void calc_distance(void)
{
unsigned int mathKeep;		// used for voltage calculations backup
	// from the transeiver datasheet the analog voltage is
	// the inverse of distance, so distance can be calculated
	// d = (1 / volts) then just scaled to suit the transeiver

	// load ADC value in 16bit math var
	math = ADRESH;
	math = (math * 256);
	math += ADRESL;

	// now invert it; (1 / volts) use (6050 / volts) for scaling
	math = (6050 / math);
	if(math >= 2) math -=2;		// fix linear error (-2)
	if(math > 99) math = 99;	// max limit at 99cm

	//Create a copy of math for more use
	mathKeep = math;
    //LiquidLevel=height-;	

	// convert from 0-99 to 2 decimal digits, 0-99cm
	cm10=0;
	while(math >= 10)
	{
		cm10++;
		math -= 10;
	}
	cm = math;

	math = mathKeep;	//Now our original data is back and can be used.
}

typdef struct filter_type
{
   Uint16 accumulator;
   Uint16 output;
   Uint8 shift_value;
   Uint8 initialized;
};

filter_type adc_filter;

void Init_Filter( filter_type *filter, Uint8 shift )
{
   filter->initialized = FALSE;
   filter->shift_value = shift;
}

void Update_Filter( filter_type *filter, Uint16 new_value )
{
   if (filter->initialized != TRUE)
   {
      filter->output = new_value;
      filter->accumulator = new_value << filter->shift_value;
      filter->initialized = TRUE;
   }
   else
   {
      filter->accumulator -= filter->output;
      filter->accumulator += new_value;
      filter->output = filter->accumulator >> filter->shift_value;
   }
}

#include <pic.h>
#include "pic.h"
#include "delay.h"
#include "math.h" 
#include <stdio.h>
#include <stdlib.h>	//

void userMenu(char pos); //  
void FloatToStr(float , char[]); 
void DelayMs(unsigned char);
void lcd_cmd(unsigned char);
void lcd_data(unsigned char); 
void lcd_clear(void);
void lcd_puts(const char[]);
void lcd_goto_L1(void);
void lcd_goto_L2(void);
void lcd_cursor(unsigned char);
void lcd_init(void);
void init(void);
char WaitForInput(char expire);  
unsigned char user_input(void);
void home_screen(void);
void EnterHeight(void);
void EnterScreen(void);
void ShowDigits(unsigned char val);
void calc_distance(void);
void main(void);


unsigned char cm2LCD;
unsigned char posneg;
unsigned char LLHigh, LLLow;
unsigned int LiquidLevel;


      

#define LCD_RS RC0		//LCD RS pin
#define LCD_EN RC1		//LCD EN pin
#define LCD_STROBE()	LCD_EN = 1; asm("nop"); asm("nop"); LCD_EN = 0

unsigned char cm10;		//
unsigned char cm;		//
unsigned int math;		// used for voltage calculations


unsigned char NumDec;
unsigned char NumSep[2];
   
unsigned char i,j,k;
//char temp[8];
//[/b]
unsigned char height=50;
unsigned char range;
unsigned char area;
unsigned char SensorPos=10;
//[/b] New Vars
char input_sw;

  
char mnuPOS;

unsigned char MyVal;
unsigned char MyValLCD[2];
unsigned char MyMaxVal;
unsigned char MyMinVal;
unsigned long bres;		// for bresenham 2-second timer system

unsigned char ;

#define HOME_SW RC2				//HOME switch	
#define INCREASE_SW RC3			//INCREASE switch
#define DECREASE_SW RC4			//DECREASE switch
#define ENTERSETTINGS_SW RA4	//ENTERSETTINGS switch



///////////////////////CONVERT FLOAT TO STRING///////////////////
// This function was taken from the CAVR library. It was modified slightly
// to suit our design.
void FloatToStr(float n, char str[])
{
float scale;
unsigned char d,f;
f=0;i=0;
if (n<0.0) {n=-n; str[f]='-'; f++;}; 
n=n+0.005;
scale=1.0;
while (n>=scale) {scale=scale*10.0; ++i;};
if (i==0) {str[f]='0'; f++;}
else
while (i--)
	  {
      scale=floor(0.5+scale/10.0);
      d=(unsigned char) (n/scale);
      str[f]=d+'0';
      n=n-scale*d;
	  f++;
      };

str[f]='.';
f++;
for (j=0;j<=1;j++) //2 decimal points
      {
      n=n*10.0;
      d=(unsigned char) n;
      str[f]=d+'0';
      n=n-d;
	  f++;
	  };
str[f]='\0';
}
///////////////////END CONVERT FLOAT TO STRING///////////////////

/////////////////////////////DELAY///////////////////////////////
void DelayMs(unsigned char cnt)
{
#if	XTAL_FREQ <= 2MHZ
	do {
		DelayUs(996);
	} while(--cnt);
#endif

#if    XTAL_FREQ > 2MHZ	
	unsigned char	p;
	do {
		p = 4;
		do { 
			DelayUs(250);
		} while(--p);  
	} while(--cnt);
#endif
}

void DelayS(unsigned char cnt)
{
	for (j=0; j<(cnt*10); j++)
		DelayMs(100);
}
///////////////////////////DELAY END/////////////////////////////

//////////////////////////////LCD SETUP//////////////////////////
/* send a command to the LCD */
void lcd_cmd(unsigned char c)
{
	DelayMs(2); //wait for LCD to be ready shorter delay 
	LCD_RS = 0;	 //write instruction
	PORTB = (c & 0xF0); //load upper nibble on LCD data lines
	LCD_STROBE(); //send instruction to LCD
	PORTB = ((c << 4) & 0xF0); //load upper nibble on LCD data lines
	LCD_STROBE(); //send instruction to LCD   	
}

/* send data to the LCD */
void lcd_data(unsigned char c)
{
	DelayMs(2); //wait for LCD to be ready shorter delay 
	PORTB = 0x00;
	LCD_RS = 1; //write data
    PORTB |= (c & 0xF0); //load upper nibble on LCD data lines     
	LCD_STROBE(); //send instruction to LCD
	PORTB &= 0x00; //load upper nibble on LCD data lines
	PORTB |= ( (c << 4) & 0xF0); 
	LCD_STROBE(); //send instruction to LCD
}

/*Clear the LCD*/
void lcd_clear(void)
{
	lcd_cmd(0x01); //command to clear LCD
}

/*write a string of chars to the LCD*/
void lcd_puts(const char s[])
{
	j = -1;
	while(s[++j]!=('\0')) // send characters until null character reached
		lcd_data(s[j]);
}

/*go to beginning of line 1*/
void lcd_goto_L1(void)
{
	lcd_cmd(0b10000000); // command to go to line 1
}

/*go to beginning of line 2*/
void lcd_goto_L2(void)
{
	lcd_cmd(0b11000000); // command to go to line 2
}

/*move cursor "x" positions to the right*/
void lcd_cursor(unsigned char x)
{
	lcd_cmd(((x)&0x7F)|0x80); 
}

/*initialise the LCD - put into 4 bit mode*/
void lcd_init(void)
{
	LCD_RS = 0;	
	LCD_EN = 0;
	DelayMs(20); //wait for LCD startup
	lcd_cmd(0x02);
 
	lcd_cmd(0x28);	// 4-bit mode
	lcd_cmd(0x08);	// display off
	lcd_cmd(0x01);	// clear display
	lcd_cmd(0x0C);	// disp. on, cursor off, cursor blink off
	lcd_cmd(0x06);	// entry mode
	lcd_cmd(0x80);  // initialise DDRAM address to zero
}
//////////////////////////LCD SETUP END//////////////////////////
    

void init(void)
{   
	
	// setup the PIC 16f690
	OSCCON = 0x72;      	// internal osc, 8MHz


	PORTA = 0;
	TRISA = 0b10010010; 	// RA7 high imp, RA3 is serial out, RA4 button input 


	
 	PORTB = 0;          	// PORTB not used
    WPUB = 1;				// PORTB pullups ON		
    RABPU = 0;


    /* Init ADC */
    ADCON0 = 0b10000101;	// bit 7 right justify,analogue channel select bits bits5-2  0001=AN1,ADC ON, RA1 is ADC input
	ADCON1 = 0b00100000;	//bits6-4  fosc/32
    ADON=1;	                // turn on the A2D conversion module

	
	ANSEL=0x02;            //set RA1 as analog input for GP2 sensor
	ANSELH=0x00;

    T1CON = 0b00010001;     // TMR1 is ON, 1:2 prescale, =1MHz
	T2CON = 0b00000101;     // TMR2 is ON, 1:4 prescale, =1MHz



	MyVal = 0; //initializn these variables here
	MyMinVal = 0;
	MyMaxVal = 99;
  
	TRISB=0x00; 
	TRISC=0xFC;
    
	lcd_init(); //call LCD initialisation

}
//EDITED this a bit. now if expire input is set it will leave loop with a 0
//instead of rechecking this will be useful for display your measured data and 
//waiting for user to exit.
char WaitForInput(char expire){
char done;
char temp;
done = 0;
temp = 0;
while(!done){
    if(!ENTERSETTINGS_SW){
		while(ENTERSETTINGS_SW);
        temp = 1;
        done = 0xff;
    }

    if(!HOME_SW){
		while(HOME_SW);
        temp = 2;
        done = 0xff;
    }

    if(!INCREASE_SW){
		while(INCREASE_SW);
        temp = 3;
        done = 0xff;
    }

    if(!DECREASE_SW){
		while(DECREASE_SW);
        temp = 4;
        done = 0xff;
    }
	if(expire == 1) break;
}//end of while
    DelayMs(150);    //debounce
    return temp;
}//
void userMenu(char pos){
    unsigned int delaytime = 100000; // 100ms CHANGE THIS FOR YOUR BELOW DELAY 
	lcd_clear();
	lcd_goto_L1();

	switch(pos){
		case 0:
			lcd_puts("    HEIGHT    ");
			break;		
		case 1:
			lcd_puts("    RANGE     ");
			break;		
		case 2:
			lcd_puts(" SURFACE AREA ");
			break;							//
		case 3: 
			lcd_puts("   MEASURED   ");
			 while(WaitForInput(1) != 2){		//Wait for user to press enter to leave loop

 				// wait for 2 seconds, uses TMR1 free running at 1Mhz
   				while(!TMR1IF)  		// wait for TMR1 overflow
				TMR1IF = 0; 			// clear overflow flag

				bres += 65536;			// add 65536uS to bres value
				if(bres >= delaytime )		// if reached 2 seconds!
	 			{
    				bres -= delaytime ;	// subtract 2 seconds, keep error 
		  	
					// read the ADC voltage RA1 (Sharp GP2 sensor)
					GODONE=1;					// initiate conversion on the channel 0
					while(GODONE) continue;  	// Wait convertion done
					calc_distance();			// convert ADC value to distance

					lcd_goto_L2();				//Only change line 2
//
					if(posneg == 'p')
						lcd_data('+');
					else
						lcd_data('-');
//
					lcd_data(LLHigh);
					lcd_data(LLLow);
	    			lcd_puts(" [cm] ");			//comment this out if you want
			   } 
		} 
		lcd_goto_L1();
		lcd_puts(" Loading Home ");
		lcd_goto_L2();
		lcd_puts("              ");
		DelayS(1);
		break;
	}

	if(pos == 3) return;
	lcd_goto_L2();
	lcd_puts("Press Up/Down"); //home screen message (line 2)
}

// New Menu System
void EnterHeight(void){
	lcd_clear();
	lcd_goto_L1();
	lcd_puts(" ENTER HEIGHT ");
	lcd_goto_L2();
	lcd_puts("Press Up/Down"); //home screen message (line 2)
}

void EnterScreen(void){
	lcd_clear();
	lcd_goto_L1();
	lcd_puts(" [cm] ");
}

void ShowDigits(unsigned char val){

    MyValLCD[0] = val /10;    //returns the quotient (if temp = 35 the result is 3)
    MyValLCD[1] = val % 10; 	//Returns remainder   (if temp = 35 the result is 5)

	MyValLCD[0] += 0x30;	//to ASCII
	MyValLCD[1] += 0x30;	//to ASCII

	EnterScreen();
	lcd_goto_L2();
	lcd_data(MyValLCD[0]);	//to LCD
	lcd_data(MyValLCD[1]);  //to LCD
}

  
void calc_distance(void)
{
	unsigned int tmp;
unsigned int mathKeep;		// used for voltage calculations backup
	// from the transeiver datasheet the analog voltage is
	// the inverse of distance, so distance can be calculated
	// d = (1 / volts) then just scaled to suit the transeiver

	// load ADC value in 16bit math var
	math = ADRESH;
	math = (math * 256);
	math += ADRESL;

	// now invert it; (1 / volts) use (6050 / volts) for scaling
	math = (6050 / math);
	if(math >= 2) math -=2;		// fix linear error (-2)
	if(math > 99) math = 99;	// max limit at 99cm

	//Create a copy of math for more use
	mathKeep = math;
    //LiquidLevel=height-;	

	// convert from 0-99 to 2 decimal digits, 0-99cm
	cm10=0;
	while(math >= 10)
	{
		cm10++;
		math -= 10;
	}
	cm = math;

	math = mathKeep;	//Now our original data is back and can be used.
	//This will check if negative
	LiquidLevel=height-math;	

//
	posneg = 'p';
        if((LiquidLevel < 0) || (LiquidLevel > 0xFF00)){
		LiquidLevel = -LiquidLevel ;
		posneg = 'n';
	}
//
	//if below zero which will be in the 0xFFFF range i just chose any 0xFFxx number :D
      //LiquidLevel is higher than 09 so spilt the variable LiquidLevel into 2 //
      LLHigh = ( LiquidLevel / 10 ) + '0'; // 
      LLLow = ( LiquidLevel % 10 ) + '0';  // 
      


}
 //
unsigned char user_input(void)		//This will return what we want
{
	char done = 0;
 
	MyVal = 0;			//Start on 0
	while(done == 0){
   	  input_sw = WaitForInput(0);
		
      switch(input_sw){
		case 1:
			done = 0xff; 			//This tells us the user finished entering
			lcd_goto_L1();
			lcd_puts("      OK       "); //home screen message (line 1)
			break;
      	case 3:
			if(MyVal < MyMaxVal)
      			MyVal++;
			EnterScreen();
			ShowDigits(MyVal);
			break;
      	case 4:
			if(MyVal > MyMinVal)
      			MyVal--;
			EnterScreen();
			ShowDigits(MyVal);
        	break;
		default: 
			break;
      }
	  
	}
	DelayMs(250);
	DelayMs(250);
	return MyVal;
}

void home_screen(void){
	mnuPOS = 0;
	lcd_clear();
	lcd_goto_L1();
	lcd_puts("INFRARED LIQUID"); //home screen message (line 1)
	lcd_goto_L2();
	lcd_puts("LEVEL DETECTOR"); //home screen message (line 2)
  
	input_sw = 0;			//Reset the value

	while(input_sw != 1)  	//Wait until enter is pressed
		input_sw = WaitForInput(0);

	userMenu(0);
	DelayMs(2);				//shorter delay 
    height = user_input();	//The HEIGHT var will have the myVal

	userMenu(1);
	DelayMs(2);				//shorter delay 
    range = user_input();	//The HEIGHT var will have the myVal

	userMenu(2);
	DelayMs(2);				//shorter delay 
    area = user_input();	//The HEIGHT var will have the myVal
//
	userMenu(3);
	DelayMs(2);				//shorter delay 
	input_sw = 0;			//Reset the value

//Waits for user to press ENTER to show home screen
/*
"enter height"
call enter/settings (which is now user input function in new code)
height=MyVal

"enter range"
call user_input
range=MyVal

"enter surface area"
call user_input
area=MyVal
*/
}
  
//*********************************************************
/*  Junebug_Serial4.c    RomanBlack.com 19th July 2009.

    uses "zero error 1 second timer"
	system to generate a 2 second interval, then every
	2 seconds it reads an analog voltage from a
	Sharp GP2 distance sensor and converts it to decimal
	distance, then sends that data to a LCD

	Code for MikroC, config handled by MikroC compiler;
	_INTI02_OSC_1H
	_WDT_OFF_2H
	-MCLRE_ON_3H
	_LVP_OFF_4L 
	_PWRT_ON_2L
*/
//*********************************************************

void main(void)
{  
    init();	// initialise I/O ports, LCD
    while(1){
 	home_screen();

 /*// wait for 2 seconds, uses TMR1 free running at 1Mhz
   	while(!TMR1IF)  // wait for TMR1 overflow
	TMR1IF = 0; 	// clear overflow flag

	bres += 65536;			// add 65536uS to bres value
	if(bres >= 2000000)		// if reached 2 seconds!
	 {
    	bres -= 2000000;	// subtract 2 seconds, keep error
		  	
		// read the ADC voltage RA1 (Sharp GP2 sensor)
		GODONE=1;	// initiate conversion on the channel 0
		while(GODONE) continue;  // Wait convertion done
		calc_distance();		// convert ADC value to distance
	//	LiquidLevel=height-;
	//	lcd_clear();                // Using the new menu you can erase or
	//	lcd_data(cm10 + '0');
	//	lcd_data(cm + '0');
	 //   lcd_goto_L2(); 
	   // lcd_puts("[cm] ");			//comment this out if you want
*/
 
      
        
             
 
   } 
}

	// now invert it; (1 / volts) use (6050 / volts) for scaling
	math = (6050 / math);
	if(math >= 2) math -=2;		// fix linear error (-2)
	if(math > 99) math = 99;	// max limit at 99cm