#if defined(__XC)
    #include <xc.h>         /* XC8 General Include File */
#elif defined(HI_TECH_C)
    #include <htc.h>        /* HiTech General Include File */
#endif

#include <stdint.h>        /* For uint8_t definition */
#include <stdbool.h>       /* For true/false definition */
#include "system.h"        /* System funct/params, like osc/peripheral config */

uint8_t phase = 0xFF;  //Force motor off by phase out of half-wave duration

//void interrupt isr(void)
void __interrupt () ISR (void) {
    /* Determine which flag generated the interrupt and handle it */
   
    // RB0/ExtINT interrupt
    if(INTCONbits.INTF) {
        INTCONbits.INTF = 0; /* Clear Interrupt Flag */
       
        //Edge found. Switch to find next edge
        if (OPTION_REGbits.INTEDG) { //Rising edge found
            OPTION_REGbits.INTEDG = 0; //Now will wait for falling edge
        }
        else { //Falling edge found
            OPTION_REGbits.INTEDG = 1; //Now will wait for rising edge
        }
       
        PR2 = phase;         //Set TRIAC turn-on delay
        TMR2 = 0;            //Reset Timer2 state
        PIR1bits.TMR2IF = 0; //Clear pending Timer2 IF
        PORTBbits.RB4 = 1;   //Disable TRIAC (force pin state)
    }
   
    //Timer2 PR2 match interrupt
    if (PIR1bits.TMR2IF) {
        PIR1bits.TMR2IF = 0;  /* Clear Interrupt Flag */
       
        if (PORTBbits.RB4 == 1) { //Triac pin is OFF
            PORTBbits.RB4 = 0;  //Set TRIAC ON
            PR2 = 0x0A;         //TRIAC on set for 10 * 64us = 0.64ms, next Timer2 interrupt will turn TRIAC pin OFF
        }
        else {
            PORTBbits.RB4 = 1;  //Set TRIAC OFF
            PR2 = 0xFF;         //PR2 should be set by edge, wait for sync.
        }
        TMR2 = 0;               //Reset Timer2 state
    }
}

void main(void) {
    /* Initialize I/O and Peripherals for application */
    PORTA = 0x04; //Turn off LED RA2
    PORTB = 0x10; //Turn off TRIAC RB4
    TRISA = 0x01; //RA0/AN0 - ADC input, RA2... outputs
    TRISB = 0x0F; //RB0-RB3 inputs, RB4... outputs
    OPTION_REG = 0x00; // RB0-interrupt on falling edge initially, Timer0/WDT not used
   
    T1CON = 0x00; // Timer1 Fosc/4 clock; 1:1 prescale, Timer1 disabled
    T2CON = 0x1F; // Timer2 Fosc/4 clock; 1:16 prescale, 1:4 postscaler, Timer2 enabled -- 4Mhz/16 = 62.5kHz = 16us/timer tick
   
    // PR2 will set TMR2IE interrupt period as: PR2 * 4 * 16us
    // For 50Hz 10ms half-period time, we can use values 0-156 as phase delay.
   
    ADCON0 = 0xC0; // Use internal ADC RC oscillator, use AN0 input, ADC disabled (ADON=0)
    ADCON1 = 0x04; // Vref=VDD, AN0,AN1,AN3 - as analog inputs (RA2 - LED)
   
    PIR1 = 0; //Clear pending interrupt flags
    PIE1 = 0x02; //Enable TMR2IE (PR2 matched) interrupt
   
    INTCON = 0xD0; //Enable GIE (global interrupts) + PEIE (peripheral interrupts) + INTE (RB0/Ext INT)

    while(1) {
        phase = 0x75;  // phase = 117;  -- 7.5ms TRIAC phase delay, 25% of power.
    }
}