MCU DS18b20 Temperature detection LCD display

/*-----------------------------------------------  

  Name: DS18b20 temperature detection LCD display  

  Forum: www.doflye.net  

  Written by: shifang  

  Date: 2009.5  

  Modification: None  

  content:  

------------------------------------------------*/  

#include //Include the header file. Generally, no modification is required. The header file contains the definition of special function registers.  

#include  

#include "18b20.h"  

#include "1602.h"  

#include "delay.h"  

#define KeyPort P3 //Define the key port  

bit ReadTempFlag; //define read time flag  

void Init_Timer0(void); //Timer initialization  

unsigned char KeyScan(void); //keyboard scan  

/*------------------------------------------------  

              Serial communication initialization  

------------------------------------------------*/  

void UART_Init(void)  

{  

    SCON = 0x50; // SCON: Mode 1, 8-bit UART, receive enabled    

    TMOD |= 0x20;               // TMOD: timer 1, mode 2, 8-bit 重装  

    TH1 = 0xFD; // TH1: reload value 9600 baud rate crystal 11.0592MHz    

    TR1 = 1; // TR1: timer 1 is turned on                           

    //EA = 1; //Open the general interrupt  

    //ES = 1; //Open serial port interrupt  

IF=1;  

}  

/*------------------------------------------------  

                    Main function  

------------------------------------------------*/  

void main (void)  

{                    

int temp,tempH=50,tempL=1;  

float temperature;  

unsigned char TempFlag=0;  

char displaytemp[16],num; //define the temporary storage array of the display area  

LCD_Init(); //Initialize LCD  

DelayMs(20); //Delay helps to stabilize  

LCD_Clear(); //Clearing  

Init_Timer0();  

UART_Init();  

Lcd_User_Chr(); //Write custom characters  

while (1) //main loop  

  {  

 num=KeyScan();  

 switch(num)  

       {  

   case 1:if(tempH<127)tempH++;break;  

case 2:if(tempH>-55)tempH--;break;  

case 3:if(tempL<127)tempL++;break;  

case 4:if(tempL>-55)tempL--;break;  

default:break;  

  }  

switch(TempFlag)  

       {  

   case 0: // Output temperature upper and lower limits  

     sprintf(displaytemp,"H.%3d  L.%3d ",tempH,tempL);  

              LCD_Write_String(0,1,displaytemp);//Display the second line  

 break;  

case 1:LCD_Write_String(0,1,"over  tempH    ");break;  

case 2:LCD_Write_String(0,1,"under  tempL   ");break;  

default:break;  

  }  

if(ReadTempFlag==1)  

 {  

  ReadTempFlag=0;  

  temp=ReadTemperature();  

  temperature=temp*0.0625;  

  temp>>=4;  

 if(temp>tempH)  

    TempFlag=1; //Higher than high temperature flag  

 else if(temp

    TempFlag=2; //Below low temperature flag  

 else  

   TempFlag=0; //Normal display flag  

  sprintf(displaytemp,"Temp %6.2f ",temperature); //Print temperature value  

  LCD_Write_String(0,0,displaytemp);//Display the first line  

  LCD_Write_Char(13,0,0x01); //Write the upper right corner of the temperature  

  LCD_Write_Char(14,0,'C'); //Write character C  

  }   

 }  

}  

/*------------------------------------------------  

                    Timer initialization subroutine  

------------------------------------------------*/  

void Init_Timer0(void)  

{  

 TMOD |= 0x01; //Use mode 1, 16-bit timer, use the "|" symbol to avoid being affected when using multiple timers  

 //TH0=0x00; //Give initial value  

 //TL0=0x00;  

 EA=1; //General interrupt is turned on  

 ET0=1; //Timer interrupt is turned on  

 TR0=1; //Timer switch is turned on  

}  

/*------------------------------------------------  

                 Timer interrupt subroutine  

------------------------------------------------*/  

void Timer0_isr(void) interrupt 1   

{  

 static unsigned int num;  

 TH0=(65536-2000)/256; //Reassign 2ms  

 TL0=(65536-2000)%256;  

 num++;  

 if(num==400)        //  

   {  

    num=0;  

    ReadTempFlag=1; //Read flag position 1  

}  

}  

/*------------------------------------------------  

Key scanning function, returns the scanned key value  

------------------------------------------------*/  

unsigned char KeyScan(void)  

{  

 unsigned char keyvalue;  

 if(KeyPort!=0xff)  

   {  

    DelayMs(10);  

    if(KeyPort!=0xff)  

  {  

   keyvalue=KeyPort;  

   while(KeyPort!=0xff);  

switch(keyvalue)  

{  

case 0xfe:return 1;break;  

case 0xfd:return 2;break;  

case 0xfb:return 3;break;  

case 0xf7:return 4;break;  

case 0xef:return 5;break;  

case 0xdf:return 6;break;  

case 0xbf:return 7;break;  

case 0x7f:return 8;break;  

default:return 0;break;  

}  

 }  

   }  

   return 0;  

}