/*
 Digital Thermometer using PIC16F877 and LM35 
 Oscillator @ 4MHz, MCLR Enabled, PWRT Enabled, WDT OFF 
*/ 
// LCD module connections 
sbit LCD_RS at RB0_bit; 
sbit LCD_EN at RB1_bit; 
sbit LCD_D4 at RB4_bit; 
sbit LCD_D5 at RB5_bit; 
sbit LCD_D6 at RB6_bit; 
sbit LCD_D7 at RB7_bit; 
sbit LCD_RS_Direction at TRISB0_bit; 
sbit LCD_EN_Direction at TRISB1_bit; 
sbit LCD_D4_Direction at TRISB4_bit; 
sbit LCD_D5_Direction at TRISB5_bit; 
sbit LCD_D6_Direction at TRISB6_bit; 
sbit LCD_D7_Direction at TRISB7_bit; 
// End LCD module connections 
// Define Messages 
char message0[] = "LCD Initialized"; 
char message1[] = "Room Temperature"; 
// String array to store temperature value to display 
char *tempC = "000.0"; 
char *tempF = "000.0"; 
// Variables to store temperature values 
unsigned int tempinF, tempinC; 
unsigned long temp_value; 
void Display_Temperature() { 
 // convert Temp to characters 
 if (tempinC/10000) 
  // 48 is the decimal character code value for displaying 0 on LCD 
  tempC[0] = tempinC/10000  + 48; 
 else tempC[0] = ' '; 
 tempC[1] = (tempinC/1000)%10 + 48;        // Extract tens digit 
 tempC[2] =  (tempinC/100)%10 + 48;          // Extract ones digit 
 // convert temp_fraction to characters 
 tempC[4] =  (tempinC/10)%10 + 48;        // Extract tens digit 
 // print temperature on LCD 
 Lcd_Out(2, 1, tempC); 
 if (tempinF/10000) 
  tempF[0] = tempinF/10000  + 48; 
 else tempF[0] = ' '; 
 tempF[1] = (tempinF/1000)%10 + 48;             // Extract tens digit 
 tempF[2] =  (tempinF/100)%10 + 48; 
 tempF[4] =  (tempinF/10)%10  + 48; 
 // print temperature on LCD 
 Lcd_Out(2, 10, tempF); 
} 
void main() { 
 ADCON0 = 0 ; // Connect AN0 to ADC module 
 ADCON1 = 0b00000101; // Connect AN0, select Vref=AN3 = 1.19V 
 TRISB = 0b00000000; // PORTC All Outputs 
 TRISA = 0b00001001; // PORTA All Outputs, Except RA0and RA3 
 Lcd_Init();                        // Initialize LCD 
 Lcd_Cmd(_LCD_CLEAR);               // CLEAR display 
 Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off 
 Lcd_Out(1,1,message0); 
 Delay_ms(1000); 
 Lcd_Out(1,1,message1);             // Write message1 in 1st row 
 // Print degree character 
 Lcd_Chr(2,6,223); 
 Lcd_Chr(2,15,223); 
 // Different LCD displays have different char code for degree symbol 
 // if you see greek alpha letter try typing 178 instead of 223 
 Lcd_Chr(2,7,'C'); 
 Lcd_Chr(2,16,'F'); 
 do { 
  temp_value = ADC_Read(0); 
  temp_value = temp_value*1168; 
  tempinC = temp_value/1000; 
  tempinC = tempinC*10; 
  tempinF = 9*tempinC/5 + 3200; 
  Display_Temperature(); 
  Delay_ms(1000);  // Temperature sampling at 1 sec interval 
 } while(1); 
}