// 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/timer1.htm

// Reference: PIC18F14K50 data sheet

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

#define _XTAL_FREQ 1000000 // Default PIC18F14K50 clock

#define TIMER1_VALUE 1000 // T1 count from 0 to 1000
#define TIMER0_VALUE 64000 // T0 count from 64000 to 65536 

#define RED LATCbits.LC0 // Output #1 - main code
#define BLUE LATCbits.LC1 // Output #2 - my_isr_low
#define GREEN LATCbits.LC2 // Output #3 - my_isr_high

void interrupt __low_priority my_isr_low(void) {
    if (INTCONbits.TMR0IF == 1) // Interrupt from Timer0?
    {
        WriteTimer0(TIMER0_VALUE); // Set T0 starting value
        for (unsigned char i = 0; i < 50; i++)
            BLUE = ~BLUE; // Change RC1 pin status
        INTCONbits.TMR0IF = 0; // Clear interrupt status
    }
}

void interrupt __high_priority my_isr_high(void) {
    if (PIR1bits.CCP1IF == 1) // Interrupt from Timer1?
    {
        for (unsigned char i = 0; i < 10; i++)
            GREEN = ~GREEN; // Change RC2 pin status
        PIR1bits.CCP1IF = 0; // Clear interrupt status
    }
}

void main(void) {

    TRISC = 0x00; // Set PORTC as output

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

    OpenTimer0(TIMER_INT_ON & T0_16BIT & T0_SOURCE_INT & T0_EDGE_FALL & T0_PS_1_1);
    // Enable T0: interrupt, 16 bit, internal clock
    INTCON2bits.TMR0IP = 0; // Set low priority interrupt
    WriteTimer0(TIMER0_VALUE); // Set T0 starting value

    OpenTimer1(TIMER_INT_OFF & T1_16BIT_RW & T1_SOURCE_INT & T1_PS_1_1);
    // Enable T1: internal clock, no interrupt
    IPR1bits.TMR1IP = 1; // TMR1 Overflow Interrupt Priority set to high

    OpenCompare1(COM_INT_ON & COM_TRIG_SEVNT, TIMER1_VALUE);
    // Enable CCP as compare: at trigger -> interrupt + Timer1 clear
    T3CONbits.T3CCP1 = 0; // Timer1 is the clock source for compare/capture of ECCP1
    IPR1bits.CCP1IP = 1; // CCP1 Interrupt Priority set to high

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

    while (1) {
        RED = ~RED; // Change RC0 pin status
    }
}