SeeedStudioTFTv2.cpp

00001 /* mbed library for resistive touch pads
00002  * uses 4 pins - 2 IO and 2 Analog
00003 
00004  * c 2011 Peter Drescher - DC2PD
00005  *
00006  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00007  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00008  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00009  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00010  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00011  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00012  * THE SOFTWARE.
00013  */
00014 
00015 
00016 #include "mbed.h"
00017 #include "SeeedStudioTFTv2.h"
00018 
00019 SeeedStudioTFTv2::SeeedStudioTFTv2(PinName xp, PinName xm, PinName yp, PinName ym,
00020                                    PinName mosi, PinName miso, PinName sclk,
00021                                    PinName csTft, PinName dcTft, PinName blTft,
00022                                    PinName csSd):
00023 #ifdef USE_SDCARD
00024     SDFileSystem(mosi,miso,sclk,csSd, "sdc"),
00025 #endif
00026     SPI_TFT_ILI9341(mosi,miso,sclk,csTft,NC,dcTft, "tft"),
00027     bl(blTft)
00028 {
00029 #ifndef USE_SDCARD
00030     // sd card
00031     DigitalOut cs(csSd);
00032     cs = 1;
00033 #endif
00034     // backlight
00035     bl = 1;
00036     font = NULL;
00037     // touch screen pins
00038     _xp = xp;
00039     _yp = yp;
00040     _xm = xm;
00041     _ym = ym;
00042     // default touch calibration
00043     // orientation     //      0      1      2      3
00044     x_off = 108000;  //  17252  16605 108755 108000
00045     y_off =  22000;  //  22330 105819  97167  22000
00046     pp_tx =   -291;  //    378    289   -390   -291
00047     pp_ty =    356;  //    261   -355   -239    356
00048 }
00049 
00050 void SeeedStudioTFTv2::setBacklight(bool enabled)
00051 {
00052     bl = enabled;
00053 }
00054 
00055 int SeeedStudioTFTv2::readTouch(PinName p, PinName m, PinName a, PinName i)
00056 {
00057     DigitalOut _p(p);
00058     _p = 1;
00059     DigitalOut _m(m);
00060     _m = 0;
00061     AnalogIn   _a(a);
00062     AnalogIn   _i(i); // this pin has to be high Z (DigitalIn may also work)
00063     wait_us(10);
00064     return _a.read_u16();
00065 }
00066 
00067 SeeedStudioTFTv2::TOUCH SeeedStudioTFTv2::getTouch(point& p)
00068 {
00069     int y2 = readTouch(_xp,_xm,_yp,_ym);
00070     int x2 = readTouch(_yp,_ym,_xp,_xm);
00071     int y1 = readTouch(_xp,_xm,_yp,_ym);
00072     int x1 = readTouch(_yp,_ym,_xp,_xm);
00073     int xd = x1 - x2;
00074     int yd = y1 - y2;
00075     xd = (xd > 0) ? xd : -xd;
00076     yd = (yd > 0) ? xd : -xd;
00077     p.x = x1 + x2;
00078     p.y = y1 + y2;
00079 #if 0
00080     DigitalOut _p(_xp);
00081     _p = 1;
00082     DigitalOut _m(_ym);
00083     _m = 0;
00084     AnalogIn   _ax(_xm);
00085     AnalogIn   _ay(_yp);
00086     wait_us(20);
00087     int ax = _ax.read_u16();
00088     int ay = _ay.read_u16();
00089     float z = 0;
00090     z  = (float)ay / ax / x / 2 * 0x10000;
00091 #endif
00092     const int th = 8000;
00093     const int df =  100;
00094     TOUCH touch;
00095     if (x1 < th || x2 < th ||
00096             y1 < th || y2 < th) {
00097         p.x = 0;
00098         p.y = 0;
00099         touch = NO;
00100     } else if (xd > df || yd > df) {
00101         touch = MAYBE;
00102     } else {
00103         touch = YES;
00104     }
00105     //locate(0,50);
00106     //printf("x: %6i y: %6i",p.x,p.y);
00107     return touch;
00108 }
00109 
00110 void SeeedStudioTFTv2::calibrate(void)
00111 {
00112     int i;
00113     int a = 0,b = 0,c = 0, d = 0;
00114     int pos_x = 0, pos_y = 0;
00115     point p;
00116 
00117     cls();
00118     foreground(White);    // set chars to white
00119     line(0,3,6,3,White);
00120     line(3,0,3,6,White);
00121     if (font)
00122     {
00123         // get the center of the screen
00124         pos_x = columns() / 2 - 3;
00125         pos_x = pos_x * font[1];
00126         pos_y = (rows() / 2) - 1;
00127         pos_y = pos_y * font[2];
00128         locate(pos_x,pos_y);
00129         printf("press cross    ");
00130         locate(pos_x,pos_y + font[2]);
00131         printf("to calibrate   ");
00132     }
00133     for (i=0; i<5; i++) {
00134         while (getTouch(p) != YES)
00135             /*nothing*/;
00136         a += p.x;
00137         b += p.y;
00138     }
00139     a = a / 5;
00140     b = b / 5;
00141     if (font)
00142     {
00143         locate(pos_x,pos_y);
00144         printf("ok             ");
00145         locate(pos_x,pos_y + font[2]);
00146         printf("release touch  ");
00147     }
00148     while (getTouch(p) != NO)
00149         /*nothing*/;
00150     cls();
00151     line(width() -5, height() - 8,width() - 5,height() -1,White);   // paint cross
00152     line(width() - 8,height() - 5,width() - 1,height() - 5,White);
00153     if (font)
00154     {
00155         locate(pos_x,pos_y);
00156         printf("press cross    ");
00157         locate(pos_x,pos_y + font[2]);
00158         printf("to calibrate   ");
00159     }
00160     for (i=0; i<5; i++) {
00161         while (getTouch(p) != YES)
00162             /*nothing*/;
00163         c+= p.x;
00164         d+= p.y;
00165     }
00166     c = c / 5;
00167     d = d / 5;
00168     x_off = a;
00169     y_off = b;
00170     i = c-a;  // delta x
00171     pp_tx = i / (width() - 6);
00172     i = d-b;  // delta y
00173     pp_ty = i / (height() - 6);
00174     if (font)
00175     {
00176         locate(pos_x,pos_y);
00177         printf("Calibrated     ");
00178         locate(pos_x,pos_y + font[2]);
00179         printf("x %6i %4i", x_off, pp_tx);
00180         locate(pos_x,pos_y + 2*font[2]);
00181         printf("y %6i %4i", y_off, pp_ty);
00182     }
00183     while (getTouch(p) != NO)
00184         /*nothing*/;
00185     cls();
00186 }
00187 
00188 point SeeedStudioTFTv2::toPixel(point p)
00189 {
00190     p.x -= x_off;
00191     p.x /= pp_tx;
00192     int w = width();
00193     if (p.x > w) p.x = w;
00194     if (p.x < 0) p.x = 0;
00195     p.y -= y_off;
00196     p.y /= pp_ty;
00197     int h = height();
00198     if (p.y > h) p.y = h;
00199     if (p.y < 0) p.y = 0;
00200     return (p);
00201 }
00202 
00203 bool SeeedStudioTFTv2::getPixel(point& p)
00204 {
00205     TOUCH touch = getTouch(p);
00206     p = toPixel(p);
00207     return touch == YES;
00208 }