相信很多朋友都可能接觸到一個波型發生器的制作，可能剛剛入門，做的東西也不會說是很復雜。可能就一個矩形波，或者是三角波。但是網上的很多資料是忽悠人的，就此，我也提供一個比較完整的波型發生器 C51 原代：

       該系統的軟件比較典型：包括鍵盤的應用，顯示的應用和 DA 轉換器的應用。本設計中，輸出的波形有三種：正弦波，方波，三角波。

       方波的輸出最為簡單，只要按照設定的周期值將輸出的電壓改變即可。

       三角波的輸出也比較簡單，單片機的輸出只要完成數字量遞增和遞減交替進行即可。、

      正弦波的輸出最麻煩，如果在軟件中計算出輸出的各點電壓值，將會浪費很多的 CPU 時間，以至于無法滿足頻率的要求。通常最簡單的方法是通過手動的方法計算出輸出各點的電壓值，然后在編寫程序時以數組的方式給出。當需要時，只要按照順序進行輸出即可。這種方法比運算法速度快且曲線的形狀修改靈活。在本設計中將 360 度分為 256 個點，則每兩個點之間的間隔為 1.4 度，然后計算出每個點電壓對應的數字量即可。只要反復輸出這組數據到 DAC0832, 就可以在系統輸出端得到想要的正弦波。

具體程序如下：

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
#define DAdata P0
uchar code Sinetab[256]=
{
0x80,0x82,0x84,0x86,0x88,0x8a,0x8c,0x8e,
0x90,0x92,0x94,0x96,0x98,0x9a,0x9c,0x9e,
0xa0,0xa2,0xa4,0xa6,0xa8,0xaa,0xab,0xad,
0xaf,0xb1,0xb2,0xb4,0xb6,0xb7,0xb9,0xba,
0xbc,0xbd,0xbf,0xc0,0xc1,0xc3,0xc4,0xc5,
0xc6,0xc8,0xc9,0xca,0xcb,0xcc,0xcd,0xce,
0xce,0xcf,0xd0,0xd1,0xd1,0xd2,0xd2,0xd3,
0xd3,0xd3,0xd2,0xd2,0xd1,0xd1,0xd0,0xcf,
0xce,0xce,0xcd,0xcc,0xcb,0xca,0xc9,0xc8,
0xc6,0xc5,0xc4,0xc3,0xc1,0xc0,0xbf,0xbd,
0xbc,0xba,0xb9,0xb7,0xb6,0xb4,0xb2,0xb1,
0xaf,0xad,0xab,0xaa,0xa8,0xa6,0xa4,0xa2,
0xa0,0x9e,0x9c,0x9a,0x98,0x96,0x94,0x92,
0x90,0x8e,0x8c,0x8a,0x88,0x86,0x84,0x82,
0x80,0x7d,0x7b,0x79,0x77,0x75,0x73,0x71,
0x6f,0x6d,0x6b,0x69,0x67,0x65,0x63,0x61,
0x5f,0x5d,0x5b,0x59,0x57,0x55,0x54,0x52,
0x50,0x4e,0x4d,0x4b,0x49,0x48,0x46,0x45,
0x43,0x42,0x40,0x3f,0x3e,0x3c,0x3b,0x3a,
0x39,0x37,0x36,0x35,0x34,0x33,0x32,0x31,
0x31,0x30,0x2f,0x2e,0x2e,0x2d,0x2d,0x2c,
0x2c,0x2b,0x2b,0x2b,0x2b,0x2a,0x2a,0x2a,
0x2a,0x2a,0x2a,0x2a,0x2b,0x2b,0x2b,0x2b,
0x2c,0x2c,0x2d,0x2d,0x2e,0x2e,0x2f,0x30,
0x31,0x31,0x32,0x33,0x34,0x35,0x36,0x37,
0x39,0x3a,0x3b,0x3c,0x3e,0x3f,0x40,0x42,
0x43,0x45,0x46,0x48,0x49,0x4b,0x4d,0x4e,
0x50,0x52,0x54,0x55,0x57,0x59,0x5b,0x5d,
0x5f,0x61,0x63,0x65,0x67,0x69,0x6b,0x6d,
0x6f,0x71,0x73,0x75,0x77,0x79,0x7b,0x7d,
};

uchar code Triangletab[58]=
{
0x1a,0x21,0x28,0x2f,0x36,0x3d,0x44,0x4b,
0x52,0x59,0x60,0x67,0x6e,0x75,0x7c,0x83,
0x8a,0x91,0x98,0x9f,0xa6,0xad,0xb4,0xbb,
0xc2,0xc9,0xd0,0xd7,0xde,0xe5,
0xde,0xd7,0xd0,0xc9,0xc2,0xbb,0xb4,0xad,
0xa6,0x9f,0x98,0x91,0x8a,0x83,0x7c,0x75,
0x6e,0x67,0x60,0x59,0x52,0x4b,0x44,0x3d,
0x36,0x2f,0x28,0x21,
};

uchar code Squaretab[2]={0x56,0xaa};

uchar code disp1[]=
{
"Sine Wave       "
"Triangle Wale   "
"Square Wave     "
};

uchar idata disp2[16]={"Frequency:    Hz"};

uchar code Coef[3]={10,100,200};

uchar idata WaveFre[3]={1,1,1};

uchar code WaveTH[]=
{
0xfc,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xfc,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,

};

uchar code WaveTL[]=
{
0xf2,0x78,0xfb,0x3c,0x63,0x7d,0x8f,0x9d,0xa8,0xb1,
0x17,0x0b,0xb2,0x05,0x37,0x58,0x70,0x82,0x90,0x9b,
0x4d,0xa7,0xc4,0xd3,0xdc,0xe2,0xe6,0xea,0xec,0xee
};

uchar Wavecount,THtemp,TLtemp;
uchar Waveform;
sbit rs=P2^5;
sbit rw=P2^6;
sbit e=P2^7;
sbit DA=P2^0;
sbit KEY=P3^2;
void delay(uchar i)
{
uchar j;
for(;i>0;i--)
   for(j=20;j>0;j--);
}

void busy()
{
uchar temp;
temp=0x00;
rs=0;
rw=1;
while((temp&0x80)==0x80)
   {
    P0=0xff;
    e=1;
    temp=P0;
    e=0;
   }
}

void WR_Com(uchar temp)
{
busy();
rs=0;
rw=0;
P0=temp;
e=1;
e=0;
}

void WR_Data(uchar num)
{
busy();
rs=1;
rw=0;
P0=num;
e=1;
e=0;
}

void disp_lcd(uchar addr,uchar *temp1)
{
uchar i;
WR_Com(addr);
delay(100);
for(i=0;i<16;i++)
   {
    WR_Data(temp1[i]);
    delay(100);
   }
}

void lcd_ini()
{
char i;
for(i=3;i>0;i--)
   {
    P0=0x30;
    rs=0;
    rw=0;
    e=1;
    e=0;
    delay(100);
   }
P0=0x38;
rs=0;
rw=0;
e=1;
e=0;
delay(100);
}

void lcd_Reset()
{
WR_Com(0x01);
delay(100);
WR_Com(0x06);
delay(100);
WR_Com(0x0c);
delay(100);
}

void SineOUT(uchar Wavecount)
{
DAdata=Sinetab[Wavecount++];
Wavecount=0;
DA=0;
DA=1;
}

void TriangleOUT(uchar Wavecount)
{
DAdata=Triangletab[Wavecount++];
if(Wavecount>57)
   Wavecount=0;
DA=0;
DA=1;
}

void SquareOUT(uchar Wavecount)
{
DAdata=Squaretab[Wavecount++];
if(Wavecount>1)
Wavecount=0;
DA=0;
DA=1;
}

void timer() interrupt 1
{
TH0=THtemp;
TL0=THtemp;
if(Waveform==0)
   SineOUT(Wavecount);
else if(Waveform==1)
   TriangleOUT(Wavecount);
else if(Waveform==2)
   SquareOUT(Wavecount);
}

void key_int() interrupt 0
{
uchar keytemp,keytemp1;
uint WaveCoef;
EA=0;
TR0=0;
keytemp1=0;
delay(10);
while(!KEY);
keytemp=~P2&0x1e;
keytemp>>=1;
while(keytemp!=8)
   {
    keytemp=~P2&0x1e;
    keytemp>>=1;
    if(keytemp!=keytemp1)
     {
      keytemp1=keytemp;
      switch(keytemp)
       {
        case 1:
         if(++Waveform==3)
          Waveform=0;
         break;
        case 2:
         if(++WaveFre[Waveform]==11)
          WaveFre[Waveform]=1;
         break;
        case 4:
         if(--WaveFre[Waveform]==0)
          WaveFre[Waveform]=10;
         break;
       }
    THtemp=WaveTH[Waveform*16+(WaveFre[Waveform]-1)];
    TLtemp=WaveTL[Waveform*16+(WaveFre[Waveform]-1)];
    WaveCoef=WaveFre[Waveform]*Coef[Waveform];
    disp2[13]=WaveCoef%10+0x30;
    WaveCoef/=10;
    disp2[12]=WaveCoef%10+0x30;
    WaveCoef/=10;
    disp2[11]=WaveCoef%10+0x30;
    WaveCoef/=10;
    disp2[10]=WaveCoef%10+0x30;
    WaveCoef/=10;
    disp_lcd(0x80,&disp1[Waveform*16]);
    disp_lcd(0xc0,disp2);
     }
   }
   TH0=THtemp;
   TL0=THtemp;
   Wavecount=0;
   TR0=1;
}

void main()
{
uint WaveCoef;
uchar i;
lcd_ini();
lcd_Reset();
WaveCoef=WaveFre[Waveform]*Coef[Waveform];
disp2[13]=WaveCoef%10+0x30;
WaveCoef/=10;
disp2[12]=WaveCoef%10+0x30;
WaveCoef/=10;
disp2[11]=WaveCoef%10+0x30;
WaveCoef/=10;
disp2[10]=WaveCoef%10+0x30;
WaveCoef/=10;
disp_lcd(0x80,&disp1[Waveform*16]);
disp_lcd(0xc0,disp2);
i=0;
DAdata=0x00;
DA=0;
TMOD=0x01;
IT0=1;
ET0=1;
EX0=1;
EA=1;
while(1);
}