求解!!!基于adc0809的電壓表所測電壓與實際電壓相差過大

ID:202266 · 發(fā)表于 2017-5-18 17:49

電路連接沒有問題，就是測的電壓與實際電壓差太多了，求高手指教��！是不是程序有問題
（VREF+)=5V；
（VREF-)=0V;

這是程序

/*--------------------------------------------------------------
   adc0809數(shù)字電壓表
--------------------------------------------------------------*/
#include<reg52.h> //包含頭文件，一般情況不需要改動，頭文件包含特殊功能寄存器的定義
#include<intrins.h>

sbit RS = P1^0; //定義端口
sbit RW = P1^1;
sbit EN = P1^2;
sbit DU = P2^6;
sbit WE = P2^7;
sbit CLK=P2^0;
sbit ST=P2^3;
sbit ALE=P2^7;
sbit OE=P2^5;
sbit EOC=P2^4;
sbit ADDA=P1^5;
sbit ADDB=P1^6;
sbit ADDC=P1^7;
unsigned char AD_DATA[1];
unsigned int h_date;
void keyscan();

#define RS_CLR RS=0
#define RS_SET RS=1

#define RW_CLR RW=0
#define RW_SET RW=1

#define EN_CLR EN=0
#define EN_SET EN=1

#define DataPort P0

void cmg88()//關(guān)數(shù)碼管，點陣函數(shù)
{
DU=1;
P0=0X00;
DU=0;
}
/*------------------------------------------------
uS延時函數(shù)，含有輸入?yún)?shù) unsigned char t，無返回值
unsigned char 是定義無符號字符變量，其值的范圍是
0~255 這里使用晶振12M，精確延時請使用匯編,大致延時
長度如下 T=tx2+5 uS
------------------------------------------------*/
void DelayUs2x(unsigned char t)
{
while(--t);
}
/*------------------------------------------------
         延時函數(shù)
------------------------------------------------*/
void DelayMs(unsigned char t)
{

while(t--)
{
   //大致延時1mS
   DelayUs2x(245);
   DelayUs2x(245);
}
}
/*------------------------------------------------
            判忙函數(shù)
------------------------------------------------*/
bit LCD_Check_Busy(void)
{
DataPort= 0xFF;
RS_CLR;
RW_SET;
EN_CLR;
_nop_();
EN_SET;
return (bit)(DataPort & 0x80);
}
/*------------------------------------------------
            寫入命令函數(shù)
------------------------------------------------*/
void LCD_Write_Com(unsigned char com)
{
while(LCD_Check_Busy()); //忙則等待
RS_CLR;
RW_CLR;
EN_SET;
DataPort= com;
_nop_();
EN_CLR;
}
/*------------------------------------------------
            寫入數(shù)據(jù)函數(shù)
------------------------------------------------*/
void LCD_Write_Data(unsigned char Data)
{
while(LCD_Check_Busy()); //忙等待
RS_SET;
RW_CLR;
EN_SET;
DataPort= Data;
_nop_();
EN_CLR;
}

/*------------------------------------------------
            清屏函數(shù)
------------------------------------------------*/
void LCD_Clear(void)
{
LCD_Write_Com(0x01);
DelayMs(5);
}
/*------------------------------------------------
            寫入字符串函數(shù)
------------------------------------------------*/
void LCD_Write_String(unsigned char x,unsigned char y,unsigned char *s)
{
if (y == 0)
{
   LCD_Write_Com(0x80 + x);    //表示第一行
}
else
{
LCD_Write_Com(0xC0 + x);    //表示第二行
}
while (*s)
{
LCD_Write_Data( *s);
s ++;
}
}
/*------------------------------------------------
            寫入字符函數(shù)
------------------------------------------------*/
void LCD_Write_Char(unsigned char x,unsigned char y,unsigned char Data)
{
if (y == 0)
{
LCD_Write_Com(0x80 + x);
}
else
{
LCD_Write_Com(0xC0 + x);
}
LCD_Write_Data( Data);
}
/*------------------------------------------------
            初始化函數(shù)
------------------------------------------------*/
void LCD_Init(void)
{
LCD_Write_Com(0x38); /*顯示模式設(shè)置*/
DelayMs(5);
LCD_Write_Com(0x38);
DelayMs(5);
LCD_Write_Com(0x38);
DelayMs(5);
LCD_Write_Com(0x38);
LCD_Write_Com(0x08); /*顯示關(guān)閉*/
LCD_Write_Com(0x01); /*顯示清屏*/
LCD_Write_Com(0x06); /*顯示光標(biāo)移動設(shè)置*/
DelayMs(5);
LCD_Write_Com(0x0C); /*顯示開及光標(biāo)設(shè)置*/
}
/*------------------------------------------------
                  adc0809初始化函數(shù)
------------------------------------------------*/
void ADC0809_init() //ADC0809初始化
{
TMOD=0x01;
TH0=(65536-200)/256;
TL0=(65536-200)%256;
ET0=1;
TR0=1;
EA=1;
DelayMs(2);
}

/*------------------------------------------------
                  adc讀數(shù)據(jù)
------------------------------------------------*/

unsigned char  Read_AD()  //讀ADC0809數(shù)據(jù)
{
unsigned char temp=0; //存放AD采集的數(shù)據(jù)
while(EOC==0); //等待轉(zhuǎn)換完成
        OE=1;
   temp=P3;    //讀取數(shù)據(jù)
   DelayMs(1);
   OE=0;
   return temp;
}
/*------------------------------------------------
                  500KHz時鐘頻率
------------------------------------------------*/

void timer0(void) interrupt 1 //中斷處理函數(shù)，產(chǎn)生約500KHz時鐘供0809工作
{
TH0=(65536-200)/256;
TL0=(65536-200)%256;
CLK=~CLK;
}

/*------------------------------------------------
                  通道選擇
------------------------------------------------*/

void keyscan()
{
ALE=1;  //允許寫入地址
ADDA=0;
ADDB=0;
ADDC=0;
ALE=0;

}

/*------------------------------------------------
                  主函數(shù)
------------------------------------------------*/
void main(void)
{
cmg88();//關(guān)數(shù)碼管，點陣函數(shù)
LCD_Init();
LCD_Clear();//清屏
ADC0809_init();
LCD_Write_String(1,0, "AD_Change_V");//在液晶的第一行顯示字符
while (1)
{
  ST=0 ;
  keyscan();
  ST=1;
  ST=0;
  //keyscan();
  Read_AD();
  AD_DATA[0]=Read_AD();
  h_date=AD_DATA[0]*100;
  // LCD_Write_Char(13,0, h_date);
  LCD_Write_String(0,1, "AD="); //在液晶的第二行第0位開始顯示"AD="
  LCD_Write_Char( 3, 1, AD_DATA[0]/100+0x30); //顯示AD數(shù)據(jù)的百位
  LCD_Write_Char( 4, 1, AD_DATA[0]/10%10+0x30);//顯示AD數(shù)據(jù)的十位
  LCD_Write_Char( 5, 1, AD_DATA[0]%10+0x30);//顯示AD數(shù)據(jù)的各位
  LCD_Write_String(7,1, "Vin="); //在液晶的第二行第8位開始顯示"Vin="
  LCD_Write_Char( 11, 1, AD_DATA[0]/51+0x30);//顯示輸入電壓的整數(shù)位
  LCD_Write_String(12,1, ".");//顯示小數(shù)點
  LCD_Write_Char( 13, 1, h_date/51/10%10+0x30);//顯示輸入電壓小數(shù)后1位
  LCD_Write_Char( 14, 1, h_date/51%10+0x30);//顯示輸入電壓小樹后2位
  LCD_Write_String(15,1, "V");

DelayMs(100) ;


}
}