1．  实验任务

在8X8点阵式LED显示“★”、“●”和心形图，通过按键来选择要显示的图形。

2． 电路原理图

图4.26.1

3． 硬件系统连线

(1)．  把“单片机系统”区域中的P1端口用8芯排芯连接到“点阵模块”区域中的“DR1－DR8”端口上；

(2)．  把“单片机系统”区域中的P3端口用8芯排芯连接到“点阵模块”区域中的“DC1－DC8”端口上；

(3)．  把“单片机系统”区域中的P2.0/A8端子用导线连接到“独立式键盘”区域中的SP1端子上；

4． 程序设计内容

(1)．  “★”在8X8LED点阵上显示图如下图所示

1　2　3   4　5　 6  7  8

12H，14H，3CH，48H，3CH，14H，12H，00H

(2)．  “●”在8X8LED点阵上显示图如下图所示

1　2　3   4　5　 6  7  8

00H，00H，38H，44H，44H，44H，38H，00H

(3)．  心形图在8X8LED点阵上显示图如下图所示

1　2　3   4　5　 6  7  8

30H，48H，44H，22H，44H，48H，30H，00H

5． 汇编源程序

CNTA        EQU 30H

COUNT    EQU 31H

                   ORG 00H

                   LJMP START

                   ORG 0BH

                   LJMP T0X

                   ORG 30H

START:      MOV CNTA,#00H

                   MOV COUNT,#00H

                   MOV TMOD,#01H

                   MOV TH0,#(65536-4000) / 256

                   MOV TL0,#(65536-4000) MOD 256

                   SETB TR0

                   SETB ET0

                   SETB EA

WT:            JB P2.0,WT

                   MOV R6,#5

                   MOV R7,#248

D1:             DJNZ R7,$

                   DJNZ R6,D1

                   JB P2.0,WT

                   INC COUNT

                   MOV A,COUNT

                   CJNE A,#03H,NEXT

                   MOV COUNT,#00H

NEXT:       JNB P2.0,$

                   SJMP WT

T0X: NOP

                   MOV TH0,#(65536-4000) / 256

                   MOV TL0,#(65536-4000) MOD 256

                   MOV DPTR,#TAB

                   MOV A,CNTA

                   MOVC A,@A+DPTR

                   MOV P3,A

                   MOV DPTR,#GRAPH

                   MOV A,COUNT

                   MOV B,#8

                   MUL AB

                   ADD A,CNTA

                   MOVC A,@A+DPTR

                   MOV P1,A

                   INC CNTA

                   MOV A,CNTA

                   CJNE A,#8,NEX

                   MOV CNTA,#00H

NEX:         RETI

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

GRAPH:    DB 12H,14H,3CH,48H,3CH,14H,12H,00H

                   DB 00H,00H,38H,44H,44H,44H,38H,00H

                   DB 30H,48H,44H,22H,44H,48H,30H,00H

                   END

6． C语言源程序

#include <AT89X52.H>

unsigned char code tab[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};

unsigned char code graph[3][8]={{0x12,0x14,0x3c,0x48,0x3c,0x14,0x12,0x00},

                                {0x00,0x00,0x38,0x44,0x44,0x44,0x38,0x00},

                                {0x30,0x48,0x44,0x22,0x44,0x48,0x30,0x00}

                               };

unsigned char count;

unsigned char cnta;

void main(void)

{

  unsigned char i,j;

  TMOD=0x01;

  TH0=(65536-4000)/256;

  TL0=(65536-4000)%256;

  TR0=1;

  ET0=1;

  EA=1;

  while(1)

    {

      if(P2_0==0)

        {

          for(i=5;i>0;i--)

          for(j=248;j>0;j--);

          if(P2_0==0)

            {

              count++;

              if(count==3)

                {

                  count=0;

                }

              while(P2_0==0);

            }

        }

    }

}

void t0(void) interrupt 1 using 0

{

  TH0=(65536-4000)/256;

  TL0=(65536-4000)%256;

  P3=tab[cnta];

  P1=graph[count][cnta];

  cnta++;

  if(cnta==8)

    {

      cnta=0;

    }

}