File content as of revision 22:62f3bed03503:

/******************************************************************
 *****                                                        *****
 *****  Name: Touch.h                                         *****
 *****  Ver.: 1.0                                             *****
 *****  Date: 04/01/2013                                      *****
 *****  Auth: Frank Vannieuwkerke                             *****
 *****        Erik Olieman                                    *****
 *****  Func: Touch driver for use with ADS7843               *****
 *****                                                        *****
 ******************************************************************/

#ifndef MBED_Touch_H
#define MBED_Touch_H

#include "TFT.h"
#include "mbed.h"

    typedef struct
    {
       int x;
       int y;
    } Coordinate;

    typedef struct
    {
    int         An,
                Bn,
                Cn,
                Dn,
                En,
                Fn,
                Divider ;
    } Matrix;

class TouchScreenADS7843 {
public:
    Coordinate  display;
    Coordinate  screen;

    /*
    * Create a Touchscreen object connected to SPI and two pins.
    *
    * @param mosi,miso,sclk SPI
    * @param cs pin connected to CS of ADS7843
    * @param irq pin connected to IRQ of ADS7843
    * @param pointer to SPI_TFT constructor
    *
    */
    TouchScreenADS7843(PinName tp_mosi, PinName tp_miso, PinName tp_sclk, PinName tp_cs, PinName tp_irq, TFT *_LCD);

    /*
    * Draw a 2 by 2 dot on the LCD screen.
    *
    * @param x (horizontal position)
    * @param y (vertical position)
    * @param color (16 bit pixel color)
    *
    */
    void TP_DrawPoint(unsigned int Xpos,unsigned int Ypos,unsigned int color);
    
    /*
    * Obtain averaged data from ADS7846.
    * does 9 consecutive reads and only stores averaged data
    * when the 9 points are within the treshold limits.
    *
    * @param screenPTR (pointer to store data)
    * @returns 1 on success
    * @returns 0 on failure
    *
    * If called with screenPTR = NULL - 'screen' variable is used, otherwise (parameter) is used.
    *
    */
    unsigned char Read_Ads7843(Coordinate * screenPtr = NULL);

    /*
    * Calibrate the touch panel.
    * Three crosshairs are drawn and need to be touched in sequence.  
    * A calibration matrix is set accordingly.
    *
    */
    void TouchPanel_Calibrate(void);
    
    /*
    * Obtain real x,y coordinates.
    * The x,y coordinates are calculated using the calibration matrix.
    *
    */
    unsigned char getDisplayPoint(void);

    /*
    * Read touchpanel screensample and matrix values.
    * 
    * In your code, create 2 structures using Matrix and screenPtr
    * and call this function with these structures.
    * the calibration values are returned into these structures.
    * Example:
    * Matrix matrix;
    * Coordinate ScreenSample[3];
    * GetCalibration(&matrix, &ScreenSample[0]);
    */
    void GetCalibration(Matrix * matrixPtr, Coordinate * screenPtr);

    /*
    * Set touchpanel calibration using screensample and matrix values.
    * 
    * In your code, create 2 structures based on Matrix and screenPtr,
    * copy saved calibration values into these structures
    * and call this function with these structures.
    * Example:
    * Matrix matrix;
    * Coordinate ScreenSample[3];
    * <pseudocode> load matrix with values from external storage (eg eeprom).
    * <pseudocode> load ScreenSample with values from external storage (eg eeprom).
    * SetCalibration(&matrix, &ScreenSample[0]);
    */
    void SetCalibration(Matrix * matrixPtr, Coordinate * screenPtr);

    TFT    *LCD;
    SPI        _tp_spi;
    DigitalOut _tp_cs;
    DigitalIn  _tp_irq;

protected:

    #define    SPI_RD_DELAY    1
    #define    CHX             0xd0    // 12 bit mode
    #define    CHY             0x90

    Coordinate DisplaySample[3];
    Coordinate ScreenSample[3];
    Matrix matrix;

    /*
    * Obtain raw x,y data from ADS7846
    *
    * @param pointer to raw x and y coordinates (pointer to store data)
    * @returns x (horizontal position)
    * @returns y (vertical position)
    *
    */
    void TP_GetAdXY(int *x,int *y);
    
    /*
    * Obtain raw single channel data from ADS7846 (Called by TP_GetADXY)
    *
    * @param channel to be read (CHX or CHY)
    * @returns raw scaled down value (return value range must be between 0 and 1024)
    *
    */
    int Read_XY(unsigned char XY);
    
    /*
    * Draw a calibration crosshair on the LCD screen
    *
    * @param x (horizontal position)
    * @param y (vertical position)
    *
    */
    void DrawCross(unsigned int Xpos,unsigned int Ypos);
    
    /*
    * Set the calibration matrix
    *
    * @param displayPTR (pointer to display data)
    * @param screenPTR  (pointer to screen data)
    * @param matrixPTR  (pointer to calibration matrix)
    *
    * @returns 0 when matrix.divider != 0
    * @returns 1 when matrix.divider = 0
    *
    */
    unsigned char setCalibrationMatrix( Coordinate * displayPtr,Coordinate * screenPtr,Matrix * matrixPtr);

};
#endif