Выход из процедуры прерывания в PIC16F18877

После выполнения блока прерывания выполнение останавливается и никогда не возвращается из процедуры прерывания в блок while(1) в основном методе.

Чтобы проверить функциональность, я написал приведенный ниже код для проверки прерывания.

 /*
 * File:   stepper.c
 * Author: vsathyan
 *
 * Created on August 30, 2019, 11:04 AM
 */

// PIC16F18877 Configuration Bit Settings

// 'C' source line config statements

// CONFIG1
#pragma config FEXTOSC = HS     // External Oscillator mode selection bits (HS (crystal oscillator) above 4MHz; PFM set to high power)
#pragma config RSTOSC = EXT1X   // Power-up default value for COSC bits (EXTOSC operating per FEXTOSC bits)
#pragma config CLKOUTEN = OFF   // Clock Out Enable bit (CLKOUT function is disabled; i/o or oscillator function on OSC2)
#pragma config CSWEN = ON       // Clock Switch Enable bit (Writing to NOSC and NDIV is allowed)
#pragma config FCMEN = ON       // Fail-Safe Clock Monitor Enable bit (FSCM timer enabled)

// CONFIG2
#pragma config MCLRE = ON       // Master Clear Enable bit (MCLR pin is Master Clear function)
#pragma config PWRTE = OFF      // Power-up Timer Enable bit (PWRT disabled)
#pragma config LPBOREN = OFF    // Low-Power BOR enable bit (ULPBOR disabled)
#pragma config BOREN = OFF      // Brown-out reset enable bits (Brown-out reset disabled)
#pragma config BORV = LO        // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (VBOR) set to 1.9V on LF, and 2.45V on F Devices)
#pragma config ZCD = OFF        // Zero-cross detect disable (Zero-cross detect circuit is disabled at POR.)
#pragma config PPS1WAY = ON     // Peripheral Pin Select one-way control (The PPSLOCK bit can be cleared and set only once in software)
#pragma config STVREN = OFF     // Stack Overflow/Underflow Reset Enable bit (Stack Overflow or Underflow will not cause a reset)

// CONFIG3
#pragma config WDTCPS = WDTCPS_31// WDT Period Select bits (Divider ratio 1:65536; software control of WDTPS)
#pragma config WDTE = OFF       // WDT operating mode (WDT Disabled, SWDTEN is ignored)
#pragma config WDTCWS = WDTCWS_7// WDT Window Select bits (window always open (100%); software control; keyed access not required)
#pragma config WDTCCS = SC      // WDT input clock selector (Software Control)

// CONFIG4
#pragma config WRT = OFF        // UserNVM self-write protection bits (Write protection off)
#pragma config SCANE = not_available// Scanner Enable bit (Scanner module is not available for use)
#pragma config LVP = ON         // Low Voltage Programming Enable bit (Low Voltage programming enabled. MCLR/Vpp pin function is MCLR.)

// CONFIG5
#pragma config CP = ON          // UserNVM Program memory code protection bit (Program Memory code protection enabled)
#pragma config CPD = ON         // DataNVM code protection bit (Data EEPROM code protection enabled)

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

#define _XTAL_FREQ 4000000

//LCD DISPLAY INTERFACE - PORTD & PORTE
#define RS RD2
#define EN RD3
#define D4 RC4
#define D5 RC3
#define D6 RD0
#define D7 RD1

#define TRIS_RS TRISD2
#define TRIS_EN TRISD3
#define TRIS_D4 TRISC4
#define TRIS_D5 TRISC3
#define TRIS_D6 TRISD0
#define TRIS_D7 TRISD1

#define BUZZER RC1
#define TRIS_BUZZER TRISC1

#define OUTPUT 0
#define INPUT 1

#define PRESSED 1
#define RELEASED 0
#define _PRESSED 0
#define _RELEASED 1

#define SET 1
#define CLEAR 0

#define HIGH 1
#define LOW 0

#define UP 1
#define DOWN 0

//INPUT CONFIGURATION
#define EMERGENCY_BUTTON RB0
#define MENU_OPTION RB1
#define VALUE_UP RB2
#define VALUE_DOWN RB3
#define SET_VALUE RB4
#define HOME_LIMIT_SWITCH RB5
#define END_LIMIT_SWITCH RB6

#define TRIS_EMERGENCY_BUTTON TRISB0
#define TRIS_MENU_OPTION TRISB1
#define TRIS_VALUE_UP TRISB2
#define TRIS_VALUE_DOWN TRISB3
#define TRIS_SET_VALUE TRISB4
#define TRIS_HOME_LIMIT_SWITCH TRISB5
#define TRIS_END_LIMIT_SWITCH TRISB6

//OUTPUT CONFIGURATION
#define PULSE RA0
#define DIRECTION RA1
#define ENABLE RA2

#define TRIS_PULSE TRISA0
#define TRIS_DIRECTION TRISA1
#define TRIS_ENABLE TRISA2

//function declarations
void showMessage(char *message1, char *message2);
void initializeVariables();

//program variables
char fValue[16];
int option;

#include <xc.h>
#include <stdio.h>
#include <string.h>
#include "stepper.h"
#include "lcd162.h"


//function declarations
void showMessage(char *message1, char *message2);
void showMessageWithDelay(char *message1, char *message2, int delay);
void initialize();
void initializeVariables();
void setStringValue(char stringValue, float floatValue);
void delay_ms(int delay);
void delay_us(int delay);

void interrupt isr()
{
    if(IOCIF) //if interrupt on change flag is set
    {
        if(IOCBF1) //if interrupt on port RB1 is set
        {
            showMessageWithDelay(" RB1 Interrupt  ", "                ", 3000); //display a message in LCD for 3 seconds
            IOCBF1 = 0;
        }
        IOCIF = 0;
    }
    showMessageWithDelay(" End ISR Method ", "                ", 3000); //display a message in LCD for 3 seconds
    return; //return to main program execution
}

void main(void) 
{
    initialize(); //initialize input pins, output pins, variables
    Lcd_Start(); //initialize 16x2 LCD
    Lcd_Clear(); //clear LCD;
    showMessageWithDelay("Automatic Speed ", "Controller V0.1 ", 3000); //display start message
    int i = 0;
    while(1)
    {
        i = i + 1;
        setStringValue(fValue, i);
        showMessageWithDelay("  Inside While  ", fValue, 1000); //message displayed when inside infinite while loop
    }
}
void showMessage(char *message1, char *message2)
{
    Lcd_Clear();
    Lcd_Set_Cursor(1,1);
    Lcd_Print_String(message1);
    Lcd_Set_Cursor(2,1);
    Lcd_Print_String(message2);
}
void showMessageWithDelay(char *message1, char *message2, int delay)
{
    Lcd_Clear();
    Lcd_Set_Cursor(1,1);
    Lcd_Print_String(message1);
    Lcd_Set_Cursor(2,1);
    Lcd_Print_String(message2);
    delay_ms(delay);
}
void initialize()
{
    ANSELA = 0x00;
    ANSELB = 0x00; //disable analog input on port B
    ANSELC = 0x00;
    ANSELD = 0x00;
    ANSE0 = 0;
    ANSE1 = 0;
    ANSE2 = 0;

    WPUB = 0xFF; //enable weak pull up resistors on all port B pins
    TRISB = 0xFF; //all port B pins are inputs
    IOCBP = 0xFF; //interrupt on change positive trigger enabled on port B;
    IOCBN = 0xFF; //interrupt on change negative trigger enabled on port B;
    IOCBF = 0x00; //clear RB1 interrupt flag

    TRISA = 0x00; //set PORTA as output port
    PORTA = 0x00; //set all PORTA bit values to 0

    TRIS_RS = OUTPUT;
    TRIS_EN = OUTPUT;
    TRIS_D4 = OUTPUT;
    TRIS_D5 = OUTPUT;
    TRIS_D6 = OUTPUT;
    TRIS_D7 = OUTPUT;

    TRIS_BUZZER = OUTPUT;

    TRIS_PULSE = OUTPUT;
    TRIS_DIRECTION = OUTPUT;
    TRIS_ENABLE = OUTPUT;

    PULSE = 0;
    ENABLE = 0;
    DIRECTION = 0;

    IOCIE = 1; //enable INTERRUPT ON CHANGE 
    PEIE = 1; //enable PERIPHERAL INTERRUPT
    GIE = 1; //enable GLOBAL INTERRUPT
    initializeVariables();

}
void initializeVariables()
{
    option = 0;
}
void setStringValue(char stringValue, float floatValue)
{
    sprintf(stringValue, "%.3f", floatValue);
}
void delay_ms(int delay)
{
    for(int i = 0; i < delay; i++)
    {
        __delay_ms(1);
    }
}
void delay_us(int delay)
{
    for(int i = 0; i < delay; i++)
    {
        __delay_us(1);
    }
}

Сообщение, которое я вижу на светодиоде, называется «Конец метода ISR», и оно никогда не переходит в бесконечность после выполнения ISR.

Я проверил инструкцию RETFIE, но я использую C, а не язык ассемблера. Я использовал обычный оператор «возврата» C в конце процедуры прерывания, но, похоже, выполнение там застревает.

Что я делаю не так? Любые исправления в этом коде, пожалуйста?