#include <Mega32.h>
#include "touch.h"
#include "sed1335.h"

#define TOUCH_enable    0
#define TOUCH_disable   1

#define SPI_WRITE(a)    (SPDR = a)
#define SPI_CS(a)       ((a==1)?(PORTB |=0x10):(PORTB &= ~0x10))
#define SPI_BUSY        ((SPSR & 0x80) == 0)
 
#define DCLK(a)     ((a==1)?(PORTB|=_BV(7)):(PORTB&=(~_BV(7))))
#define DOUT(a)     ((a==1)?(PORTB|=_BV(6)):(PORTB&=(~_BV(6))))
#define DIN		    (PINB&0b00100000)

#define X		    0b11011000
#define Y		    0b10011000

#define TOUCH_INT_DIR       DDRD            
#define TOUCH_PEN1(a)       ((a==1)?(PORTD|=_BV(3)):(PORTD&=(~_BV(3))))
//#define TOUCH_DOWN          (0b0000000100 - (PIND&0b00000100))


void TOUCH_init (void)
{
    //initialize PORT for SPI
    DDRB = 0b10110000;
    PORTB = 0x00;
    //SPI enable, MSB first, master mode, SCK low when idle, sample on leading edge, CLK = f/16=1Mhz
    SPCR = 0b01010010;
    //Clear interrupt flag, clear collision flag, single speed operation  
    SPSR = 0x00;
    
    // set up external interrupt on PD2 (0)
    TOUCH_INT_DIR = 0b11111000; 
    
    TOUCH_PEN1(1);
}

unsigned char TOUCH_get (unsigned char axis)
{
    unsigned int data;

	SPI_CS(TOUCH_enable);
	SPI_WRITE(axis);
    while(SPI_BUSY);
    
    SPI_WRITE(0x00);
    while(SPI_BUSY);
    
    return (SPDR << 1);
}        

struct Point TOUCH_coord;

struct Point* TOUCH_get_coord ()
{
    unsigned char i;
         
    TOUCH_PEN1(0);
    
	TOUCH_coord.x = TOUCH_get(X);
	
	if (TOUCH_coord.x == 0)       // no touch, return out of bounds
	{
        TOUCH_coord.x = OOB;
        TOUCH_coord.y = OOB;
        return &TOUCH_coord; 
    }
    
    // get y coord
	TOUCH_coord.y = TOUCH_get(Y);
	
	TOUCH_PEN1(1);
	
	// get 7 more values and average
	for (i=0; i<7; i++)
	{
	    TOUCH_PEN1(0);
	    TOUCH_coord.x += TOUCH_get(X);
	    TOUCH_coord.y += TOUCH_get(Y);
	    TOUCH_PEN1(1);
	}
	                                   
	// average the values (div by 8)
	TOUCH_coord.x = TOUCH_coord.x >> 3;
	TOUCH_coord.y = TOUCH_coord.y >> 3; 
	
	//return &coord;

	// scale coordinates to the screen

	if ( (TOUCH_coord.x >= 12) && (TOUCH_coord.x <= 222) )
	{
		TOUCH_coord.x = (unsigned short)((float)(TOUCH_coord.x - 12) * 1.52);
	}
	else
	{
		TOUCH_coord.x = OOB;		// out of bounds
	}

	if ( (TOUCH_coord.y >= 12) && (TOUCH_coord.y < 240) )
	{
		TOUCH_coord.y = (unsigned short)(240 - ((float)(TOUCH_coord.y - 12) * 1.12));
	}
	else
	{
		TOUCH_coord.y = OOB;
	}
	return &TOUCH_coord;
}