GUITDRV_ADS7846.h

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00011 
00012 ** emWin V5.38 - Graphical user interface for embedded applications **
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00014 emWin is protected by  international copyright laws.  Knowledge of the
00015 source code may not be used to write a similar product.  This file may
00016 only be used in accordance with the following terms:
00017 
00018 The software has been licensed to  NXP Semiconductors USA, Inc.  whose
00019 registered  office  is  situated  at 411 E. Plumeria Drive, San  Jose,
00020 CA 95134, USA  solely for  the  purposes  of  creating  libraries  for
00021 NXPs M0, M3/M4 and  ARM7/9 processor-based  devices,  sublicensed  and
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00023 Agreement.
00024 Full source code is available at: www.segger.com
00025 
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00027 ----------------------------------------------------------------------
00028 Licensing information
00029 
00030 Licensor:                 SEGGER Microcontroller Systems LLC
00031 Licensed to:              NXP Semiconductors, 1109 McKay Dr, M/S 76, San Jose, CA 95131, USA
00032 Licensed SEGGER software: emWin
00033 License number:           GUI-00186
00034 License model:            emWin License Agreement, dated August 20th 2011
00035 Licensed product:         -
00036 Licensed platform:        NXP's ARM 7/9, Cortex-M0,M3,M4
00037 Licensed number of seats: -
00038 ----------------------------------------------------------------------
00039 File        : GUITDRV_ADS7846.h
00040 Purpose     : Touch screen driver include
00041 ----------------------------------------------------------------------
00042 
00043 Notes
00044 =====
00045 (1) The driver needs some function pointer to be filled correctly to be able
00046     to communicate with the external peripheral correctly. The correct assignment
00047     of these function pointers is checked during driver configuration.
00048     
00049 (2) The driver needs some configuration variables filled in to be able to calculate
00050     the logical screen coordinates from the physical AD values.
00051     A description of the typical paramaters that have to be known by the driver is
00052     listed below:
00053     - Orientation: Orientation of the touch screen if not the same as the physical orientation.
00054                    A or-combination of the defines GUI_SWAP_XY, GUI_MIRROR_X and GUI_MIRROR_Y
00055                    can be used.
00056     - xLog0      : Logical pixel value of horizontal reference point 0. Typically 0.
00057     - xLog1      : Logical pixel value of horizontal reference point 1. Typically horizontal screen resolution -1.
00058     - xPhys0     : Physical AD value of horizontal reference point 0.
00059     - xPhys1     : Physical AD value of horizontal reference point 1.
00060     - yLog0      : Logical pixel value of vertical reference point 0. Typically 0.
00061     - yLog1      : Logical pixel value of vertical reference point 1. Typically vertical screen resolution -1.
00062     - yPhys0     : Physical AD value of vertical reference point 0.
00063     - yPhys1     : Physical AD value of vertical reference point 1.
00064 
00065 (3) If the PENIRQ line of the touch controller is connected to a port of the target hardware
00066     a touch event can be detected by the driver. Upon polling the driver's exec routine the
00067     driver can check if a touch event is ready to be sampled by checking the PENIRQ line.
00068     Without PENIRQ line the driver will always try to sample a touch event even if no touch
00069     happened which will consume time even if not necessary.
00070     Without PENIRQ it is the responsibility of the user's pfGetResult() routine to return
00071     0xFFFF if the measured AD value is out of bounds.
00072     If both, the PENIRQ and the touch pressure recognition are enabled first the PENIRQ will
00073     signal that there is a touch event. Afterwards the touch pressure measurement is used to
00074     confirm that this was a valid touch and the touch had enough pressure to deliver good
00075     measurements.
00076 
00077 (4) The touch pressure measurement is activated by setting a value for PressureMin and
00078     PressureMax .
00079     To calculate the correct touch pressure the resistance of the X-plate has to be known.
00080     This can be set via PlateResistanceX [Ohm].
00081     A touch event that we have measured with a pressure within these thresholds is confirmed
00082     as valid touch event with good measurment samples.
00083     If both, the PENIRQ and the touch pressure recognition are enabled first the PENIRQ will
00084     signal that there is a touch event. Afterwards the touch pressure measurement is used to
00085     confirm that this was a valid touch and the touch had enough pressure to deliver good
00086     measurements.
00087     If no PENIRQ line is connected this measurement takes place everytime the touch event is
00088     polled regardless if there is a touch event or not as the driver will only know for sure
00089     after calculating the touch pressure.
00090     Setting the value for PlateResistanceX to 0 is invalid. The driver will internally use a
00091     value of 1 instead.
00092 */
00093 
00094 #ifndef GUITDRV_ADS7846_H            /* Make sure we only include it once */
00095 #define GUITDRV_ADS7846_H
00096 
00097 #include "GUI_Type.h"
00098 
00099 #if defined(__cplusplus)
00100 extern "C" {     /* Make sure we have C-declarations in C++ programs */
00101 #endif
00102 
00103 /*********************************************************************
00104 *
00105 *       Types
00106 *
00107 **********************************************************************
00108 */
00109 
00110 typedef struct {
00111   //
00112   // Function pointer (1)
00113   //
00114   void     (* pfSendCmd)   (U8 Data);     // Sends a 8-bit command to the peripheral
00115   U16      (* pfGetResult) (void);        // Retrieves the result of the AD conversion. 4 dummy bytes have to be shifted out to the left.
00116   char     (* pfGetBusy)   (void);        // Retrieves the status of the busy line. 0: Not busy; 1: Busy
00117   void     (* pfSetCS)     (char OnOff);  // Set chip select line. OnOff == 1 means peripheral selected
00118   //
00119   // Configuration (2)
00120   //
00121   unsigned Orientation;
00122   int      xLog0;
00123   int      xLog1;
00124   int      xPhys0;
00125   int      xPhys1;
00126   int      yLog0;
00127   int      yLog1;
00128   int      yPhys0;
00129   int      yPhys1;
00130   //
00131   // Optional, touch recognition via PENIRQ line (3)
00132   //
00133   char     (* pfGetPENIRQ) (void);        // Retrieves the status of the PENIRQ line to detect a touch event.
00134   //
00135   // Optional, touch recognition via touch pressure measurement (4)
00136   //
00137   int      PressureMin;                   // Minimum pressure threshold. A measured pressure below this value means we do not have a valid touch event.
00138   int      PressureMax;                   // Maximum pressure threshold. A measured pressure above this value means we do not have a valid touch event.
00139   int      PlateResistanceX;              // Resistance of the X-plate of the touch screen. This value is needed for calculation of the touch pressure.
00140 } GUITDRV_ADS7846_CONFIG;
00141 
00142 typedef struct {
00143   int      xPhys;     // Last measured x value
00144   int      yPhys;     // Last measured y value
00145   int      z1Phys;    // Last measured z1 value
00146   int      z2Phys;    // Last measured z2 value
00147   int      PENIRQ;    // Last sampled PENIRQ state if PENIRQ callback has been set
00148   int      Pressure;  // Last measured touch pressure if touch pressure measurement is enabled
00149 } GUITDRV_ADS7846_LAST_VAL;
00150 
00151 /*********************************************************************
00152 *
00153 *       Prototypes
00154 *
00155 **********************************************************************
00156 */
00157 
00158 void GUITDRV_ADS7846_Config    (GUITDRV_ADS7846_CONFIG * pConfig);
00159 char GUITDRV_ADS7846_Exec      (void);
00160 void GUITDRV_ADS7846_GetLastVal(GUITDRV_ADS7846_LAST_VAL * p);
00161 
00162 #if defined(__cplusplus)
00163 }                /* Make sure we have C-declarations in C++ programs */
00164 #endif
00165 
00166 
00167 #endif   /* GUITDRV_ADS7846_H */
00168 
00169 /*************************** End of file ****************************/