Diff: TouchScreen.h

Revision:

0:3f0160100cc9

Child:

1:9bd85d0331a8

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TouchScreen.h	Sat Mar 19 15:39:36 2016 +0000
@@ -0,0 +1,176 @@
+#ifndef TOUCHSCREEN_H
+#define TOUCHSCREEN_H
+
+/**
+* An interrupt-driven library to interface with touch-screens using the ADS7843 chip.
+*
+*
+**/
+#include "mbed.h"
+#include "rtos.h"
+
+#define TOUCHSCREEN_SPI_FREQUENCY 500000
+
+#define TOUCHSCREEN_CMD_GETX 0x90
+#define TOUCHSCREEN_CMD_GETY 0xD0
+#define TOUCHSCREEN_PRECISION_8 0x08
+#define TOUCHSCREEN_PRECISION_12 0x00
+
+#define TOUCHSCREEN_SIGNAL_START 0x01
+#define TOUCHSCREEN_SIGNAL_END 0x02
+#define TOUCHSCREEN_SIGNAL_POLL 0x04
+
+#define TOUCHSCREEN_POLL_MICROS 50000
+
+/**
+* Default value for how far the touch position must have moved before a new TouchMove event is raised
+**/
+#define TOUCHSCREEN_MOVEMENT_THRESHOLD 4
+#define TOUCHSCREEN_DEBOUNCE_MICROS 50000
+
+#define TOUCHSCREEN_STATE_IDLE 0
+#define TOUCHSCREEN_STATE_DEBOUNCE 1
+#define TOUCHSCREEN_STATE_POLL 2
+
+#define TOUCHSCREEN_ORIENTATION_LANDSCAPE 0
+#define TOUCHSCREEN_ORIENTATION_PORTRAIT 1
+#define TOUCHSCREEN_ORIENTATION_ROTATED 2
+
+typedef struct TouchPosition {
+    // Raw touch position 0 - 4095
+    int x;
+    int y;
+    
+    // Touch position in screen pixels
+    int screenX;
+    int screenY;
+    
+    bool valid;
+} TouchPosition;
+
+typedef void (* TouchCallbackHandler)(TouchPosition p);
+
+class TouchScreen
+{
+
+public:
+
+    /**
+    * Basic setup uses hard-coded defaults so the screen can do something.
+    * you'll want to setLCDGeometry() and setCalibration() for your screen
+    * Use the TouchScreenCalibrate program to get calibration data for your screen
+    **/
+    TouchScreen(PinName mosi, PinName miso, PinName sclk, PinName cs, PinName irq);
+    
+    /**
+    * Register a handler which will be called every time a touch is detected on the screen
+    **/
+    void setTouchStartHandler(TouchCallbackHandler handler);
+    
+    /**
+    * Register a handler which will be called every time a movement greater than a given threshold is detected.
+    * You can set the threshold with the setMovementThreshold() method
+    **/
+    void setTouchMoveHandler(TouchCallbackHandler handler);
+    
+    /**
+    * Register a handler which will be called when a touch stops being detected
+    **/
+    void setTouchEndHandler(TouchCallbackHandler handler);
+    
+    /**
+    * Set the dimensions and orientation of the LCD screen
+    **/
+    void setLCDGeometry(int width, int height, uint8_t orientation);
+    
+    /**
+    * Set the calibration data used to calculate the screen position in pixels of a touch
+    **/
+    void setCalibration(int xmin, int xmax, int ymin, int ymax);
+    
+    /**
+    * Set the amount of movement which must occur before a TouchMove event is raised
+    **/
+    void setMovementTheshold(int thresholdInPixels);
+    
+private:
+
+    /**
+    * SPI control
+    **/
+    SPI  _spi ;
+    DigitalOut _cs ;
+    
+    /**
+    * The interrupt pin and its handler
+    **/
+    DigitalIn _intPin;
+    InterruptIn _int;
+    
+    uint8_t _precision;
+    
+    int _lcdWidth;
+    int _lcdHeight;
+    uint8_t _lcdOrientation;
+    
+    int _xmin, _xmax, _ymin, _ymax;
+    int _movementThresholdSquared;
+    
+    TouchPosition _currentPosition;
+    TouchPosition _lastPosition;
+
+    unsigned int _read(uint8_t cmd);
+    
+    volatile uint8_t _state;
+    
+    void _fallInterruptHandler();
+    void _riseInterruptHandler();
+    void _tickerInterruptHandler();
+    
+    
+    void _handleTouchStart();
+    void _handleTouchMoved();
+    void _handleTouchEnd();
+    
+    bool _moved(TouchPosition a, TouchPosition b);
+    
+    TouchPosition _getPosition();
+
+    TouchCallbackHandler _touchStartHandler;
+    TouchCallbackHandler _touchMoveHandler;
+    TouchCallbackHandler _touchEndHandler;
+    
+    Thread* _handlerThread;
+    
+    // Used to poll the screen while it is being touched to track movement and to debounce edge changes
+    Ticker _ticker;
+   
+    /**
+    * Needs to be static because a Thread can't be started on an instance method.
+    **/
+    static void _monitor(void const *touchScreen) {
+        
+        TouchScreen* screen = (TouchScreen*)touchScreen;
+
+        while(true) {
+            osEvent evt = Thread::signal_wait(0);
+            if(evt.status == osEventSignal) {
+                if(evt.value.signals & TOUCHSCREEN_SIGNAL_START) {
+                    screen->_handlerThread->signal_clr(TOUCHSCREEN_SIGNAL_START);
+                    screen->_handleTouchStart();
+                }
+                if(evt.value.signals & TOUCHSCREEN_SIGNAL_END) {
+                    screen->_handlerThread->signal_clr(TOUCHSCREEN_SIGNAL_END);
+                    screen->_handleTouchEnd();
+                }
+                if(evt.value.signals & TOUCHSCREEN_SIGNAL_POLL) {
+                    screen->_handlerThread->signal_clr(TOUCHSCREEN_SIGNAL_POLL);
+                    screen->_handleTouchMoved();
+                }
+            }
+        }
+    }
+
+};
+
+#endif
\ No newline at end of file