新手，求大神们看看程序指导一下，串口助手显示按键值.

只看该作者 · 2016-8-8 15:52

本帖最后由淡然处世于 2016-8-9 10:06 编辑

单片机P0口接的4*4键盘，P1 口接的3*3矩阵键盘，12MHZ晶振。
/*问题：按一下后串口助手一直刷新按键值，而且0  1 4 5 8 9 均不能正常显示*/
#include<reg52.h>
#define uchar unsigned char                      //宏定义，后面所有的uchar，均为 unsigned char
#define uint unsigned int                      // 宏定义，后面所有的uint，均为 unsigned int

uchar num;                                     //定义一个全局变量num

/*4*4矩阵键盘P0口，扫描函数*/
uchar keyscan1()
{
      uchar temp;
      P0 = 0xfe;                                                                      //1111 1110 第一列线输出一个低电平
      temp = P0;                                                                   //temp = 1111 1110
      temp = temp&0xf0;                                                       //1111 1110 & 1111 0000 = 1111 0000 =0xf0
      while((temp&0xf0) != 0xf0)                                        //当有按键按下，则P0值发生改变，
      {
            delay(5);                                                                   //延时ms
            temp = P0;
            temp = temp & 0xf0;
            while((temp&0xf0) != 0xf0)                                  //再次确认是否有按键按下
            {
                     temp = P0;                                                 //读取P0口的值
                     delay(5);                                                    //延时
                     switch(temp)                                              //进行键值判断
                     {
                              case 0xee:num = 0;  break;
                              case 0xde:num = 1;       break;
                              case 0xbe:num = 2;       break;
                              case 0x7e:num = 3;       break;

                     }

            while(temp != 0xf0)
                     {
                              temp = P0;
                              temp = temp&0xf0;
                     }
            }
      }
      P0 = 0xfd;                                                          // 1111 1101       第二列线输出一个低电平
      temp = P0;
      temp = temp&0xf0;
while((temp&0xf0) != 0xf0)
{
      delay(5);
      temp = P0;
      temp = temp&0xf0;
            while((temp&0xf0) != 0xf0)
            {
                     temp = P0;
                     delay(5);
                     switch(temp)
                     {
                              case 0xed:num = 4;       break;
                              case 0xdd:num = 5;       break;
                              case 0xbd:num = 6;       break;
                              case 0x7d:num = 7;       break;

                     }

            while(temp != 0xf0)
                     {
                                    temp = P0;
                                    temp = temp&0xf0;
                     }
            }
}
      P0 = 0xfb;                                                                      // 1111 1011  第三列线输出一个低电平
      temp = P0;
      temp = temp&0xf0;
while((temp&0xf0) != 0xf0)
{
      delay(5);
      temp = P0;
      temp = temp&0xf0;
            while((temp&0xf0) != 0xf0)
                     {
                                    temp = P0;
                                    delay(5);
                              switch(temp)
                     {
                              case 0xeb:num = 8;       break;
                              case 0xdb:num = 9;       break;
                              case 0xbb:num = 10; break;
                              case 0x7b:num = 11; break;
                     }

            while(temp != 0xf0)
                     {
                              temp = P0;
                              temp = temp&0xf0;
                     }
                     }
}
      P0 = 0xf7;                                                                               // 1111 0111 第四列输出一个低电平
      temp = P0;
      temp = temp&0xf0;
while((temp&0xf0) != 0xf0)
{
      delay(5);
      temp = P0;
      temp = temp&0xf0;
            while((temp&0xf0) != 0xf0)
            {
                     temp = P0;
                     delay(5);
                     switch(temp)
                     {
                              case 0xe7:num = 12;break;
                              case 0xd7:num = 13; break;
                              case 0xb7:num = 14;break;
                              case 0x77:num = 15; break;
                     }

            while(temp != 0xf0)
            {
                     temp = P0;
                     temp = temp&0xf0;
            }
            }

}
            return num;
}

/*主函数*/
void main()
{
   uchar temp;
   init();                            //调用串口初始化函数
while(1)
{
i = keyscan1();          //调用矩阵键盘扫描函数
delay(200);                //进行延时
send(i);
}
}

/*更新寄存器的值*/
void  send (uchar  dat)
{
sbuf = dat;
  while(!TI);
TI = 0;
}

/*延时函数*/
void delay(uint z)
{
            uint i,j;
            for(i=z;i>0;i--)
            for(j=110;j>0;j--);
}

/*串口初始化函数*/
void init()
{
      TMOD = 0x20;                                        //定时器工作方式一
      SCON = 0x50;                                     //串口允许接收数据
      TH1 = 0xfd;
      TL1 = 0xfd;
      TR1 = 1;
}