How to work with inbuilt ADC Module of PIC Microcontroller (PIC18F4550)

Project Source Code

###

// Program to depict working with inbuilt ADC of PIC18F4550 Microcontroller
// This code uses Channel0 (zero) of PIC’s ADC Module

// Configuration bits
/* _CPUDIV_OSC1_PLL2_1L, // Divide clock by 2
_FOSC_HS_1H, // Select High Speed (HS) oscillator
_WDT_OFF_2H, // Watchdog Timer off
MCLRE_ON_3H // Master Clear on
*/

#define rs LATA.F0
#define rw LATA.F1
#define en LATA.F2
#define lcdport LATB

void lcd_ini();
void lcdcmd(unsigned char);
void lcddata(unsigned char);
void adc_con(unsigned int);
void adc_init();

unsigned char data[20]=”ADC OUTPUT=”;
unsigned int digital_out[10],avg_output=0,temp;
unsigned int i=0;

void main()
{
TRISA=0x01; // Configure RA0 as input pin
LATA=0;
TRISB=0; // Configure Port B as output port
LATB=0;
TRISD=0;
LATD=0;
lcd_ini(); // LCD initialization
while(data[i]!=”)
{
lcddata(data[i]); // Call lcddata function to send character one by from ‘data’ array
i++;
}

adc_init(); //ADC Initialization

while(1)
{
temp=0;
for(i=0;i<10;i++)
{
ADCON0|=(1<<GO); // Start A/D conversion
while(!(ADCON0 & (1<<GO))); // Wait until conversion gets over
digital_out[i]=((ADRESL)|(ADRESH<<8)); // Store 10-bit output into a 16-bit variable
Delay_ms(20);
temp=temp+digital_out[i];
}
avg_output=temp/10; // Take average of ten digital values for stablity
adc_con(avg_output); // Function to convert the decimal vaule to its corresponding ASCII

}
}

void adc_init()
{
ADCON1=0x0E; // Make RA0/AN0 pin as analog pin (Other pins remain to be digital I/O)
ADCON0=0x00; // Select Channel0 & ADC off
ADCON2=0x8A; // Left justified, 2TAD acquiciation time, Fosc/32 clock option
ADCON0.ADON=1; // Enable ADC
}

void lcd_ini()
{
lcdcmd(0x38); // Configure the LCD in 8-bit mode, 2 line and 5×7 font
lcdcmd(0x0C); // Display On and Cursor Off
lcdcmd(0x01); // Clear display screen
lcdcmd(0x06); // Increment cursor
lcdcmd(0x80); // Set cursor position to 1st line, 1st column
}

void adc_con(unsigned int adc_out)
{
unsigned int adc_out1;
int i=0;
char position=0xC3;

for(i=0;i<=3;i++)
{
adc_out1=adc_out%10; // To exract the unit position digit
adc_out=adc_out/10;
lcdcmd(position);
lcddata(48+adc_out1); // Convert into its corresponding ASCII
position–;

}
}

void lcdcmd(unsigned char cmdout)
{
lcdport=cmdout; //Send command to lcdport=PORTB
rs=0;
rw=0;
en=1;
Delay_ms(10);
en=0;
}

void lcddata(unsigned char dataout)
{
lcdport=dataout; //Send data to lcdport=PORTB
rs=1;
rw=0;
en=1;
Delay_ms(10);
en=0;
}

###

Circuit Diagrams

Project Components

Project Video