LM35 and LCD Temperature Displaying with PIC18F4550 in CCS PICC

Referring to ADC module of PIC18F4550, there are many analog output sensor to interfaces with this MCU. LM35 is a simple analog temperature sensor, creating analog voltage output representing its temperature conversion in degree Celsius. The step temperature from this device is 10 mV per degree Celsius. I don't want to put all its details here. For more information about using this device, please see this post.

x2

x1.5

x1

x0.5

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In this post, LM35 connects to AN2 analog channel of the ADC. The MCU reads the analog voltage, converting it to temperature value in both degree Celsius and degree Fahrenheit.

A temperature reading of 31.2 degree Celsius.

A very simple LM35 comes in a transistor-like TO-92 package.

LM35DZ in TO-92 package.

C source code fed from GitHub.

	#include<18f4550.h>
	#device ADC=10
	/*Use high speed clock no PLL prescaler
	no system clock post scaler */
	#fuses HS,PLL1,CPUDIV1
	#use delay(clock=20M)
	#define LCD_ENABLE_PIN PIN_B2
	#define LCD_RS_PIN PIN_B0
	#define LCD_RW_PIN PIN_B1
	#define LCD_DATA4 PIN_B4
	#define LCD_DATA5 PIN_B5
	#define LCD_DATA6 PIN_B6
	#define LCD_DATA7 PIN_B7
	#include<lcd.c>
	void adcConfig(void){
	//RA3 As Input
	set_tris_a(0x04);
	//PORTD as output
	set_tris_d(0x00);
	//Set RA0...RA2 To Analog
	setup_adc_ports(AN0_TO_AN2);
	//Select ADC internal RC Clock
	setup_adc(ADC_CLOCK_INTERNAL);
	}
	float getTemperature(void){
	set_adc_channel(2);
	delay_ms(1);
	int16 analogValue=read_adc();
	while(!adc_done());
	float temperature = (analogValue*5.0)/1024;
	temperature*=100;
	return temperature;
	}
	void main(){
	float temp;
	lcd_init();
	adcConfig();
	while(1){
	lcd_gotoXy(1,1);
	printf(LCD_PUTC,"LM35 Temperature");
	lcd_gotoXy(1,2);
	temp=getTemperature();
	printf(LCD_PUTC,"%0.1f%cC %0.1f%cF ",temp,223,((temp*1.8)+32),223);
	delay_ms(250);
	}
	}

view raw lm35Lcd.c hosted with ❤ by GitHub

Click here to download the zip file of this example.

Schematic Diagram