仿真原理图如下
 

单片机源程序如下：

#include

sbit wr=P3^6;

sbit rd=P3^2;

sbit key0=P1^0;

sbit key1=P1^1;

sbit key2=P1^2;

sbit key3=P1^3;

sbit key4=P1^4;

unsigned char flag;//flag为0、1、2、3、4时分别为正弦波、方波、三角波、梯形波、锯齿波

unsigned char const code ZXB_code[256]={

0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,

0xa5,0xa8,0xab,0xae,0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,

0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,0xda,0xdc,0xde,0xe0,

0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf4,

0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,

0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,

0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf3,0xf2,

0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe3,0xe1,0xde,0xdc,

0xda,0xd8,0xd6,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,

0xbc,0xb9,0xb6,0xb4,0xb1,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,

0x99,0x96,0x92,0x8f,0x8c,0x89,0x86,0x83,0x80,0x7d,0x79,0x76,

0x73,0x70,0x6d,0x6a,0x67,0x64,0x61,0x5e,0x5b,0x58,0x55,0x52,

0x4f,0x4c,0x49,0x46,0x43,0x41,0x3e,0x3b,0x39,0x36,0x33,0x31,

0x2e,0x2c,0x2a,0x27,0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,

0x15,0x14,0x12,0x10,0xf,0xd,0xc,0xb,0x9,0x8,0x7,0x6,0x5,0x4,

0x3,0x3,0x2,0x1,0x1,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,

0x0,0x1,0x1,0x2,0x3,0x3,0x4,0x5,0x6,0x7,0x8,0x9,0xa,0xc,0xd,

0xe,0x10,0x12,0x13,0x15,0x17,0x18,0x1a,0x1c,0x1e,0x20,0x23,

0x25,0x27,0x29,0x2c,0x2e,0x30,0x33,0x35,0x38,0x3b,0x3d,0x40,

0x43,0x46,0x48,0x4b,0x4e,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,

0x66,0x69,0x6c,0x6f,0x73,0x76,0x79,0x7c

};        //用于生成正弦

unsigned char keyscan()          //键盘扫描函数

{

  unsigned char keyscan_num,temp;

  P1=0xff;

  temp=P1;

  if(~(temp&0xff))

  {

    if(key0==0)

        {

          keyscan_num=1;

        }

        else if(key1==0)

        {

          keyscan_num=2;

        }

        else if(key2==0)

        {

          keyscan_num=3;

        }

        else if(key3==0)

        {

          keyscan_num=4;

        }

        else if(key4==0)

        {

          keyscan_num=5;

        }

        else

        {

          keyscan_num=0;

        }

        return keyscan_num;

  }

}

void init_DA0832()//DA芯片准备函数

{

  rd=0;

  wr=0;

}

void ZXB()//正弦波函数

{

  unsigned int i;

  do{

    P2=ZXB_code[i];

        i=i+1;

        }while(i<256);

}

void FB()//方波

{ 

  EA=1;

  ET0=1;

  TMOD=1;

  TR0=1;

  TH0=0xff;

  TL0=0x83;

}

void SJB()//三角波

{

  P2=0x00;

  do{

    P2=P2+1;

  }while(P2<0xff);

  P2=0xff;

  do{

    P2=P2-1;

  }while(P2>0x00);

  P2=0x00;

}

void JCB()//锯齿波

{

  P2=0x00;

  do{

    P2=P2+1;

  }while(P2<=0xff);

}

void TXB()//梯形波

{

  unsigned char i;

  P2=0x00;

  do{

    P2=P2+1;

  }while(P2<0xff);

  P2=0xff;

  for(i=255;i>0;i--)

  {

    P2=0xff;

  }

  do{

    P2=P2-1;

  }while(P2>0x00);

  P2=0x00;

}

void main()

{

  init_DA0832();

  do

    {

      flag=keyscan();

    }while(!flag);//等待按键按下

  while(1)

  {

    switch(flag)

    {

      case 1:

            do{

              flag=keyscan();

              ZXB();

             }while(flag==1);

            break;

          case 2:

            FB();

            do{

              flag=keyscan();

                  }while(flag==2);

                  TR0=0;

            break;

          case 3:

            do{

              flag=keyscan();

              SJB();

                  }while(flag==3);

            break;

          case 4:

            do{

              flag=keyscan();

              TXB();

                  }while(flag==4);

            break;

          case 5:

            do{

              flag=keyscan();

              JCB();

                  }while(flag==5);

            break;

          default:

            flag=keyscan();

            break;

    }        

  }

}

void timer0(void) interrupt 1

{

  P2=~P2;

  TH0=0xff;

  TL0=0x83;

  TR0=1;

}