/* Exercise 3.4 Delayed debouce test uneven on/off times   */
/* 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


void delay ( int length )
{
    int i, j;

    for ( i = 0 ; i < length ; i++ )        //Loop (length) times
    {
        for ( j = 0 ; j < 10 ; j++ );       //Loop 10 times
    }
}


unsigned char get_debounced_port ( void )
{
    unsigned char count = 0 ;       //Create local variables
    unsigned char oldv, newv ;

    oldv = PORTB & 0x1F;            //Store current state of PORTB pin 0
    while (count < 20)              //Loop while count variable less than 20
    {
        newv = PORTB & 0x1F;        //collect current state of PORTB pin 0
        if (oldv == newv)           //If state matches initial state
        {
            count++ ;               //Increment the count variable
        }
        else
        {
            count = 0 ;             //Reset the count variable
            oldv = newv ;           //Store current state of PORTB pin 0
        }
    }
    return oldv ;                   //If current state and old state match for 20 cycles then return state
}


unsigned int get_move ( void )
{
    unsigned int debouncedport ;
    int i ;

    for ( i = 0 ; i < 100 ; i++ )
    {
        debouncedport = get_debounced_port();

        if (debouncedport != 0x00)        //If somethings been pressed, return it
        {
            return debouncedport;
        }

        delay(300);
    }

    return 0x00 ;       //If we've got here, nothings been pressed so return 0
}


int main (void)
{
    unsigned int move;

    ANSELA = 0x00;                  //Set PORTA to Digital Mode - Defaults to analogue mode
    ANSELB = 0x00;                  //Set PORTB to Digital Mode - Defaults to analogue mode
    OPTION_REG = 0xC0;
    TRISA = 0x00;                   //Set all of PORTA to be configured as an output
    TRISB = 0xFF;                   //Set all of PORTB to be configured as an input

    while (1)                       //Loop forever
    {
        LATA = 0;
        move = get_move();

        if (move == 0x00)
        {
            LATA = 0xFF;
        }
        else
        {
            LATA = move;
        }
        delay(30000);
    }

    return 0;
}