#pragma config OSC=INTIO2, WDT=OFF, DEBUG=ON
#include <p18F1330.h>
#include <delays.h>
#define LED PORTBbits.RB0       //Define LED as pin 8
#define PIEZO PORTAbits.AN2     //Define PIEZO as pin 6
#define SWITCH PORTAbits.RA0    //Define SWITCH as pin 1
unsigned int knock;
unsigned char x;
unsigned char T;                //Time variable
unsigned char start;            //Knock started?
unsigned char stop;             //Knock stopped?
unsigned char ProgramStart;     //Programming knock started?
unsigned char ProgramStop;      //Programming knock stopped?
unsigned int KnockNumber;       //Number of knocks
unsigned int ProgramNumber;     //Number of programmed knocks
int KnockPattern[KnockNumber];          //Knock time array
int ProgrammedPattern[ProgramNumber];   //Program knock time array

/* Program secret knock */

void program_knock(void)
{
    T=0;
    while(knock!=1)             //While no knock is detected...
    {
        if(ProgramStart==1)         //...if program pattern has started...
        {
            T=T+1;                      //...Time variable counts up
        }
        else if(ProgramStart==0)    //If program pattern has not started...
        {
            Nop();                      //...don't do anything
        }
    }
    ProgrammedPattern[ProgramNumber]=T; //Send time value to program pattern array
}

/* Record timing between knocks */

void record_timing(void)
{
    T=0;
    while(knock!=1)             //While no knock is detected...
    {
        if(start==1)                //...if pattern has started...
        {
            T=T+1;                      //...Time variable counts up
        }
        else if(start==0)           //If pattern has not started...
        {
            Nop();                      //...don't do anything
        }
    }
    KnockPattern[KnockNumber]=T;    //Send Time value to knock array
}

void main(void)
{
    TRISA=0b00000100;
    TRISB=0b00000000;
    ADCON1=0b00001011;          //Pin 6 (piezo) analog, others digital
    knock=0;                    //Initialize variables
    start=0;
    stop=0;
    KnockNumber=0;

    while(1)
    {
        if(SWITCH==1)           //Check if we're programming
        {
            LED=1;                  //If so, turn on LED...
            program_knock();        //...call programming function...
            LED=0;                  //...then turn off LED
        }
        else                    //If we're not programming...
        {
            if(0<PIEZO<3)           //...wait for first knock
            {
                Nop();
            }
            else if (100>PIEZO>3)   //When first knock is detected...
            {
                KnockNumber=KnockNumber+1;      //increase number of sensed knocks
                start=1;                        //Knock has started
                knock=1;                        //Single knock in progress
                LED=1;                          //Flash LED to signify knock detection
                Delay10KTCYx(20);
                LED=0;
                knock=0;                        //Single knock ended
                record_timing();                //Call timing function
            }
        }
    }
}