蓝桥杯国信长天单片机—独立按键和矩阵键盘模块（七）

独立按键模块

1-2短接实现矩阵按键；2-3短接实现独立按键。


案例：
独立按键，S6，打开所有LED ，S7，关闭所有LED。S4 ，打开蜂鸣器，S5，关闭蜂鸣器

    #include "reg52.h"  

    /** 独立按键接口 */
    sbit S7  = P3^0;
    sbit S6  = P3^1;
    sbit S5  = P3^2;
    sbit S4  = P3^3;

    //主函数
    void main(void)
    {
        while(1)
        {
            if(S7 == 0)
            {
                P2 = ((P2&0x1f)|0x80);
                P0 = 0xff;  //关闭所有LED
                P2 &= 0x1f;
            }
            if(S6 == 0)
            {
                P2 = ((P2&0x1f)|0x80);
                P0 = 0x00;  //打开所有LED
                P2 &= 0x1f;
            }
            if(S5 == 0)
            {
                P2 = ((P2&0x1f)|0xa0);
                P0 &= ~(0x01<<6);  //Close
                P2 &= 0x1f;
            }
            if(S4 == 0)
            {
                P2 = ((P2&0x1f)|0xa0);
                P0 |= (0x01<<6); //Open
                P2 &= 0x1f;
            }

        }
    }

    /*******************************************************************************
    * 文件名称：矩阵键盘实验
    * 实验目的：1.掌握矩阵键盘扫描的基本原理
    *           2.掌握按键扫描及消除抖动的基本原理
    * 程序说明：1.使用程序前，将跳线J2调整为KBD模式
    *           2.转接板上使用P4.4和P4.2代替P3.6 P3.7
    * 硬件环境：IAP15F2K61S2@11.0592MHz
    *******************************************************************************/

    #include "reg52.h"  //定义51单片机特殊功能寄存器
    #include "absacc.h"

    sfr AUXR = 0x8E;
    sfr P4   = 0xC0;    //P4
    sbit P42 = P4^2;
    sbit P44 = P4^4;
    //  0    1    2    3    4    5    6    7    8    9   熄灭
    code unsigned char tab[] = { 0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0xFF};
    unsigned char dspbuf[8] = {10,10,10,10,10,10,10,10};  //显示缓冲区
    unsigned char dspcom = 0;

    bit key_re;
    unsigned char key_press;
    unsigned char key_value;

    bit key_flag = 0;
    unsigned char intr = 0;

    unsigned char read_keyboard(void);
    void display();

    //主函数
    void main(void)
    {
        unsigned char key_temp = 0xff;

        AUXR |= 0x80;    //1T模式，IAP15F2K61S2单片机特殊功能寄存器

        TMOD &= 0xF0;
        TL0 = 0xCD;
        TH0 = 0xD4;
        TF0 = 0;
        TR0 = 1;
        ET0 = 1;
        EA = 1;

        while(1)
        {
            if(key_flag)
            {
                key_flag = 0;
                key_temp = read_keyboard();
                if(key_temp != 0xFF) {
                    dspbuf[7] = key_temp%10;
                    dspbuf[6] = key_temp/10;
                }
            }

        }
    }

    //定时器中断服务函数
    void isr_timer_0(void)  interrupt 1  //默认中断优先级 1
    {
        display();
        if(++intr == 10)  //1ms执行一次
        {
            intr = 0;
            key_flag = 1;  //10ms按键扫描标志位置1
        }
    }

    //读取矩阵键盘键值:转接板中使用P42和P44代替8051引脚
    //顺序中的P36和P37引脚
    unsigned char read_keyboard(void)
    {
        static unsigned char col;

        P3 = 0xf0;
        P42 = 1;
        P44 = 1;

        if((P3 != 0xf0)||(P42 != 0)||(P44 != 0)) //有按键按下
            key_press++;
        else
            key_press = 0;  //抖动

        if(key_press == 3)
        {
            key_press = 0;
            key_re = 1;

            if(P44 == 0)            col = 1;
            if(P42 == 0)            col = 2;
            if((P3 & 0x20) == 0)    col = 3;
            if((P3 & 0x10) == 0)    col = 4;

            P3 = 0x0F;
            P42 = 0;
            P44 = 0;

            if((P3&0x01) == 0)    key_value = (col-1);
            if((P3&0x02) == 0)    key_value = (col+3);
            if((P3&0x04) == 0)    key_value = (col+7);
            if((P3&0x08) == 0)    key_value = (col+11);
        }

        //连续三次检测到按键被按下，并且该按键已经释放
        P3 = 0x0f;
        P42 = 0;
        P44 = 0;

        if(((key_re == 1) && (P3 == 0x0f))&&(P42 == 0)&&(P44 == 0))
        {
            key_re = 0;
            return key_value;
        }

        return 0xff;  //无按键按下或被按下的按键未被释放
    }

    //显示函数
    void display(void)
    {
        P0 = 0xff;
        P2 = ((P2&0x1f)|0xE0);
        P2 &= 0x1f;

        P0 = 1<<dspcom;
        P2 = ((P2&0x1f)|0xC0);
        P2 &= 0x1f;

        P0 = tab[dspbuf[dspcom]];
        P2 = ((P2&0x1f)|0xE0);
        P2 &= 0x1f;

        if(++dspcom == 8) {
            dspcom = 0;
        }
    }