基于51单片机的直流数字电压表（0-5V）

叶致习 · 发表于 2016-4-27 01:15:54

利用串行A/D转换器TLC549对输入信号电压源进行采集转换成数字信号给51单片机，经单片机进行数据处理后给1602液晶显示。
误差小于1%.
#include<reg52.h>
#include<intrins.h>
#define uint unsigned int
#define uchar unsigned char
uchar LCD[6]; //电压数据转换成LCD1602液晶字符显示
uint Volt;
sbit DO  = P1^0;       //时钟
sbit CS  = P1^1;       //片选
sbit CLK = P1^2;       //数据输出
sbit RS = P2^0;                      //1602液晶数据/命令选择端
sbit RW = P2^1;                      //1602液晶读写端
sbit E  = P2^2;                      //1602液晶使能端

// Function Prototypes
void check_busy(void);
void write_command(uchar com);
void write_date(uchar date);
void LCD_init(void);
void string(uchar ad ,uchar *s);
//void lcd_test(void);
void delay(uint);
void Volt_To_LCD1602(void);
void delay_ms(uint xms);
void Data_Conversion(void);
uchar TLC549_ADC(void);
/*******************************************
LCD1602 Driver mapped as IO peripheral
*******************************************/
// Delay
// Delay
void delay(uint j)
{
      uchar i = 60;
  for(; j>0; j--)
  {
            while(--i);
i = 59;
while(--i);
i = 60;
  }
}

// Test the Busy bit
void check_busy(void)
{
      do
  {
            P0 = 0xff;
E = 0;
RS = 0;
RW = 1;
E = 1;
_nop_();
  } while(P0 & 0x80);
  E = 0;
}

// Write a command
void write_command(uchar com)
{
      check_busy();
  E = 0;
  RS = 0;
  RW = 0;
  P0 = com;
  E = 1;
  _nop_();
  E = 0;
  delay(1);
}

// Write Data
void write_date(uchar date)
{
      check_busy();
  E = 0;
  RS = 1;
  RW = 0;
  P0 = date;
  E = 1;
  _nop_();
  E = 0;
  delay(1);
}

// Initialize LCD controller
void LCD_init(void)
{
      write_command(0x38); // 8-bits, 2 lines, 7x5 dots
  write_command(0x0C); // no cursor, no blink, enable display
  write_command(0x06); // auto-increment on
  write_command(0x01); // clear screen
  delay(1);
}

// Display a string
void string(uchar ad, uchar *s)
{
      write_command(ad);
  while(*s>0)
  {
               write_date(*s++);
   delay(100);
  }
}
//****************************************************//
//函数名:delay_ms(uint xms)
//函数功能:ms级延时函数
//***************************************************//

void delay_ms(uint xms)
{
      uint x,y;
      for(x=xms;x>0;x--)
            for(y=110;y>0;y--);

}

//***************************************************//
//函数名称:TLC549_ADC()
//函数功能:读取上一次A/D转换的数据,启动下一次A/D转换
//**************************************************//
uchar TLC549_ADC(void)
{
      uchar n, tmp;

      CS  = 1;                   //CS置高,片选无效
      CLK = 0;

      CS  = 0;                   //CS置低,片选有效,同时DO输出高位
      _nop_();
      _nop_();                   //适当延迟时间1.4us Setup Time

      for(n = 0; n < 8; n++) //串行数据移位输入
      {
            tmp <<= 1;
            tmp |=  DO;

            CLK = 1;       //0.4us
            _nop_();       //CLK transition time Max 0.1us
            CLK = 0;       //0.4us
      }
      CS = 1;          //CS置高,片选无效
      for(n = 17; n != 0; n--) _nop_();  //Next Coversion需要延迟17us
      return (tmp);
}
//****************************************//
//函数名称

ata_Conversion()
//函数功能:电压换算
//*****************************************//
void Data_Conversion(void)
{
      uchar AD_Data;

      AD_Data = TLC549_ADC();
      delay_ms(1000);
      Volt = 5.0 / 256 * AD_Data*1000;
}

void Volt_To_LCD1602(void)
{
      Data_Conversion();                   //电压换算并放大1000倍
      LCD[0] = Volt/1000;       //千位
      LCD[1] = '.';                               //小数点
      LCD[2] = Volt/100%10;  //百位
      LCD[3] = Volt/10%10; //十位
      LCD[4] = Volt%10;          //个位
      LCD[5] = 'V';                            //字符V

      write_command(0x80+8);
      write_date(0x30+LCD[0]);
      write_date(LCD[1]);
      write_date(0x30+LCD[2]);
      write_date(0x30+LCD[3]);
      write_date(0x30+LCD[4]);
      write_date(LCD[5]);

}

int main()
{
      //uint m;
      LCD_init();

  delay(100);
  write_command(0x01);
      write_command(0x80);
      string(0x80,"Voltage:");
      delay_ms(2000);

      while(1)
      {
            Volt_To_LCD1602();

      }

}