// PIC18 in C - Versione 0.1 - Luglio 2014
// Copyright (c) 2014, Vincenzo Villa
// Creative Commons | Attribuzione-Condividi allo stesso modo 3.0 Unported.
// Creative Commons | Attribution-Share Alike 3.0 Unported
// https://www.vincenzov.net/tutorial/PIC18/timer0.htm

// Reference: PIC18F14K50 data sheet (note: page as DS41350C printed edition)

#include "configurationsbits.h"
#include <plib.h>

#define _XTAL_FREQ 1000000
#define TIMER0_VALUE 3036 // See text - 0,5 Hz blink

void interrupt __low_priority my_isr_l(void) {
    if (INTCONbits.TMR0IF == 1) // Interrupt from Timer0?
    {
        WriteTimer0(TIMER0_VALUE); // Write a value into the Timer0 registers TMR0L & TMR0H

        LATCbits.LC1 = ~LATCbits.LC1; // Change LEDs status
        INTCONbits.TMR0IF = 0; // Clear interrupt status
    }
}

void main(void) {

    TRISC = 0x00; // Set PORTC as output
    PORTC = 0; // Turn off all LED

    RCONbits.IPEN = 1; // Enable priority levels on interrupts

    OpenTimer0(TIMER_INT_ON & T0_16BIT & T0_SOURCE_INT & T0_EDGE_FALL & T0_PS_1_4);
    WriteTimer0(TIMER0_VALUE); // Write a value into the Timer0 registers TMR0L & TMR0H

    INTCON2bits.TMR0IP = 0; // Set low priority interrupt

    INTCONbits.GIEL = 1; // Enables all low priority interrupts

    ei(); // Global enable interrupt

    while (1) { // 5 Hz LED blink, forever
        LATCbits.LC0 = ~LATCbits.LC0;
        __delay_ms(100);
    }
}