CT107D开发板 keyBoard.c

#include <reg52.h>

typedef unsigned char uint8_t;

sbit keyRow0 = P3^0;
sbit keyRow1 = P3^1;
sbit keyRow2 = P3^2;
sbit keyRow3 = P3^3;
sbit keyCol0 = P3^7;
sbit keyCol1 = P3^6;
sbit keyCol2 = P3^5;
sbit keyCol3 = P3^4;

code uint8_t keyNo[4][4] = {
    {7, 11, 15, 19},
    {6, 10, 14, 18},
    {5, 9, 13, 17},
    {4, 8, 12, 16}
};
pdata uint8_t keyState[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 keyAction(uint8_t keyCode);

void keyDriver() {  //在主循环中调用
    uint8_t i, j;
    static uint8_t backup[4][4] = { //矩阵按键上一次的状态
        {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++) //依次判断每一个按键
            if (keyState[i][j] != backup[i][j]) {   //如果这个按键当前的状态和上一次的状态不同
                if (keyState[i][j] == 0)    //如果当前的状态是按下去了（在按键的前沿触发执行程序）
                    keyAction(keyNo[i][j]);
                backup[i][j] = keyState[i][j];  //备份当前的状态
            }
}

void keyScan() {    //每执行一次扫一行，每一个按键的采样周期为4个定时器周期
    static uint8_t i = 0; //按键扫描的行索引
    static uint8_t keyBuf[4][4] = {   //每一个按键的流水时序采样状态，保存8个样本点
        {0xFF, 0xFF, 0xFF, 0xFF}, {0xFF, 0xFF, 0xFF, 0xFF},
        {0xFF, 0xFF, 0xFF, 0xFF}, {0xFF, 0xFF, 0xFF, 0xFF}
    };
    uint8_t j;    //按键扫描的列索引

	P3 = ~(1 << i);		//选择当前行（0有效）
    keyBuf[i][0] = (keyBuf[i][0] << 1) | keyCol0;   //流水保存采样结果
    keyBuf[i][1] = (keyBuf[i][1] << 1) | keyCol1;
    keyBuf[i][2] = (keyBuf[i][2] << 1) | keyCol2;
    keyBuf[i][3] = (keyBuf[i][3] << 1) | keyCol3;
    for (j = 0; j < 4; j++) {   //读取当前行各按键的采样信息，由此更新按键的当前状态
        if ((keyBuf[i][j] & 0x0F) == 0x00)   //取最近的4个样本点，这里一定要加括号，否则编译会出问题
            keyState[i][j] = 0;
        else if ((keyBuf[i][j] & 0x0F) == 0x0F)
            keyState[i][j] = 1;
    }
    i = (i + 1) & 0x03; //切换至下一个行索引，为下一次扫描做好准备
}