// Exam 2 Problem 2

/**  Header Files **************************************************/
#include <p18f4520.h>
#include <stdio.h>
#include <adc.h>
#include "LCD Module.h"
#include <timers.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 ******************************************/
// = 2^16 - 0.75/0.000016
#define START_TIMER 18661

/** Local Function Prototypes **************************************/
void low_isr(void);
void high_isr(void);
void updateLcd(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 counts = 0;
char line1[17]; // LCD variables
char line2[17];

/*******************************************************************
 * 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

    XLCDInit();
    XLCDClear();
    updateLcd();

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

    OpenTimer0(TIMER_INT_ON & T0_16BIT & T0_SOURCE_INT & T0_PS_1_16);
    INTCON2bits.TMR0IP = 1; // Confirm high priority (the default)

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

    WriteTimer0(START_TIMER);

    while (1) {
        // Note, you could also choose to do the updateLcd here instead
        // and remove it from that other places.
//        updateLcd();
    }
}

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

void high_isr(void) {
    // Add code here for the high priority Interrupt Service Routine (ISR)
    if (INTCONbits.TMR0IF) { // Timer 0 interrupt
        INTCONbits.TMR0IF = 0;
        WriteTimer0(START_TIMER);
        counts++;
        updateLcd();
    }

}

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

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

#pragma code

/*****************************************************************
 * Additional Helper Functions
 ******************************************************************/

void updateLcd() {
    sprintf(line2, "%d counts     ", counts);
    XLCDL2home();
    XLCDPutRamString(line2);
}