/* Exercise 8.2 Reaction Timer */
/* Created David Miles April 2006 */
/* Updated Ben Rowland Febuary 2014 */

#include <xc.h>

// CONFIG1
#pragma config FOSC = HS        // Oscillator Selection (HS Oscillator, High-speed crystal/resonator connected between OSC1 and OSC2 pins)
#pragma config WDTE = OFF       // Watchdog Timer Enable (WDT disabled)
#pragma config PWRTE = OFF      // Power-up Timer Enable (PWRT disabled)
#pragma config MCLRE = ON       // MCLR Pin Function Select (MCLR/VPP pin function is MCLR)
#pragma config CP = OFF         // Flash Program Memory Code Protection (Program memory code protection is disabled)
#pragma config CPD = OFF        // Data Memory Code Protection (Data memory code protection is disabled)
#pragma config BOREN = ON       // Brown-out Reset Enable (Brown-out Reset enabled)
#pragma config CLKOUTEN = OFF   // Clock Out Enable (CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin)
#pragma config IESO = OFF       // Internal/External Switchover (Internal/External Switchover mode is disabled)
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable (Fail-Safe Clock Monitor is disabled)

// CONFIG2
#pragma config WRT = OFF        // Flash Memory Self-Write Protection (Write protection off)
#pragma config VCAPEN = OFF     // Voltage Regulator Capacitor Enable (All VCAP pin functionality is disabled)
#pragma config PLLEN = OFF      // PLL Enable (4x PLL disabled)
#pragma config STVREN = ON      // Stack Overflow/Underflow Reset Enable (Stack Overflow or Underflow will cause a Reset)
#pragma config BORV = LO        // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (Vbor), low trip point selected.)
#pragma config LVP = OFF        // Low-Voltage Programming Enable (High-voltage on MCLR/VPP must be used for programming)

#define _XTAL_FREQ 19660800	// Defines the hardware crystal frequency allowing the delay function to work correctly

#include "lcdlib.h"

const unsigned char down [5] = {'d','o','w','n',0x00};
const unsigned char up [5]   = {'u','p',' ',' ',0x00};

int time_count = 0 ;
unsigned char counter = 0;


void setup_hardware (void)
{
    ANSELA = 0x00;              //Set PortA to use digital inputs
    ANSELB = 0x00;
    TRISA = 0xFF;               //PORTA set to all inputs
    TRISB = 0x00;               //PORTB set to all outputs

    INTCON = 0b10100000;        //Configure the INTCON register to enable timer interrupts
    OPTION_REG = 0b01000100 ;   //Configure the timer to use the prescaler
}


void tmrHandler( void )
{
    if (PORTA & 0x01)           //increment the timer if the button is held down
    {
        time_count = time_count + 1 ;
    }
}


//This is the interrupt handler It is called when the PICmicro detects an interrupt.
//It checks the status bits to find out who caused the interrupt and then calls that handler
void interrupt isr( void )
{
    if(INTCON & 0b00000100)         //if the timer has overflowed bit 2 of INTCON is set high
    {
        INTCON = INTCON & 0b11111011;          //clear the bit to turn off this interrupt
        counter = counter + 1;
        if ( counter > 2 )
        {
            counter = 0;
            tmrHandler();           //call the handler  function
        }
    }
}



void display_value ( int value )
{
  unsigned char hunds, tens, units ;

  /*  first get the digits  */

  units = value % 10 ;
  value = value / 10 ;
  tens = value % 10 ;
  value = value / 10 ;
  hunds = value % 10 ;

  /*  now display them      */

  lcd_print_ch ( '0' + hunds ) ;
  lcd_print_ch ( '0' + tens ) ;
  lcd_print_ch ( '0' + units ) ;
}



int main (void)
{
    setup_hardware();
    lcd_start();

    while (1)                   //Loop forever
    {
        lcd_cursor(0, 0);

        if (PORTA & 0x01)
        {
            lcd_print(down);
        }
        else
        {
            lcd_print(up);
        }

        display_value (time_count);
    }

    return 0;
}