仿真時候，報警器和蜂鳴器正常響，但是LCD不顯示溫度。
代碼如下：#include <reg52.h>//頭文件，52單片機改為52
#include <intrins.h>
#define LCD_DATA P0
sbit LCD_RS = P2^0;
sbit LCD_RW = P2^1;
sbit LCD_EN = P2^2;
unsigned char dispBuff0[16]={'T','E','M',
'P',':',' ',' ',' ',' ',' ',' ','C',' ',' ',' ',};//LCD第一行顯示
sbit DQ=P2^3; //DS18B20數據端
unsigned int temperature=0;//溫度
unsigned char fuhao=0;//溫度的正負符號
//LED報警指示的IO口以及變量定義
sbit LED1=P2^4;//溫度報警指示
#define off 1 //高電平時燈為關閉狀態
#define on 0 //低電平時燈為開啟狀態
sbit speaker=P3^1;//蜂鳴器
void Delay20ms() ;
void LCD_WriteDat(unsigned char lcd_dat);
void LCD_WriteCmd(unsigned char lcd_cmd);
unsigned char LCD_ReadStatus(void);
void LCD_Goto(unsigned char x,unsigned char y);
void LCD_Display(unsigned char row,unsigned char *str);
void delay(unsigned int x)//延時公用程序
{
unsigned char j;
while(x--)
{
for(j=0;j<125;j++);
}
}
/*1、LCD模塊子函數*/
void LCD_Init(void)
{
Delay20ms();
LCD_WriteCmd(0x38); //8位機接口、雙行顯示、5×7字符點陣；
LCD_WriteCmd(0x0c); //顯示開啟、光標不顯示也不閃爍；
LCD_WriteCmd(0x01); //清屏；
LCD_WriteCmd(0x06); //光標右移一位、整屏不移動；
LCD_Goto(0,0);
}
void LCD_WriteDat(unsigned char lcd_dat)
{
unsigned char tmp;
tmp = LCD_ReadStatus(); //讀狀態；
while((tmp & 0x80)) //是否忙 ?
{
tmp = LCD_ReadStatus();
}
LCD_RS = 1;
LCD_RW = 0;
LCD_DATA = lcd_dat;
_nop_();
LCD_EN = 0;
_nop_();
_nop_();
LCD_EN = 1;
}
void LCD_WriteCmd(unsigned char lcd_cmd)
{
unsigned char tmp;
tmp = LCD_ReadStatus();
while((tmp & 0x80))
{
tmp = LCD_ReadStatus();
}
LCD_RS = 0;
LCD_RW = 0;
LCD_DATA = lcd_cmd;
_nop_();
LCD_EN = 0;
_nop_();
_nop_();
LCD_EN = 1;
}
unsigned char LCD_ReadStatus(void)
{
unsigned char tmp;
#if 0
LCD_RS = 0;
LCD_RW = 1;
LCD_EN = 1;
tmp = LCD_DATA;
LCD_EN = 0;
#endif
LCD_DATA = 0xff;
LCD_RS = 0;
LCD_RW = 1;
LCD_EN = 0;
_nop_();
_nop_();
LCD_EN = 1;
tmp = LCD_DATA;
return tmp;
}
void LCD_Goto(unsigned char x,unsigned char y)
{
unsigned char tmp;
if(y) //若是第二行；
{
tmp = 0xc0 + x;
LCD_WriteCmd(tmp);
}
else
{
tmp = 0x80 + x;
LCD_WriteCmd(tmp);
}
}
void LCD_Display(unsigned char row,unsigned char *str)
{
if(row)
{
LCD_Goto(0,1);
}
else
{
LCD_Goto(0,0);
}
while(*str != '\0')
{
LCD_WriteDat(*str++);
}
}
void Delay20ms() //粗略延時；
{
unsigned int tmp = 50000;
while(tmp--);
}
/*2、DS18B2模塊*/
void delay_18B20(unsigned int i)
{
while(i--);
}
/**********ds18b20初始化函數**********************/
void Init_DS18B20(void)
{
unsigned char x=0;
DQ = 1; //DQ復位
delay_18B20(2); //稍做延時
DQ = 0; //單片機將DQ拉低
delay_18B20(60); //精確延時 大于 480us
DQ = 1; //拉高總線
delay_18B20(2);
x=DQ; //稍做延時后 如果x=0則初始化成功 x=1則初始化失敗
delay_18B20(15);
}
/***********ds18b20讀一個字節**************/
unsigned char ReadOneChar(void)
{
unsigned char i=0;
unsigned char dat = 0;
for (i=8;i>0;i--)
{
DQ = 0; // 給脈沖信號
dat>>=1;
DQ = 1; // 給脈沖信號
if(DQ)
dat |=0x80;
delay_18B20(4);
}
return(dat);
}
/*************ds18b20寫一個字節****************/
void WriteOneChar(unsigned char dat)
{
unsigned char i=0;
for (i=8; i>0; i--)
{
DQ = 0;
DQ = dat&0x01;
delay_18B20(2);
DQ = 1;
dat>>=1;
}
}
void ReadTemperature(void)
{unsigned char readdata[2]={0,0};
fuhao=0;
temperature=0;
delay_18B20(40); // this message is very important
Init_DS18B20();
WriteOneChar(0xCC); // 跳過讀序號列號的操作
WriteOneChar(0x44); // 啟動溫度轉換
delay_18B20(40); // this message is wery important
Init_DS18B20();
WriteOneChar(0xCC); //跳過讀序號列號的操作
WriteOneChar(0xBE); //讀取溫度寄存器等（共可讀9個寄存器） 前兩個就是溫度
delay_18B20(40);
readdata[0]=ReadOneChar(); //讀取溫度值低位
readdata[1]=ReadOneChar(); //讀取溫度值高位
if (readdata[1]>127)
{readdata[0]^=0xff;//求補碼
readdata[1]^=0xff;
fuhao=1;//符號為“-”
}
temperature =readdata[1]*256+readdata[0] ;
temperature =temperature*0.625+0.5 ;//放大了10倍
}
void timer0() interrupt 1 //這里輸出蜂鳴器信號
{TH0=254;//頻率為1600hz時計時器初值
TL0=200;
speaker=!speaker;
}
void main()
{unsigned char DEN=0;
LCD_Init();//初始化LCD
/*計時器0設置*/
TMOD=0x11;//定時器1、2工作于方式1
TH0=254;//頻率為1600hz時計時器初值
TL0=200;
ET0=1;
EA=1;
speaker=1;
while(1)
{
/*LCD第一行顯示溫度*/
ReadTemperature();//讀取溫度值
if (fuhao)
{dispBuff0[5]='-';}
else
{dispBuff0[5]='+';}
dispBuff0[6]=(temperature/1000)%10+'0';//溫度值百位
dispBuff0[7]=(temperature/100)%10+'0';//溫度值十位
dispBuff0[8]=(temperature/10)%10+'0';//溫度值個位
dispBuff0[9]='.';
dispBuff0[10]=(temperature)%10+'0';//溫度值小數點后一位;
/*報警程序*/
if (temperature>=330 && !fuhao)//溫度大于40攝氏度
{LED1=on;}
else
{LED1=off;}
if (temperature>=330 && !fuhao)//響蜂鳴器
{TR0=1;}
else
{TR0=0;}
}//while
}//main
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