Diff: lcd_base.h

Revision:

22:4c169297f374

Parent:

21:e5c1e8ffada1

Child:

28:7c10c8df0802

--- a/lcd_base.h	Sat Jan 26 02:55:46 2013 +0000
+++ b/lcd_base.h	Sat Jan 26 04:36:46 2013 +0000
@@ -158,6 +158,34 @@
  */
 typedef struct Bitmap_struct bitmap_t;
 
+/** \struct BacklightPwmCtrl_enum
+ *  \brief Type of backlight control for the LCD.
+ *
+ * When the selected type is \c Constant, the pin is simply on or off - there is no gradation in the intensity of the display.
+ * In this case any free pin can be used to control the backlight.  On the other hand, when PWM is used to control brightness,
+ * take care to use only PWM-able mbed pins (p21, p22, p23, p24, p25, and p26), any other pins won't work.  It is assumed that
+ * you know what you are doing, so no check is done to prevent using a non-PWM pin as assigned control pin, when either \c Direct
+ * or \c Indirect option is used.
+ *
+ * \version 0.1
+ * \remark When choosing PWM to control the backlight, you have the option to choose the pin to either source (\c Direct) or sink
+ *         (\c Indirect) the current for LCD brightness control.  Be aware that the mbed pins can source (and probably sink when
+ *         configured as inputs) only 4 mA @+3V3 VDD.  So if you are intending to use a bigger LCD, whith more LEDs in its backlight
+ *         implementation, you probably want to interface it through a small signal transistor or a small MOSFET, in order to be able
+ *         to handle a higher current without damaging your mbed.
+ * \remark As of version 0.1 (2013-01-25) the Indirect method of PWM has not been implemented yet.
+ */
+enum BacklightPwmCtrl_enum
+{
+    Constant, /**< When the pin is a simple on/off switch. */
+    Direct, /**< Control the brightness with PWM, as the control pin is sourcing the current to drive the backlight LEDs. */
+    Indirect, /**< Control the brightness with PWM, as the control pin is sinking the current which drives the backlight LEDs. */
+};
+/** \typedef backlight_t
+ *  \brief Convenience shortcut for the backlight control type.
+ */
+typedef BacklightPwmCtrl_enum backlight_t;
+
 
 /** Base class for LCD implementations.
  *
@@ -202,7 +230,7 @@
      * \remarks This function is controller-specific and needs to be
      *          implemented separately for each available display.
      */
-    virtual void Sleep( void ) = 0;
+    virtual void Sleep( void );
     
     /** Wakes up the display from sleep mode.
      *
@@ -212,7 +240,7 @@
      * \remarks This function is controller-specific and needs to be
      *          implemented separately for each available display.
      */
-    virtual void WakeUp( void ) = 0;
+    virtual void WakeUp( void );
     
     /** Set the foreground color for painting.
      *
@@ -271,6 +299,11 @@
      */
     virtual void FillScreen( int color = -1 );
     
+    /** Sets the backlight intensity in percent as a float value in the range [0.0,1.0].
+     *  \param level The backligh intensity in percent, where 0.0 is off and 1.0 is full brightness.
+     */
+    virtual void SetBacklightLevel( float level );
+    
     /** Clears the screen.
      *
      * This is the same as calling #FillScreen() or #FillScreen( -1 ) to use the background color.
@@ -408,8 +441,11 @@
      * \param CS Pin connected to the CS input of the display.
      * \param RS Pin connected to the RS input of the display.
      * \param RESET Pin connected to the RESET input of the display.
+     * \param BL Pin connected to the circuit controlling the LCD's backlight.
+     * \param blType The type of backlight to be used.
+     * \param defaultBacklight The standard backlight intensity (if using PWM control), expressed in percent as float value from 0.0 to 1.0
      */
-    LCD( unsigned short width, unsigned short height ,PinName CS, PinName RS, PinName RESET );
+    LCD( unsigned short width, unsigned short height ,PinName CS, PinName RS, PinName RESET, PinName BL, backlight_t blType, float defaultBacklight );
     
     /** Activates the display for command/data transfer.
      *
@@ -539,6 +575,10 @@
     colordepth_t    _colorDepth;
     unsigned int    _foreground, _background;
     const font_t*   _font;
+    DigitalOut*     _lcd_pin_bl;
+    PwmOut*         _bl_pwm;
+    backlight_t     _bl_type;
+    float           _bl_pwm_default, _bl_pwm_current;
 };
 
 #ifdef __cplusplus