1．实验任务
（1）.开机时，显示“0”
（2）.第一次按下时，显示“D1”；第二次按下时，显示“D1D2”；第三按下时，显示“D1D2D3”，8个全显示完毕，再按下按键下时，给出“嘀”提示音。
2．电路原理图

图4.23.1
3．系统板上硬件连线
（1）.把“单片机系统”区域中的P1.0端口用导线连接到“音频放大模块”区域中的SPK IN端口上；
（2）.把“单片机系统“区域中的P3.0－P3.7端口用8芯排线连接到“4X4行列式键盘”区域中的C1－C4　R1－R4端口上；
（3）.把“单片机系统”区域中的P0.0－P0.7端口用8芯排线连接到“动态数码显示”区域中的A－H端口上；
（4）.把“单片机系统：区域中的P2.0－P2.7端口用8芯排线连接到“动态数码显示”区域中的S1－S8端口上；
4．相关程序设计内容
（1）.行列式键盘输入及按键功能设定；
（2）.动态数码显示；
（3）.数码显示方式处理；
5．汇编源程序
（略）
6．C语言源程序
#include
unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71,0x00};
unsigned char code dispbitcode[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};
unsigned char dispbuf[8]={0,16,16,16,16,16,16,16};
unsigned char dispbitcount;
unsigned char temp;
unsigned char i,j;
unsigned char key;
unsigned char keypos;
bit alarmflag;
void change(unsigned char *p,unsigned char count)
{
  while(count>0)
    {
      *(p+count)=*(p+count-1);
      count--;
    }
}
void main(void)
{
  TMOD=0x01;
  TH0=(65536-4000) / 256;
  TL0=(65536-4000) % 256;
  TR0=1;
  ET0=1;
  EA=1;
  while(1)
    {
      P3=0xff;
      P3_4=0;
      temp=P3;
      temp=temp & 0x0f;
      if (temp!=0x0f)
        {
          for(i=50;i>0;i--)
          for(j=200;j>0;j--);
          temp=P3;
          temp=temp & 0x0f;
          if (temp!=0x0f)
            {
              temp=P3;
              temp=temp & 0x0f;             
              switch(temp)
                {
                  case 0x0e:
                    key=7;
                    break;
                  case 0x0d:
                    key=8;
                    break;
                  case 0x0b:
                    key=9;
                    break;
                  case 0x07:
                    key=10;
                    break;
                }
              if ((key>=0) && (key<10))
              {
                keypos++;
                if(keypos<8)
                  {
                    change(dispbuf,keypos);
                    dispbuf[0]=key;
                  }
                  else
                    {
                      keypos=8;
                      alarmflag=1;
                    }
              }
              temp=P3;
              P1_0=~P1_0;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              alarmflag=0;
            }
        }
      P3=0xff;
      P3_5=0;
      temp=P3;
      temp=temp & 0x0f;
      if (temp!=0x0f)
        {
          for(i=50;i>0;i--)
          for(j=200;j>0;j--);
          temp=P3;
          temp=temp & 0x0f;
          if (temp!=0x0f)
            {
              temp=P3;
              temp=temp & 0x0f;             
              switch(temp)
                {
                  case 0x0e:
                    key=4;
                    break;
                  case 0x0d:
                    key=5;
                    break;
                  case 0x0b:
                    key=6;
                    break;
                  case 0x07:
                    key=11;
                    break;
                }
              if ((key>=0) && (key<10))
              {
                keypos++;
                if(keypos<8)
                  {
                    change(dispbuf,keypos);
                    dispbuf[0]=key;
                  }
                  else
                    {
                      keypos=8;
                      alarmflag=1;
                    }
              }
              temp=P3;
              P1_0=~P1_0;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              alarmflag=0;
            }
        }
      P3=0xff;
      P3_6=0;
      temp=P3;
      temp=temp & 0x0f;
      if (temp!=0x0f)
        {
          for(i=50;i>0;i--)
          for(j=200;j>0;j--);
          temp=P3;
          temp=temp & 0x0f;
          if (temp!=0x0f)
            {
              temp=P3;
              temp=temp & 0x0f;             
              switch(temp)
                {
                  case 0x0e:
                    key=1;
                    break;
                  case 0x0d:
                    key=2;
                    break;
                  case 0x0b:
                    key=3;
                    break;
                  case 0x07:
                    key=12;
                    break;
                }
              if ((key>=0) && (key<10))
              {
                keypos++;
                if(keypos<8)
                  {
                    change(dispbuf,keypos);
                    dispbuf[0]=key;
                  }
                  else
                    {
                      keypos=8;
                      alarmflag=1;
                    }
              }
              temp=P3;
              P1_0=~P1_0;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;              
                }
              alarmflag=0;
            }
        }
      P3=0xff;
      P3_7=0;
      temp=P3;
      temp=temp & 0x0f;
      if (temp!=0x0f)
        {
          for(i=50;i>0;i--)
          for(j=200;j>0;j--);
          temp=P3;
          temp=temp & 0x0f;
          if (temp!=0x0f)
            {
              temp=P3;
              temp=temp & 0x0f;             
              switch(temp)
                {
                  case 0x0e:
                    key=0;
                    break;
                  case 0x0d:
                    key=13;
                    break;
                  case 0x0b:
                    key=14;
                    break;
                  case 0x07:
                    key=15;
                    break;
                }
              if ((key>=0) && (key<10))
              {
                keypos++;
                if(keypos<8)
                  {
                    change(dispbuf,keypos);
                    dispbuf[0]=key;
                  }
                  else
                    {
                      keypos=8;
                      alarmflag=1;
                    }
              }
              temp=P3;
              P1_0=~P1_0;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              alarmflag=0;
            }
        }

    }
}
void t0(void) interrupt 1 using 0
{
  TH0=(65536-4000) / 256;
  TL0=(65536-4000) % 256;
  P0=dispcode[dispbuf[dispbitcount]];
  P2=dispbitcode[dispbitcount];
  dispbitcount++;
  if (dispbitcount==8)
    {
      dispbitcount=0;
    }
  if (alarmflag==1)
    {
      P1_1=~P1_1;
    }
}