// Exam 2 Problem 3

/**  Header Files **************************************************/
#include <p18f4520.h>
#include <stdio.h>
#include <adc.h>
#include <portb.h>
#include <delays.h>

/** Configuration Bits *********************************************/
#pragma config OSC = INTIO67
#pragma config WDT = OFF
#pragma config LVP = OFF
#pragma config BOREN = OFF
#pragma config XINST = OFF

/** Define Constants Here ******************************************/
#define PRESSED 0

/** Local Function Prototypes **************************************/
void low_isr(void);
void high_isr(void);

/** Declare Interrupt Vector Sections ****************************/
#pragma code high_vector=0x08

void interrupt_at_high_vector(void) {
    _asm goto high_isr _endasm
}

#pragma code low_vector=0x18

void interrupt_at_low_vector(void) {
    _asm goto low_isr _endasm
}

/** Global Variables ***********************************************/
int ledIsOn = 0;

/*******************************************************************
 * Function:        void main(void)
 ********************************************************************/
#pragma code

void main(void) {
    // Set the clock to 4 MHz
    OSCCONbits.IRCF2 = 1;
    OSCCONbits.IRCF1 = 1;
    OSCCONbits.IRCF0 = 0;

    // Pin IO Setup
    OpenADC(ADC_FOSC_8 & ADC_RIGHT_JUST & ADC_12_TAD,
            ADC_CH0 & ADC_INT_OFF & ADC_REF_VDD_VSS,
            0x0B); // Four analog pins
    TRISA = 0xFF; // All of PORTA input
    TRISB = 0xFF; // All of PORTB input
    TRISC = 0x00; // All of PORTC output
    TRISD = 0x00; // All of PORTD output
    PORTC = 0x00; // Turn off all 8 Port C LEDs

    // Interrupt setup
    RCONbits.IPEN = 1; // Put the interrupts into Priority Mode

    OpenRB2INT(PORTB_CHANGE_INT_ON & FALLING_EDGE_INT & PORTB_PULLUPS_OFF);
    INTCON3bits.INT2IP = 0;         // Setting the prior as high here

    INTCONbits.GIEH = 1; // Turn on High Priority interrupts (Priority mode)
    INTCONbits.GIEL = 1; // Turn on Low Priority interrupts (Priority mode)

    while (1) {
    }
}

/*****************************************************************
 * Function:        void high_isr(void)
 ******************************************************************/
#pragma interrupt high_isr

void high_isr(void) {
    // Add code here for the high priority Interrupt Service Routine (ISR)
}

/******************************************************************
 * Function:        void low_isr(void)
 ********************************************************************/
#pragma interruptlow low_isr

void low_isr(void) {
    // Add code here for the low priority Interrupt Service Routine (ISR)
    if (INTCON3bits.INT2IF) { // Interrupt 2, RB2 with debounce
        INTCON3bits.INT2IF = 0;
        Delay1KTCYx(30); // Assumes a 4 MHz clock
        if (PORTBbits.RB2 == PRESSED) {
            if (ledIsOn) {
                ledIsOn = 0;
                PORTCbits.RC0 = 0;
            } else {
                ledIsOn = 1;
                PORTCbits.RC0 = 1;
            }
        }
    }
}