电子琴

单片机系列实验
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1.实验任务
(1).由4X4组成16个按钮矩阵,设计成16个音。
(2).可随意弹奏想要表达的音乐。
2.电路原理图
电子琴

                                                                           图4.22.1
3.系统板硬件连线
(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;
4.相关程序内容
(1).4X4行列式键盘识别;
(2).音乐产生的方法;
一首音乐是许多不同的音阶组成的,而每个音阶对应着不同的频率,这样我们就可以利用不同的频率的组合,即可构成我们所想要的音乐了,当然对于单片机来产生不同的频率非常方便,我们可以利用单片机的定时/计数器T0来产生这样方波频率信号,因此,我们只要把一首歌曲的音阶对应频率关系弄正确即可。现在以单片机12MHZ晶振为例,例出高中低音符与单片机计数T0相关的计数值如下表所示

音符

频率(HZ

简谱码(T值)

 

音符

频率(HZ

简谱码(T值)

1 DO

262

63628

# 4 FA#

740

64860

#1 DO#

277

63731

5 SO

784

64898

2 RE

294

63835

# 5 SO#

831

64934

#2 RE#

311

63928

6 LA

880

64968

3 M

330

64021

# 6

932

64994

4 FA

349

64103

7 SI

988

65030

# 4 FA#

370

64185

1 DO

1046

65058

5 SO

392

64260

# 1 DO#

1109

65085

# 5 SO#

415

64331

2 RE

1175

65110

6 LA

440

64400

 

# 2 RE#

1245

65134

# 6

466

64463

3 M

1318

65157

7 SI

494

64524

4 FA

1397

65178

1 DO

523

64580

# 4 FA#

1480

65198

# 1 DO#

554

64633

5 SO

1568

65217

2 RE

587

64684

# 5 SO#

1661

65235

# 2 RE#

622

64732

6 LA

1760

65252

3 M

659

64777

# 6

1865

65268

4 FA

698

64820

7 SI

1967

65283

下面我们要为这个音符建立一个表格,有助于单片机通过查表的方式来获得相应的数据
低音0-19之间,中音在20-39之间,高音在40-59之间
TABLE:        DW 0,63628,63835,64021,64103,64260,64400,64524,0,0
                   DW 0,63731,63928,0,64185,64331,64463,0,0,0
                   DW 0,64580,64684,64777,64820,64898,64968,65030,0,0
                   DW 0,64633,64732,0,64860,64934,64994,0,0,0
                   DW 0,65058,65110,65157,65178,65217,65252,65283,0,0
                   DW 0,65085,65134,0,65198,65235,65268,0,0,0
                   DW 0
2、音乐的音拍,一个节拍为单位(C调)

曲调值

DELAY

 

曲调值

DELAY

4/4

125ms

 

4/4

62ms

3/4

187ms

 

3/4

94ms

2/4

250ms

 

2/4

125ms

对于不同的曲调我们也可以用单片机的另外一个定时/计数器来完成。
下面就用AT89S51单片机产生一首“生日快乐”歌曲来说明单片机如何产生的。
在这个程序中用到了两个定时/计数器来完成的。其中T0用来产生音符频率,T1用来产生音拍。
5.程序框图
电子琴
电子琴

                      图4.22.2
6.汇编源程序
KEYBUF      EQU 30H
STH0        EQU 31H
STL0        EQU 32H
TEMP        EQU 33H
            ORG 00H
            LJMP START
            ORG 0BH
            LJMP INT_T0
START:      MOV TMOD,#01H
            SETB ET0
            SETB EA
WAIT:  
            MOV P3,#0FFH
            CLR P3.4
            MOV A,P3
            ANL A,#0FH 
            XRL A,#0FH
            JZ NOKEY1
            LCALL DELY10MS
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY1
            MOV A,P3
            ANL A,#0FH
            CJNE A,#0EH,NK1
            MOV KEYBUF,#0
            LJMP DK1
NK1:        CJNE A,#0DH,NK2
            MOV KEYBUF,#1
            LJMP DK1
NK2:        CJNE A,#0BH,NK3
            MOV KEYBUF,#2
            LJMP DK1
1NK3:        CJNE A,#07H,NK4
            MOV KEYBUF,#3
            LJMP DK1
NK4:        NOP
DK1:   
            MOV A,KEYBUF
            MOV DPTR,#TABLE
            MOVC A,@A+DPTR
            MOV P0,A
            MOV A,KEYBUF
            MOV B,#2
            MUL AB
            MOV TEMP,A
            MOV DPTR,#TABLE1
            MOVC A,@A+DPTR
            MOV STH0,A
            MOV TH0,A
            INC TEMP
            MOV A,TEMP
            MOVC A,@A+DPTR
            MOV STL0,A
            MOV TL0,A
            SETB TR0
DK1A:       MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JNZ DK1A
            CLR TR0
NOKEY1:
            MOV P3,#0FFH
            CLR P3.5
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY2
            LCALL DELY10MS
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY2
            MOV A,P3
            ANL A,#0FH
            CJNE A,#0EH,NK5
            MOV KEYBUF,#4
            LJMP DK2
NK5:        CJNE A,#0DH,NK6
            MOV KEYBUF,#5
            LJMP DK2
NK6:        CJNE A,#0BH,NK7
            MOV KEYBUF,#6
            LJMP DK2
NK7:        CJNE A,#07H,NK8
            MOV KEYBUF,#7
            LJMP DK2
NK8:        NOP
DK2:   
            MOV A,KEYBUF
            MOV DPTR,#TABLE
            MOVC A,@A+DPTR
            MOV P0,A
            MOV A,KEYBUF
            MOV B,#2
            MUL AB
            MOV TEMP,A
            MOV DPTR,#TABLE1
            MOVC A,@A+DPTR
            MOV STH0,A
            MOV TH0,A
            INC TEMP
            MOV A,TEMP
            MOVC A,@A+DPTR
            MOV STL0,A
            MOV TL0,A
            SETB TR0
DK2A:       MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JNZ DK2A
            CLR TR0
NOKEY2:
            MOV P3,#0FFH
            CLR P3.6
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY3
            LCALL DELY10MS
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY3
            MOV A,P3
            ANL A,#0FH
            CJNE A,#0EH,NK9
            MOV KEYBUF,#8
            LJMP DK3
NK9:        CJNE A,#0DH,NK10
            MOV KEYBUF,#9
            LJMP DK3
NK10:       CJNE A,#0BH,NK11
            MOV KEYBUF,#10
            LJMP DK3
NK11:       CJNE A,#07H,NK12
            MOV KEYBUF,#11
            LJMP DK3
NK12:       NOP
DK3:
            MOV A,KEYBUF
            MOV DPTR,#TABLE
            MOVC A,@A+DPTR
            MOV P0,A
            MOV A,KEYBUF
            MOV B,#2
            MUL AB
            MOV TEMP,A
            MOV DPTR,#TABLE1
            MOVC A,@A+DPTR
            MOV STH0,A
            MOV TH0,A
            INC TEMP
            MOV A,TEMP
            MOVC A,@A+DPTR
            MOV STL0,A
            MOV TL0,A
            SETB TR0
DK3A:       MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JNZ DK3A
            CLR TR0
NOKEY3:
            MOV P3,#0FFH
            CLR P3.7
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY4
            LCALL DELY10MS
            MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JZ NOKEY4
            MOV A,P3
            ANL A,#0FH
            CJNE A,#0EH,NK13
            MOV KEYBUF,#12
            LJMP DK4
NK13:       CJNE A,#0DH,NK14
            MOV KEYBUF,#13
            LJMP DK4
NK14:       CJNE A,#0BH,NK15
            MOV KEYBUF,#14
            LJMP DK4
NK15:       CJNE A,#07H,NK16
            MOV KEYBUF,#15
            LJMP DK4
NK16:       NOP
DK4:   
            MOV A,KEYBUF
            MOV DPTR,#TABLE
            MOVC A,@A+DPTR
            MOV P0,A
            MOV A,KEYBUF
            MOV B,#2
            MUL AB
            MOV TEMP,A
            MOV DPTR,#TABLE1
            MOVC A,@A+DPTR
            MOV STH0,A
            MOV TH0,A
            INC TEMP
            MOV A,TEMP
            MOVC A,@A+DPTR
            MOV STL0,A
            MOV TL0,A
            SETB TR0
DK4A:       MOV A,P3
            ANL A,#0FH
            XRL A,#0FH
            JNZ DK4A
            CLR TR0
NOKEY4:
            LJMP WAIT
DELY10MS:
            MOV R6,#10
D1:         MOV R7,#248
            DJNZ R7,$
            DJNZ R6,D1
            RET
INT_T0:
            MOV TH0,STH0
            MOV TL0,STL0
            CPL P1.0
            RETI
TABLE:      DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H
            DB 7FH,6FH,77H,7CH,39H,5EH,79H,71H
TABLE1:     DW 64021,64103,64260,64400
            DW 64524,64580,64684,64777
            DW 64820,64898,64968,65030
            DW 65058,65110,65157,65178
            END
7.C语言源程序
#include
unsigned char code table[]={0x3f,0x06,0x5b,0x4f,
                            0x66,0x6d,0x7d,0x07,
                            0x7f,0x6f,0x77,0x7c,
                            0x39,0x5e,0x79,0x71};
unsigned char temp;
unsigned char key;
unsigned char i,j;
unsigned char STH0;
unsigned char STL0;
unsigned int code tab[]={64021,64103,64260,64400,
                          64524,64580,64684,64777,
                          64820,64898,64968,65030,
                          65058,65110,65157,65178};
void main(void)
{
  TMOD=0x01;
  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=0;
                    break;
                  case 0x0d:
                    key=1;
                    break;
                  case 0x0b:
                    key=2;
                    break;
                  case 0x07:
                    key=3;
                    break;
                }
              temp=P3;
              P1_0=~P1_0;
              P0=table[key];
              STH0=tab[key]/256;
              STL0=tab[key]%6;
              TR0=1;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              TR0=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=7;
                    break;
                }
              temp=P3;
              P1_0=~P1_0;
              P0=table[key];
              STH0=tab[key]/256;
              STL0=tab[key]%6;
              TR0=1;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              TR0=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=8;
                    break;
                  case 0x0d:
                    key=9;
                    break;
                  case 0x0b:
                    key=10;
                    break;
                  case 0x07:
                    key=11;
                    break;
                }
              temp=P3;
              P1_0=~P1_0;
              P0=table[key];
              STH0=tab[key]/256;
              STL0=tab[key]%6;
              TR0=1;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              TR0=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=12;
                    break;
                  case 0x0d:
                    key=13;
                    break;
                  case 0x0b:
                    key=14;
                    break;
                  case 0x07:
                    key=15;
                    break;
                }
              temp=P3;
              P1_0=~P1_0;
              P0=table[key];
              STH0=tab[key]/256;
              STL0=tab[key]%6;
              TR0=1;
              temp=temp & 0x0f;             
              while(temp!=0x0f)
                {
                  temp=P3;
                  temp=temp & 0x0f;             
                }
              TR0=0;
            }
        }     
    }
}
void t0(void) interrupt 1 using 0
{
  TH0=STH0;
  TL0=STL0;
  P1_0=~P1_0;
}

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