Touch.cpp

00001 /**************************************************************************************************
00002  *****                                                                                        *****
00003  *****  Name: Touch.cpp                                                                       *****
00004  *****  Ver.: 1.0                                                                             *****
00005  *****  Date: 04/01/2013                                                                      *****
00006  *****  Auth: Frank Vannieuwkerke                                                             *****
00007  *****        Erik Olieman                                                                    *****
00008  *****  Func: Touch driver for use with ADS7843                                               *****
00009  *****                                                                                        *****
00010  *****  Code based on Carlos E. Vidales tutorial :                                            *****
00011  *****  How To Calibrate Touch Screens                                                        *****
00012  *****  www.embedded.com/design/configurable-systems/4023968/How-To-Calibrate-Touch-Screens   *****
00013  *****                                                                                        *****
00014  **************************************************************************************************/
00015 
00016 #include "Touch.h"
00017 #include "mbed.h"
00018 #include "Arial12x12.h"
00019 
00020 #define THRESHOLD 2
00021 
00022 TouchScreenADS7843::TouchScreenADS7843(PinName tp_mosi, PinName tp_miso, PinName tp_sclk, PinName tp_cs, PinName tp_irq, TFT *_LCD)
00023         : LCD(_LCD), _tp_spi(tp_mosi, tp_miso, tp_sclk), _tp_cs(tp_cs), _tp_irq(tp_irq)
00024         {
00025             DisplaySample[0].x=45;
00026             DisplaySample[0].y=45;
00027             DisplaySample[1].x=45;
00028             DisplaySample[1].y=270;
00029             DisplaySample[2].x=190;
00030             DisplaySample[2].y=190;
00031             ScreenSample[0].x=45;
00032             ScreenSample[0].y=45;
00033             ScreenSample[1].x=45;
00034             ScreenSample[1].y=270;
00035             ScreenSample[2].x=190;
00036             ScreenSample[2].y=190;
00037             _tp_cs=1;
00038             _tp_spi.frequency(500000);
00039             _tp_spi.format(8,0);                    // 8 bit spi mode 0
00040         }
00041 
00042 int TouchScreenADS7843::Read_XY(unsigned char XY)
00043 {
00044     unsigned char msb, lsb;
00045     unsigned int Temp;
00046 
00047     Temp=0;
00048     _tp_cs=0;
00049     wait_us(SPI_RD_DELAY);
00050     _tp_spi.write(XY);
00051     wait_us(SPI_RD_DELAY);
00052     msb = _tp_spi.write(0x00);  // msb
00053     wait_us(SPI_RD_DELAY);
00054     lsb = _tp_spi.write(0x00);  // lsb
00055     _tp_cs=1;
00056     Temp = ((msb << 8 ) | lsb);
00057     Temp >>= 3;
00058     Temp &= 0xfff;
00059     Temp /= 4;                  // Scaling : return value range must be between 0 and 1024
00060     return(Temp);
00061 }
00062 
00063 
00064 void TouchScreenADS7843::TP_GetAdXY(int *x,int *y)
00065 {
00066     int adx,ady;
00067     adx = Read_XY(CHX);
00068     wait_us(1);
00069     ady = Read_XY(CHY);
00070     *x = adx;
00071     *y = ady;
00072 }
00073 
00074 void TouchScreenADS7843::TP_DrawPoint(unsigned int Xpos,unsigned int Ypos, unsigned int color)
00075 {
00076 //    LCD->wr_reg(0x03, 0x1030);
00077 //    LCD->WindowMax();
00078     LCD->pixel(Xpos,Ypos,color);
00079     LCD->pixel(Xpos+1,Ypos,color);
00080     LCD->pixel(Xpos,Ypos+1,color);
00081     LCD->pixel(Xpos+1,Ypos+1,color);
00082 }
00083 
00084 void TouchScreenADS7843::DrawCross(unsigned int Xpos,unsigned int Ypos)
00085 {
00086 //    LCD->rect(Xpos-7,Ypos+7,Xpos+7,Ypos-7, Red);
00087     
00088     LCD->line(Xpos-15,Ypos,Xpos-2,Ypos,White); //left
00089     LCD->line(Xpos+2,Ypos,Xpos+15,Ypos,White);
00090     LCD->line(Xpos,Ypos-15,Xpos,Ypos-2,White);
00091     LCD->line(Xpos,Ypos+2,Xpos,Ypos+15,White);
00092 
00093     LCD->line(Xpos-15,Ypos+15,Xpos-7,Ypos+15,DarkGrey);
00094     LCD->line(Xpos-15,Ypos+7,Xpos-15,Ypos+15,DarkGrey);
00095 
00096     LCD->line(Xpos-15,Ypos-15,Xpos-7,Ypos-15,DarkGrey);
00097     LCD->line(Xpos-15,Ypos-7,Xpos-15,Ypos-15,DarkGrey);
00098 
00099     LCD->line(Xpos+7,Ypos+15,Xpos+15,Ypos+15,DarkGrey);
00100     LCD->line(Xpos+15,Ypos+7,Xpos+15,Ypos+15,DarkGrey);
00101 
00102     LCD->line(Xpos+7,Ypos-15,Xpos+15,Ypos-15,DarkGrey);
00103     LCD->line(Xpos+15,Ypos-15,Xpos+15,Ypos-7,DarkGrey);
00104 }
00105 
00106 unsigned char TouchScreenADS7843::Read_Ads7843(Coordinate * screenPtr)
00107 {
00108     int m0,m1,m2,TP_X[1],TP_Y[1],temp[3];
00109     uint8_t count=0;
00110     int buffer[2][9]={{0},{0}};
00111     if (screenPtr == NULL) screenPtr = &screen;
00112     do
00113     {
00114         TP_GetAdXY(TP_X,TP_Y);
00115         buffer[0][count]=TP_X[0];
00116         buffer[1][count]=TP_Y[0];
00117         count++;
00118     }
00119     while(!_tp_irq && (count < 9));
00120     if(count==9)
00121     {
00122         temp[0]=(buffer[0][0]+buffer[0][1]+buffer[0][2])/3;
00123         temp[1]=(buffer[0][3]+buffer[0][4]+buffer[0][5])/3;
00124         temp[2]=(buffer[0][6]+buffer[0][7]+buffer[0][8])/3;
00125         m0=temp[0]-temp[1];
00126         m1=temp[1]-temp[2];
00127         m2=temp[2]-temp[0];
00128         m0=m0>0?m0:(-m0);
00129         m1=m1>0?m1:(-m1);
00130         m2=m2>0?m2:(-m2);
00131         if( (m0>THRESHOLD)  &&  (m1>THRESHOLD)  &&  (m2>THRESHOLD) ) return 0;
00132         if(m0<m1)
00133         {
00134             if(m2<m0)
00135                 screenPtr->x=(temp[0]+temp[2])/2;
00136             else
00137                 screenPtr->x=(temp[0]+temp[1])/2;
00138         }
00139         else if(m2<m1)
00140             screenPtr->x=(temp[0]+temp[2])/2;
00141         else
00142             screenPtr->x=(temp[1]+temp[2])/2;
00143 
00144         temp[0]=(buffer[1][0]+buffer[1][1]+buffer[1][2])/3;
00145         temp[1]=(buffer[1][3]+buffer[1][4]+buffer[1][5])/3;
00146         temp[2]=(buffer[1][6]+buffer[1][7]+buffer[1][8])/3;
00147         m0=temp[0]-temp[1];
00148         m1=temp[1]-temp[2];
00149         m2=temp[2]-temp[0];
00150         m0=m0>0?m0:(-m0);
00151         m1=m1>0?m1:(-m1);
00152         m2=m2>0?m2:(-m2);
00153         if( (m0>THRESHOLD)  &&  (m1>THRESHOLD)  &&  (m2>THRESHOLD) ) return 0;
00154 
00155         if(m0<m1)
00156         {
00157             if(m2<m0)
00158                 screenPtr->y=(temp[0]+temp[2])/2;
00159             else
00160                 screenPtr->y=(temp[0]+temp[1])/2;
00161         }
00162         else if(m2<m1)
00163             screenPtr->y=(temp[0]+temp[2])/2;
00164         else
00165             screenPtr->y=(temp[1]+temp[2])/2;
00166         return 1;
00167     }
00168     return 0;
00169 }
00170 
00171 uint8_t TouchScreenADS7843::setCalibrationMatrix( Coordinate * displayPtr,
00172         Coordinate * screenPtr,
00173         Matrix * matrixPtr)
00174 {
00175     uint8_t retTHRESHOLD = 0 ;
00176     // K = (Xs0 - Xs2)*(Ys1 - Ys2) - (Xs1 - Xs2)*(Ys0 - Ys2)
00177     matrixPtr->Divider = ((screenPtr[0].x - screenPtr[2].x) * (screenPtr[1].y - screenPtr[2].y)) -
00178                          ((screenPtr[1].x - screenPtr[2].x) * (screenPtr[0].y - screenPtr[2].y)) ;
00179     if( matrixPtr->Divider == 0 )
00180     {
00181         retTHRESHOLD = 1;
00182     }
00183     else
00184     {
00185         //                 (Xd0 - Xd2)*(Ys1 - Ys2) - (Xd1 - Xd2)*(Ys0 - Ys2)
00186         //            A = ---------------------------------------------------
00187         //                                   K
00188         matrixPtr->An = ((displayPtr[0].x - displayPtr[2].x) * (screenPtr[1].y - screenPtr[2].y)) -
00189                           ((displayPtr[1].x - displayPtr[2].x) * (screenPtr[0].y - screenPtr[2].y)) ;
00190         //                 (Xs0 - Xs2)*(Xd1 - Xd2) - (Xd0 - Xd2)*(Xs1 - Xs2)
00191         //            B = ---------------------------------------------------
00192         //                                   K
00193         matrixPtr->Bn = ((screenPtr[0].x - screenPtr[2].x) * (displayPtr[1].x - displayPtr[2].x)) -
00194                         ((displayPtr[0].x - displayPtr[2].x) * (screenPtr[1].x - screenPtr[2].x)) ;
00195         //                 Ys0*(Xs2*Xd1 - Xs1*Xd2) + Ys1*(Xs0*Xd2 - Xs2*Xd0) + Ys2*(Xs1*Xd0 - Xs0*Xd1)
00196         //            C = ----------------------------------------------------------------------------
00197         //                                   K
00198         matrixPtr->Cn = (screenPtr[2].x * displayPtr[1].x - screenPtr[1].x * displayPtr[2].x) * screenPtr[0].y +
00199                         (screenPtr[0].x * displayPtr[2].x - screenPtr[2].x * displayPtr[0].x) * screenPtr[1].y +
00200                         (screenPtr[1].x * displayPtr[0].x - screenPtr[0].x * displayPtr[1].x) * screenPtr[2].y ;
00201         //                 (Yd0 - Yd2)*(Ys1 - Ys2) - (Yd1 - Yd2)*(Ys0 - Ys2)
00202         //            D = ---------------------------------------------------
00203         //                                   K
00204         matrixPtr->Dn = ((displayPtr[0].y - displayPtr[2].y) * (screenPtr[1].y - screenPtr[2].y)) -
00205                         ((displayPtr[1].y - displayPtr[2].y) * (screenPtr[0].y - screenPtr[2].y)) ;
00206         //                 (Xs0 - Xs2)*(Yd1 - Yd2) - (Yd0 - Yd2)*(Xs1 - Xs2)
00207         //            E = ---------------------------------------------------
00208         //                                   K
00209         matrixPtr->En = ((screenPtr[0].x - screenPtr[2].x) * (displayPtr[1].y - displayPtr[2].y)) -
00210                         ((displayPtr[0].y - displayPtr[2].y) * (screenPtr[1].x - screenPtr[2].x)) ;
00211         //                 Ys0*(Xs2*Yd1 - Xs1*Yd2) + Ys1*(Xs0*Yd2 - Xs2*Yd0) + Ys2*(Xs1*Yd0 - Xs0*Yd1)
00212         //            F = ----------------------------------------------------------------------------
00213         //                                   K
00214         matrixPtr->Fn = (screenPtr[2].x * displayPtr[1].y - screenPtr[1].x * displayPtr[2].y) * screenPtr[0].y +
00215                         (screenPtr[0].x * displayPtr[2].y - screenPtr[2].x * displayPtr[0].y) * screenPtr[1].y +
00216                         (screenPtr[1].x * displayPtr[0].y - screenPtr[0].x * displayPtr[1].y) * screenPtr[2].y ;
00217     }
00218     return( retTHRESHOLD ) ;
00219 }
00220 
00221 uint8_t TouchScreenADS7843::getDisplayPoint(void)
00222 {
00223     uint8_t retTHRESHOLD = 0 ;
00224 
00225     if( matrix.Divider != 0 )
00226     {
00227         // XD = AX+BY+C
00228         display.x = ( (matrix.An * screen.x) +
00229                           (matrix.Bn * screen.y) +
00230                            matrix.Cn
00231                          ) / matrix.Divider ;
00232         // YD = DX+EY+F
00233         display.y = ( (matrix.Dn * screen.x) +
00234                           (matrix.En * screen.y) +
00235                            matrix.Fn
00236                          ) / matrix.Divider ;
00237     }
00238     else
00239     {
00240         retTHRESHOLD = 1;
00241     }
00242     return(retTHRESHOLD);
00243 }
00244 
00245 void TouchScreenADS7843::TouchPanel_Calibrate(void)
00246 {
00247     uint8_t i;
00248     Coordinate screen_cal;
00249     setCalibrationMatrix( &DisplaySample[0],&ScreenSample[0],&matrix) ;
00250     LCD->set_font((unsigned char*) Arial12x12);
00251     for(i=0;i<3;i++)
00252     {
00253         LCD->cls();
00254         LCD->locate(10,10);
00255         LCD->printf("Touch crosshair to calibrate");
00256         wait_ms(500);
00257         DrawCross(DisplaySample[i].x,DisplaySample[i].y);
00258         do {} while (!Read_Ads7843(&screen_cal));
00259         ScreenSample[i].x= screen_cal.x;ScreenSample[i].y= screen_cal.y;
00260     }
00261     setCalibrationMatrix( &DisplaySample[0],&ScreenSample[0],&matrix) ;
00262     LCD->cls();
00263 }
00264 
00265 void TouchScreenADS7843::GetCalibration(Matrix * matrixPtr, Coordinate * screenPtr)
00266 {
00267     uint8_t i;
00268     Matrix * mp1;
00269     mp1 = &matrix;
00270     *matrixPtr = *mp1;
00271     for(i=0;i<3;i++)
00272     {
00273         screenPtr[i].x = ScreenSample[i].x;
00274         screenPtr[i].y = ScreenSample[i].y;
00275     }
00276 }
00277 
00278 void TouchScreenADS7843::SetCalibration(Matrix * matrixPtr, Coordinate * screenPtr)
00279 {
00280     uint8_t i;
00281     Matrix * mp1;
00282     mp1 = &matrix;
00283     *mp1 = *matrixPtr;
00284     for(i=0;i<3;i++)
00285     {
00286         ScreenSample[i].x = screenPtr[i].x;
00287         ScreenSample[i].y = screenPtr[i].y;
00288     }
00289     setCalibrationMatrix( &DisplaySample[0],&ScreenSample[0],&matrix) ;
00290 }