---
title: LM35 Project Software
slug: lm35-project-software
docTags: 
createdAt: 2024-02-22T14:24:32.502Z
---

The firmware required to interface with the sensor performs several tasks.

- Configures the microcontroller to read the analog value
- Converts the analog value to a digital number
- Formats that value for export 

## Microcontroller 

The device chosen is the PIC16F887, and while it is far more in terms of resources it will provide a good base to build on and with for later projects or adding on additional features.

What is needed from the microcontroller is:

- One of the Analog Inputs
- PORTB for the LCD Display
- Comport to share the data with the outside world

### Full Code Sample

The full code sample is shown below and can be copied from the code block.

The code sample is also available from GitHub.

```c
unsigned char ch;
unsigned int adc_rd;
char *text;
long tlong;
char *tempc = "000.0";

void deviceSetup(){
  INTCON = 0;                              // disable all interrupts
  
  ANSEL  = 0x04;                           // Configure AN2 pin as analog input
  TRISA  = 0x04;
  ANSELH = 0;  
  ADCON1 = 0x82;                       // configure VDD as Vref, and analog channels
  TRISA  = 0xFF;                       // designate PORTA as input  

  UART1_Init(9600);
  Delay_ms(100);
}

void main() {
                            
  Lcd_Config(&PORTB, 4, 5, 6, 3, 2, 1, 0); // Lcd_Init_EP5, see Autocomplete
  LCD_Cmd(LCD_CURSOR_OFF);                 // send command to LCD (cursor off)
  LCD_Cmd(LCD_CLEAR);                      // send command  to LCD (clear LCD)

  text = "LM 35 Project";               // assign text to string
  LCD_Out(1,1,text);                       // print string a on LCD, 1st row, 1st column
    
  Delay_ms(2000);
  text  = "Temp:";                      // assign text to string


  while (1) {
    adc_rd  = ADC_read(2);                 // get ADC value from 2nd channel
    LCD_Out(2,1,text);                     // print string a on LCD, 2nd row, 1st column

    tlong = (long)adc_rd * 5000;           // covert adc reading to milivolts
    tlong = tlong / 1023;                  // 0..1023 -> 0-5000mV
    
    ch = tlong / 1000;                 // extract leading temp digit
    tempc[1] = ch+48;
    
    ch = (tlong / 100) % 10;            // extract 0.1 temp digit
    LCD_Chr_CP(48+ch);                     // write ASCII digit at cursor point
    tempc[2] = ch+48;

    ch = (tlong / 10) % 10;             // extract 0.01 temp digit
    tempc[3] = ch+48;
    LCD_Chr_CP(48+ch);                     // write ASCII digit at cursor point
    LCD_Chr_CP(48+ch);                     // write ASCII digit at cursor point
    LCD_Chr_CP('C');
    tempc[4] = ch+48;
    
    UART1_Write(tempc[2]);
    UART1_Write(tempc[3]);
    UART1_Write_Text(".");
    UART1_Write(tempc[4]);
    
    UART1_Write(13);
    UART1_Write(10);
    Delay_ms(100);    
    
  }
}//~!
```