数字钟

1．实验任务

（1．       开机时，显示12：00：00的时间开始计时；

（2．       P0.0/AD0控制“秒”的调整，每按一次加1秒；

（3．       P0.1/AD1控制“分”的调整，每按一次加1分；

（4．       P0.2/AD2控制“时”的调整，每按一次加1个小时；

2．电路原理图

图4.20.1

3．系统板上硬件连线

（1．       把“单片机系统”区域中的P1.0－P1.7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；

（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“动态数码显示”区域中的S1－S8端口上；

（3．       把“单片机系统”区域中的P0.0/AD0、P0.1/AD1、P0.2/AD2端口分别用导线连接到“独立式键盘”区域中的SP3、SP2、SP1端口上；

4．相关基本知识

（1．       动态数码显示的方法

（2．       独立式按键识别过程

（3．       “时”，“分”，“秒”数据送出显示处理方法

5．程序框图

6．汇编源程序

SECOND          EQU 30H

MINITE                     EQU 31H

HOUR            EQU 32H

HOURK          BIT P0.0

MINITEK         BIT P0.1

SECONDK        BIT P0.2

DISPBUF                    EQU 40H

DISPBIT            EQU 48H

T2SCNTA          EQU 49H

T2SCNTB         EQU 4AH

TEMP                      EQU 4BH

        ORG 00H

        LJMP START

        ORG 0BH

        LJMP INT_T0

START:  MOV SECOND,#00H

        MOV MINITE,#00H

        MOV HOUR,#12

        MOV DISPBIT,#00H

        MOV T2SCNTA,#00H

        MOV T2SCNTB,#00H

        MOV TEMP,#0FEH

        LCALL DISP

        MOV TMOD,#01H

        MOV TH0,#(65536-2000) / 256

        MOV TL0,#(65536-2000) MOD 256

        SETB TR0

        SETB ET0

        SETB EA

WT:     JB SECONDK,NK1

        LCALL DELY10MS

        JB SECONDK,NK1

        INC SECOND

        MOV A,SECOND

        CJNE A,#60,NS60

        MOV SECOND,#00H

NS60:   LCALL DISP

        JNB SECONDK,$

NK1:    JB MINITEK,NK2

        LCALL DELY10MS

        JB MINITEK,NK2

        INC MINITE

        MOV A,MINITE

        CJNE A,#60,NM60

        MOV MINITE,#00H

NM60:   LCALL DISP

        JNB MINITEK,$

NK2:    JB HOURK,NK3

        LCALL DELY10MS

        JB HOURK,NK3

        INC HOUR

        MOV A,HOUR

        CJNE A,#24,NH24

        MOV HOUR,#00H

NH24:   LCALL DISP

        JNB HOURK,$

NK3:    LJMP WT

DELY10MS:

        MOV R6,#10

D1:     MOV R7,#248

        DJNZ R7,$

        DJNZ R6,D1

        RET

DISP:  

        MOV A,#DISPBUF

        ADD A,#8

        DEC A

        MOV R1,A

        MOV A,HOUR

        MOV B,#10

        DIV AB

        MOV @R1,A

        DEC R1

        MOV A,B

        MOV @R1,A

        DEC R1

        MOV A,#10

        MOV@R1,A

        DEC R1

        MOV A,MINITE

        MOV B,#10

        DIV AB

        MOV @R1,A

        DEC R1

        MOV A,B

        MOV @R1,A

        DEC R1

        MOV A,#10

        MOV@R1,A

        DEC R1

        MOV A,SECOND

        MOV B,#10

        DIV AB

        MOV @R1,A

        DEC R1

        MOV A,B

        MOV @R1,A

        DEC R1

        RET

INT_T0:

        MOV TH0,#(65536-2000) / 256

        MOV TL0,#(65536-2000) MOD 256

        MOV A,#DISPBUF

        ADD A,DISPBIT

        MOV R0,A

        MOV A,@R0

        MOV DPTR,#TABLE

        MOVC A,@A+DPTR

        MOV P1,A

        MOV A,DISPBIT

        MOV DPTR,#TAB

        MOVC A,@A+DPTR

        MOV P3,A

        INC DISPBIT

        MOV A,DISPBIT

        CJNE A,#08H,KNA

        MOV DISPBIT,#00H

KNA:    INC T2SCNTA

        MOV A,T2SCNTA

        CJNE A,#100,DONE

        MOV T2SCNTA,#00H

        INC T2SCNTB

        MOV A,T2SCNTB

        CJNE A,#05H,DONE

        MOV T2SCNTB,#00H

        INC SECOND

        MOV A,SECOND

        CJNE A,#60,NEXT

        MOV SECOND,#00H

        INC MINITE

        MOV A,MINITE

        CJNE A,#60,NEXT

        MOV MINITE,#00H

        INC HOUR

        MOV A,HOUR

        CJNE A,#24,NEXT

        MOV HOUR,#00H

NEXT:   LCALL DISP

DONE:   RETI

TABLE:  DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH,40H

TAB:    DB 0FEH,0FDH,0FBH,0F7H,0EFH,0DFH,0BFH,07FH

        END

7．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 dispbitcode[]={0xfe,0xfd,0xfb,0xf7,

                             0xef,0xdf,0xbf,0x7f};

unsigned char dispbuf[8]={0,0,16,0,0,16,0,0};

unsigned char dispbitcnt;

unsigned char second;

unsigned char minite;

unsigned char hour;

unsigned int tcnt;

unsigned char mstcnt;

unsigned char i,j;

void main(void)

{

  TMOD=0x02;

  TH0=0x06;

  TL0=0x06;

  TR0=1;

  ET0=1;

  EA=1;

  while(1)

    {

      if(P0_0==0)

        {

          for(i=5;i>0;i--)

          for(j=248;j>0;j--);

          if(P0_0==0)

            {

              second++;

              if(second==60)

                {

                  second=0;

                }

              dispbuf[0]=second%10;

              dispbuf[1]=second/10;

              while(P0_0==0);

            }

        }

      if(P0_1==0)

        {

          for(i=5;i>0;i--)

          for(j=248;j>0;j--);

          if(P0_1==0)

            {

              minite++;

              if(minite==60)

                {

                  minite=0;

                }

              dispbuf[3]=minite%10;

              dispbuf[4]=minite/10;

              while(P0_1==0);

            }

        }

      if(P0_2==0)

        {

          for(i=5;i>0;i--)

          for(j=248;j>0;j--);

          if(P0_2==0)

            {

              hour++;

              if(hour==24)

                {

                  hour=0;

                }

              dispbuf[6]=hour%10;

              dispbuf[7]=hour/10;

              while(P0_2==0);

            }

        }

    }

}

void t0(void) interrupt 1 using 0

{

  mstcnt++;

  if(mstcnt==8)

    {

      mstcnt=0;

      P1=dispcode[dispbuf[dispbitcnt]];

      P3=dispbitcode[dispbitcnt];

      dispbitcnt++;

      if(dispbitcnt==8)

        {

          dispbitcnt=0;

        }

    }

  tcnt++;

  if(tcnt==4000)

    {

      tcnt=0;

      second++;

      if(second==60)

        {

          second=0;

          minite++;

          if(minite==60)

            {

              minite=0;

              hour++;

              if(hour==24)

                {

                  hour=0;

                }

            }

        }

      dispbuf[0]=second%10;

      dispbuf[1]=second/10;

      dispbuf[3]=minite%10;

      dispbuf[4]=minite/10;

      dispbuf[6]=hour%10;

      dispbuf[7]=hour/10;

    }

}