microcontroller 5

Rotary Encoder Interfacing with PIC Microcontroller

Components Required

It is the time to identify what we need to interface Rotary Encoder with PIC Microcontroller,

1. PIC16F877A
2. 4.7k resistor
3. 1k resistor
4. 10k pot
5. 33pF ceramic disc capacitor – 2pcs
6. 20Mhz crystal
7. 16x2 Display
8. Rotary Encoder
9. 5V adapter.
10. Bread Board
11. Hookup wires.

Project Code

/*

 * File:   main.c

 * Author: Sourav Gupta

 *

 * Created on 18 Dec 2018, 18:57

 */

 

/*

 * Configuration Related settings. Specific for microcontroller unit.

 */

#pragma config FOSC = HS        // Oscillator Selection bits (HS oscillator)

#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT disabled)

#pragma config PWRTE = OFF      // Power-up Timer Enable bit (PWRT disabled)

#pragma config BOREN = ON       // Brown-out Reset Enable bit (BOR enabled)

#pragma config LVP = OFF         // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3/PGM pin has PGM function; low-voltage programming enabled)

#pragma config CPD = OFF        // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)

#pragma config WRT = OFF        // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)

#pragma config CP = OFF         // Flash Program Memory Code Protection bit (Code protection off)

#define _XTAL_FREQ 20000000

/*

 * System Header files inclusions

 */

 

#include <xc.h>

//#include <string.h>

#include <stdlib.h>

#include "supporting c files/lcd.h"

 

#define Encoder_SW PORTDbits.RD2

#define Encoder_DT PORTDbits.RD3

#define Encoder_CLK PORTCbits.RC4

 

/*

 * Program flow related functions

 */

int counter; // It will hold the count of rotary encoder.

int position; // It will store the rotary encoder position.

void sw_delayms(unsigned int d);

int value[7];

 

/*

 * System Init Function

 */

 

void system_init ();

 

/* Main function single Thread*/

void main(void) {

    system_init();

    lcd_puts ("Circuit Digest");

    lcd_com(0xC0);

    counter = 0;

    while(1){

        lcd_com(0xC0);

        if (Encoder_SW == 0){

            sw_delayms(20);

            if (Encoder_SW == 0){

                //lcd_com(1);

                //lcd_com(0xC0);

                lcd_puts ("switch pressed");

//                itoa(counter, value, 10);

//                lcd_puts(value);

            }

        }                       

       if (Encoder_CLK != position){

            if (Encoder_DT != position){

               // lcd_com (0x01);

                counter++;

                lcd_com (0xC0);

                lcd_puts("                ");

                lcd_com (0xC0);

                lcd_bcd(1,counter);

            }

            else{

               // lcd_com (0x01);

                lcd_com (0xC0);

                counter--;

                lcd_puts("                ");

                lcd_com (0xC0);

                lcd_bcd(1,counter);

                //lcd_puts("Left");

            }           

        }

        position = Encoder_CLK;                

 

}

 

    return;

}

 

void sw_delayms(unsigned int d){

int x, y;

for(x=0;x<d;x++)

for(y=0;y<=1275;y++);

}

 

void system_init(){

    TRISB = 0x00; // PORT B as output, This port is used for LCD    

    TRISDbits.TRISD2 = 1;

    TRISDbits.TRISD3 = 1;

    TRISCbits.TRISC4 = 1;

    lcd_init(); // This will Initialize the LCD

    position = Encoder_CLK;// Sotred the CLK position on system init, before the while loop start.

}