// PIC18 in C - Versione 0.4 - Febbraio 2016
// Copyright (c) 2014-2016, Vincenzo Villa
// Creative Commons | Attribuzione - Condividi allo stesso modo 4.0 Internazionale (CC BY-SA 4.0)
// Creative Commons | Attribution-Share Alike 4.0 Unported
// https://www.vincenzov.net/tutorial/PIC18/interrupt.htm

// PIC18F2xK20 / MPLAB X IDE v3.25 / XC8 1.35

// External interrupt INT0 (high priority) and INT1 (low priority)

#include "configurationsbits-PIC18F25K20.h"

#define _XTAL_FREQ 1000000 // Main clock frequency (Default: 1 MHz)

void configureRegisters(void); // Configure PIC18 registers

// ***** main() code ***** 

void main(void) {

    configureRegisters();

    // Enable interrupt 
    INTCONbits.GIEH = 1; // 1 = Enables all high priority interrupts
    INTCONbits.GIEL = 1; // 1 = Enables all low priority interrupts

    while (1) { // Blink RC7, forever
        LATCbits.LATC7 = ~LATCbits.LATC7;
        __delay_ms(250);
    }
}

// ***** ISR ***** 

void interrupt __high_priority my_isr_high(void) {
    if (INTCONbits.INT0F == 1) { // INT0 external interrupt occurred ?
        LATCbits.LATC6 = 0; // Turn off RC6 pin
        INTCONbits.INT0F = 0; // Clear INT0 flag
    }
    //  if (XXX.flag == 1) { // XXX interrupt occurred ? (NOT USED HERE)
    //      ...
    //      XXX.flag = 0; // Clear XXX flag
    //    }
    return;
}

void interrupt __low_priority my_isr_low(void) {
    if (INTCON3bits.INT1IF == 1) { // INT1 external interrupt occurred ?
        LATCbits.LATC5 = 0; // Turn off RC5 pin
        INTCON3bits.INT1IF = 0; // Clear INT1 flag
    }
    //  if (XXX.flag == 1) { // XXX interrupt occurred ? (NOT USED HERE)
    //      ...
    //      XXX.flag = 0; // Clear XXX flag
    //    }
    return;
}

// ***** Configure ports and interrupt ***** 

void configureRegisters(void) {

    // ***** Configure Port C *****
    
    TRISCbits.RC7 = 0; // Configure RC5 -> RC7 as output
    TRISCbits.RC6 = 0;
    TRISCbits.RC5 = 0;
    LATCbits.LATC5 = 1; // Turn on LEDs on RC5 -> RC7
    LATCbits.LATC6 = 1;
    LATCbits.LATC7 = 1;
    
    // *****  Configure Port B *****
    
    TRISBbits.RB0 = 1; // Set RB0 as input
    ANSELHbits.ANS12 = 0; // Digital input buffer of RB0 is enabled (pin 21 = RB0 = AN12 = INT0)
    WPUBbits.WPUB0 = 1; // RB0 pull-up individually enabled

    TRISBbits.RB1 = 1; // Set RB1 as input
    ANSELHbits.ANS10 = 0; // Digital input buffer of RB1 is enabled (pin 22 = RB1 = AN10 = INT1)
    WPUBbits.WPUB1 = 1; // RB1 pull-up individually enabled

    INTCON2bits.nRBPU = 0; // PORTB pull-up global enabled
    
    // ***** Configure Interrupts ***** 
    
    RCONbits.IPEN = 1; // Enable priority levels on interrupts 

    // Configure INT0 interrupt
    INTCONbits.INT0IE = 1; // 1 = Enables the INT0 external interrupt
    INTCON2bits.INTEDG0 = 1; // 1 = Interrupt on rising edge
    INTCONbits.INT0F = 0; // Clear INT0 flag

    // Configure INT1 interrupt
    INTCON3bits.INT1E = 1; // 1 = Enables the INT1 external interrupt
    INTCON3bits.INT1IP = 0; // 0 = Low priority
    INTCON2bits.INTEDG1 = 1; // 1 = Interrupt on rising edge
    INTCON3bits.INT1IF = 0; // Clear INT1 flag
}