/**************************************************************************************************
*	  		    ADS7843 touch screen Driver
* File name     : touch.h
* Programmer    : jaruwit supa
* Web presence  : www.circuitidea.com
* Note          : BL-TFT240320PLUS using ADS7843 driver
* Language      : avrGCC
* Hardware      : arduino
* Date          : 20/12/2009
************************************************************************************************
* DESCRIPTION
* ===========
	BL-TFT240320PLUS contain touch screen ADS7843.
driver touch screen using 10 bit(1024) to calibrate(not include in api)
Calibrate routine use for calibrate and save matrix to eeprom. 
touch screenclass wil read back on init class.
Change eeprom location by change #define EE_MATRIX_ADDR

Because of no hardware PENIRQ so lowest point require for test touch press or not.
Change #define ADC_MIN_Y for untouch condition. becare full 10 bit(1024) is base.

************************************************************************************************/

/* _____STANDARD INCLUDES____________________________________________________ */
extern "C"
{
	#include <inttypes.h>
	#include <avr/io.h>
	#include <avr/eeprom.h>
}

/* _____PROJECT INCLUDES_____________________________________________________ */
#include "WProgram.h"
#include "touch.h"

/* _____PRIVATE DEFINES______________________________________________________ */
#define ADC_MIN_Y	(100) // Modified, orig 100

/* _____HARDWARE DEFINES_____________________________________________________ */
#define TS_SPI_DDR  DDRB
#define TS_SPI_PORT PORTB
#define TS_SPI_PIN  PINB

#define TS_SS_BIT	2
#define TS_MOSI_BIT	3
#define TS_MISO_BIT	4
#define TS_SCK_BIT	5

#define TS_CS_DDR  DDRB
#define TS_CS_PORT PORTB
#define TS_CS_PIN PINB
#define TS_CS_BIT 1


/* _____Constructor__________________________________________________________ */

touchscreen::touchscreen()
{
	getMatrix();
}

/* _____Private _____________________________________________________________ */
unsigned char touchscreen::readADC(unsigned char axis)
{
	SPDR = axis;				// transfer axis
	while((SPSR & 0x80) == 0);	// wait for complete
	return (SPDR);				// get data
}    

void touchscreen::readTouch(POINT * pADC_point)
{
    unsigned int x,y;
	unsigned char buf_data[4];

	// enable touch screen 
	TS_CS_PORT	&= ~(1<<TS_CS_BIT);	// Enable CS

	buf_data[2] = readADC(0x94);	//Write Command Measure Y-Position ; 
	buf_data[2] = readADC(0x00);	//Read ADC data X-Position (7-bit byte High) data: 0ddddddd	(bit11-bit5)
	buf_data[3] = readADC(0x00);	//Read ADC data Y-Position(5-bit byte Low)  data: ddddd000 (bit)
	buf_data[0] = readADC(0xD4);	//Write Command Measure X-Position
	buf_data[0] = readADC(0x00);	//Read ADC data X-Position (7-bit byte High) data: 0ddddddd	(bit11-bit5)
	buf_data[1] = readADC(0x00);	//Read ADC data X-Position (5-bit byte Low)  data:ddddd000(bit)

	// disable touch screen
	TS_CS_PORT	|= (1<<TS_CS_BIT);	// Disable CS

	x  = (unsigned int)buf_data[0] << 5;	// Shift 7 bit High
	x |= (unsigned int)buf_data[1] >> 3;	// Shift 5 bit low

	y  = (unsigned int)buf_data[2] << 5;   	// Shift 7 bit High
	y |= (unsigned int)buf_data[3] >> 3;   	// Shift 5 bit low

	// using 10 bit for 3 point calibrate. by integrate 4 point(0,1,2,3) in to 1 point
	pADC_point->x = x >> 2;				// Modified orig 2
	pADC_point->y = (4095L-y) >> 2;			//	"
}

void touchscreen::sampling(POINT * pScreen, unsigned char nTest)
{
	POINT adcPoint;

	long avgX, avgY;
    
	unsigned char i;				// scan counter
	unsigned char nInvalid;			// Invalid counter
    
	pScreen->x = 0;
    	pScreen->y = 0;
   
	readTouch(&adcPoint);			// Read value ADC Touch X-Y
	if (adcPoint.y < ADC_MIN_Y) 	// inactive touch
		return;

	avgX = adcPoint.x;
	avgY = adcPoint.y;

    nInvalid = 0;
    i = nTest;
    do
	{
        if (++nInvalid > 20)			// too many error. touch not long enought 
        	return;
            
    	readTouch(&adcPoint);			// Read value ADC Touch X-Y
    	if (adcPoint.y < ADC_MIN_Y)		// inactive touch
        	continue;

		// average with 
		avgX += adcPoint.x;
		avgX >>= 1;
		avgY += adcPoint.y;
		avgY >>= 1;

        nInvalid = 0;						// reset invalid
    } while (--i);

    pScreen->x = avgX;
    pScreen->y = avgY;
}

/* _____Public _______________________________________________________________ */
void touchscreen::Reset(void)
{
    char temp;

	// init port
	TS_CS_PORT	|= (1<<TS_CS_BIT);						// Disable CS
	TS_CS_DDR	|= (1<<TS_CS_BIT);						// Turns on CS pin as output

	TS_SPI_DDR	|= (1<<TS_SCK_BIT)|(1<<TS_MOSI_BIT);
	 if (!(TS_SPI_DDR & (1<<TS_SS_BIT)))					// if SS is input
	    	TS_SPI_PORT |= (1<<TS_SS_BIT);					//   set internal pull up SS for spi master mode
	TS_SPI_PORT	|= (1<<TS_MISO_BIT);					// internal pull up MISO

	// init spi master
	SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR1)|(1<<SPR0);				// Initialize SPI port (Mode 0) | /128clock
	temp = SPSR;								// Clear interrupt flag
}    

void touchscreen::getMatrix(void)
{
	eeprom_read_block((void*)&matrix, (const void*)EE_MATRIX_ADDR, sizeof(MATRIX));
}

void touchscreen::setMatrix(void)
{
	eeprom_write_block((const void*)&matrix, (void*)EE_MATRIX_ADDR, sizeof(MATRIX));
}

void touchscreen::readPoint(void)
{
	sampling(&screenPoint, 50);     //Modified..... orig 10
	if ((screenPoint.x == 0) || (screenPoint.y == 0))
	{
		displayPoint.x = displayPoint.y = 0;
	}
	else
	{
		displayPoint.x = ((matrix.An * screenPoint.x) + (matrix.Bn * screenPoint.y) + matrix.Cn) / matrix.Divider;
		displayPoint.y = ((matrix.Dn * screenPoint.x) + (matrix.En * screenPoint.y) + matrix.Fn) / matrix.Divider;
    }

	if (displayPoint.x < 0)
		displayPoint.x = 0;
        
	if (displayPoint.y < 0)
		displayPoint.y = 0;

}