電路圖如上圖所示,此接法是用DAC0832的直通方式,只要二進(jìn)制數(shù)據(jù)送到DAC0832的數(shù)據(jù)口,則會自動把數(shù)據(jù)轉(zhuǎn)為相應(yīng)的電壓.但運放是如圖的電壓則輸出一般不可能達(dá)到基準(zhǔn)電壓.要想達(dá)到基準(zhǔn)電壓則要提高運放的電壓.當(dāng)基準(zhǔn)為負(fù)是,只要提高運放的正電壓就可以使輸出達(dá)到基準(zhǔn)電壓了,當(dāng)基準(zhǔn)為正是,則為提高運放的負(fù)電壓,一般的運放提高兩伏就可以了,但不同的運放會有些區(qū)別.

程序如下:

1.輸出固定電壓的程序

#include "reg51.h"
void DAC0832(unsigned char x)
{
  P2=x;
}
void main()
{
  DAC0832(255);
  while(1){
  ;}
}

2.輸出三角波與正弦波程序．

#include<AT89X52.H>
unsigned char flag;   //波型輸出標(biāo)置變量
bit time;            
unsigned char sin(unsigned char x)
{
unsigned char code sin_tab[]={125,128,131,134,138,141,144,147,150,153,156,159,
         162,165,168,171,174,177,180,182,185,188,191,193,196,198,201,203,
   206,208,211,213,215,217,219,221,223,225,227,229,231,232,234,235,
   237,238,239,241,242,243,244,245,246,246,247,248,248,249,249,250,
   250,250,250,250,250,250,250,249,249,248,248,247,246,246,245,244,
   243,242,241,239,238,237,235,234,232,231,229,227,225,223,221,219,
   217,215,213,211,208,206,203,201,198,196,193,191,188,185,182,180,
   177,174,171,168,165,162,159,156,153,150,147,144,141,138,134,131,
   128,125,122,119,116,112,109,106,103,100,97,94,91,88,85,82,79,76,73,
   70,68,65,62,59,57,54,52,49,47,44,42,39,37,35,33,31,29,27,25,27,29,27,25,23,21,
   19,18,16,15,13,12,11,9,8,7,6,5,4,4,3,2,2,1,1,0,0,0,0,0,0,0,0,1,1,2,
   2,3,4,4,5,6,7,8,9,11,12,13,15,16,18,19,21,23,25,27,29,31,33,35,37,
   39,42,44,47,49,52,54,57,59,62,65,68,70,73,76,79,82,85,88,97,94,97,
   100,103,106,109,112,116,119,122};
   return sin_tab[x];
   }
void DAC0832(unsigned char x)
{
  P2=x;
}
void main()
{
unsigned char i;
TMOD=0X02;        //定時器0用于控制輸出波的頻率
TH0=256-40;
ET0=1;     //按鍵接于外部中斷0，與中斷1
IT0=1;
IT1=1;
EX0=1;
EX1=1;
EA=1;
TR0=1;
flag=0;     //開始時無輸出
i=0;
 while(1)
   {
      if(time==1)
     {
       time="0";
    if(i>249)
       i="0";
    else
       i++;
   switch(flag)     //當(dāng)按鍵1的為輸出三角波，按鍵2時輸出正弦波
     {
        case 0:DAC0832(0);break;
     case 1:
             if(i>125)
         DAC0832(250-i);
       else
         DAC0832(i);
         break;
    case 2:
             DAC0832(sin(i));
       break;
    default:  break;
     }
      }
    }
}
void time0() interrupt 1
{
  time="1";
}
 
 void int0() interrupt 0
 {         //按鍵1接于外部中斷0
    flag="1";
}
 
  void int1() interrupt 2     //按鍵2接于外部中斷1
  {
    flag="2";
}