TSC2046.h

00001 /*
00002  *  Copyright 2013 Embedded Artists AB
00003  *
00004  *  Licensed under the Apache License, Version 2.0 (the "License");
00005  *  you may not use this file except in compliance with the License.
00006  *  You may obtain a copy of the License at
00007  *
00008  *    http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  *  Unless required by applicable law or agreed to in writing, software
00011  *  distributed under the License is distributed on an "AS IS" BASIS,
00012  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  *  See the License for the specific language governing permissions and
00014  *  limitations under the License.
00015  */
00016 
00017 #ifndef TSC2046_H
00018 #define TSC2046_H
00019 
00020 #include "TouchPanel.h"
00021 
00022 #define TSC2046_NUM_CALIB_POINTS (3)
00023 
00024 /**
00025  * Texas Instruments Touch Screen Controller (TSC2046).
00026  */
00027 class TSC2046 : public TouchPanel {
00028 public:
00029 
00030 
00031     /**
00032      * Constructor
00033      *
00034      * @param mosi SPI MOSI pin
00035      * @param miso SPI MISO pin
00036      * @param sck SPI SCK pin
00037      * @param cs chip-select pin
00038      */
00039     TSC2046(PinName mosi, PinName miso, PinName sck, PinName cs);
00040 
00041     virtual bool init(uint16_t width, uint16_t height);
00042 
00043     virtual bool read(touchCoordinate_t &coord);
00044     virtual bool calibrateStart();
00045     virtual bool getNextCalibratePoint(uint16_t* x, uint16_t* y);
00046     virtual bool waitForCalibratePoint(bool* morePoints, uint32_t timeout);
00047 
00048     /**
00049      * Calibrate the touch panel with already gathered calibration values.
00050      * The list with calibration points must at one point have been retrieved
00051      * by calling getCalibrationValues;
00052      *
00053      * @param values list with calibration values
00054      * @param numValues the size of the list must match the number of
00055      * calibration points needed for this touch panel (TSC2046_NUM_CALIB_POINTS)
00056      *
00057      * @return true if the request was successful; otherwise false
00058      */
00059     bool calibrate(touchCoordinate_t* values, int numValues);
00060 
00061     /**
00062      * Get calibration values for the calibration points used by this touch
00063      * panel. This method may only be called after a successful calibration
00064      * has been performed.
00065      *
00066      * The list with values can be written to persistent storage and used
00067      * to calibrate the display without involving the user.
00068      *
00069      * @param values calibration values will be written to this list
00070      * @param numValues the size of the list must match the number of
00071      * calibration points needed for this touch panel (TSC2046_NUM_CALIB_POINTS)
00072      *
00073      * @return true if the request was successful; otherwise false
00074      */
00075     bool getCalibrationValues(touchCoordinate_t* values, int numValues);
00076 
00077 
00078 private:
00079 
00080     typedef struct {
00081         int64_t x;
00082         int64_t y;
00083     } calibPoint_t;
00084 
00085     typedef struct {
00086         int64_t An;
00087         int64_t Bn;
00088         int64_t Cn;
00089         int64_t Dn;
00090         int64_t En;
00091         int64_t Fn;
00092         int64_t Divider;
00093     } calibMatrix_t;
00094 
00095     SPI _spi;
00096     DigitalOut _cs;
00097     bool _calibrated;
00098     bool _initialized;
00099     calibMatrix_t _calibMatrix;
00100 
00101     uint16_t _width;
00102     uint16_t _height;
00103     int _calibPoint;
00104     int _insetPx;
00105 
00106     touchCoordinate_t _calibrateValues[TSC2046_NUM_CALIB_POINTS][2];
00107 
00108     void readAndFilter(touchCoordinate_t &coord);
00109     int32_t getFilteredValue(int cmd);
00110     uint16_t spiTransfer(uint8_t cmd);
00111 
00112     void calibrate(touchCoordinate_t &ref1,
00113             touchCoordinate_t &ref2,
00114             touchCoordinate_t &ref3,
00115             touchCoordinate_t &scr1,
00116             touchCoordinate_t &scr2,
00117             touchCoordinate_t &scr3);
00118 
00119     void getCalibratePoint(int pointNum, int32_t* x, int32_t *y);
00120     int waitForTouch(int32_t* x, int32_t* y, uint32_t timeout);
00121 
00122 
00123 
00124     int setCalibrationMatrix( calibPoint_t * displayPtr,
00125             calibPoint_t * screenPtr,
00126             calibMatrix_t * matrixPtr);
00127     int getDisplayPoint( calibPoint_t * displayPtr,
00128             calibPoint_t * screenPtr,
00129             calibMatrix_t * matrixPtr );
00130 
00131 
00132 
00133 };
00134 
00135 #endif