x0D, 0x27 } //数字键0、ESC键、 回车键、 向右键
};
void KeyDriver();
void main()
{
EA = 1; //使能总中断
TMOD = 0x01; //设置T0为模式1
TH0 = 0xFC; //为T0赋初值0xFC67，定时1ms
TL0 = 0x67;
ET0 = 1; //使能T0中断
TR0 = 1; //启动T0
while (1)
{
KeyDriver(); //调用按键驱动函数
}
}
void KeyAction(unsigned char keycode) //按键处理函数,根据不同键值执行动作
{
if((keycode >= 0x30) &&(keycode <= 0x39)) //数字键
{
}
else if(keycode == 0x26) //向上键
{
}
else if(keycode == 0x25) //向左键
{
}
else if(keycode == 0x28) //向下键
{
}
else if(keycode == 0x27) //向右键
{
}
else if(keycode == 0x0D) //回车键
{
}
else if(keycode == 0x1B) //ESC键
{
}
}
void KeyDriver()
{
unsigned char i, j;
static unsigned char backup [4][4] = {
{1,1,1,1},{1,1,1,1},{1,1,1,1},{1,1,1,1}
};
for(i=0; i<4; i++)
{
for(j=0; j<4; j++)
{
if(backup[i][j] != KeySta[i][j])
{
if(backup[i][j] == 0)
{
KeyAction(KeyCodeMap[i][j]);
}
backup[i][j] = KeySta[i][j];
}
}
}
}
/* 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 = 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;
}
}
/* T0中断服务函数，用于数码管显示扫描与按键扫描 */
void InterruptTimer0() interrupt 1
{
TH0 = 0xFC;
TL0 = 0x67;
KeyScan();
}
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