protues中89c51+max1241采集电压，显示数值不随初始设定电阻值改变，恒定2.5V，求解

#include<regx52.h> 
#include<intrins.h>
unsigned char code table[16]=" THE RESULT: ";
unsigned char table1[]="0123456789";
unsigned char tab[]="0.00V";
sbit RS=P2^0;
sbit RW=P2^1;
sbit EN=P2^2;

void delay(unsigned int x)
{
  unsigned int k;
  for(k=0;k<x;k++);
}

unsigned int ad()
{
  unsigned int result = 0;
  unsigned char i;
  P1_7=0;
  P1_6=0;
  while(P1_5==0);
  for(i=0;i<12;i++)
  {
    P1_7=1;
    result<<=1;
    result|=P1_5;
    delay(200);
    P1_7=0;
    delay(200);
  }
  P1_7=0;
  P1_6=1;
  return result;
}

void write_com(unsigned char com)
{
  P0=com;
  RS=0;
  RW=0;
  EN=1;
  delay(200);
  EN=0;
}

void write_dat(unsigned char dat)
{
  P0=dat;
  RS=1;
  RW=0;
  EN=1;
  delay(200);
  EN=0;
}

void init()
{
  write_com(0x01);
  write_com(0x38);
  write_com(0x0f);
  write_com(0x06);
}

void main()
{
  unsigned char j;
  unsigned int t;
  t=ad()*5000.0/4096;
  tab[0]=t/1000+'0';
  tab[2]=(t/100)%10+'0';
  tab[3]=(t/10)%10+'0';
  init();
  write_com(0x80);
  for(j=0;j<16;j++)
  {
    write_dat(table[j]);
    delay(3000);
  }
  write_com(0xc0);
  for(j=0;j<5;j++)
  {
    write_dat(tab[j]);
    delay(3000);  
  }
  write_com(0x02);
  while(1);  
}

把功能放在while1里面，才能动态显示

void main()
{
  unsigned char j;
  unsigned int t;

  write_com(0x02);
  while(1)
{
  t=ad()*5000.0/4096;
  tab[0]=t/1000+'0';
  tab[2]=(t/100)%10+'0';
  tab[3]=(t/10)%10+'0';
  init();
  write_com(0x80);
  for(j=0;j<16;j++)
  {
    write_dat(table[j]);
    delay(3000);
  }
  write_com(0xc0);
  for(j=0;j<5;j++)
  {
    write_dat(tab[j]);
    delay(3000);  
  }
} 
}