Revision 22:4c169297f374, committed 2013-01-26

Comitter:

ttodorov

Date:

Sat Jan 26 04:36:46 2013 +0000

Parent:

21:e5c1e8ffada1

Child:

23:eca4414196ca

Commit message:

- added PWM backlight control

Changed in this revision

--- a/hx8340bs.cpp	Sat Jan 26 02:55:46 2013 +0000
+++ b/hx8340bs.cpp	Sat Jan 26 04:36:46 2013 +0000
@@ -22,11 +22,9 @@
 #include "hx8340bs.h"
 #include "helpers.h"
 
-HX8340S_LCD::HX8340S_LCD( PinName CS, PinName RESET, PinName SCL, PinName SDI, PinName BL )
-    : LCD( 176, 220, CS, NC, RESET ), _lcd_pin_scl( SCL ), _lcd_pin_sdi( SDI )
+HX8340S_LCD::HX8340S_LCD( PinName CS, PinName RESET, PinName SCL, PinName SDI, PinName BL, backlight_t blType, float defaultBackLightLevel )
+    : LCD( 176, 220, CS, NC, RESET, BL, blType, defaultBackLightLevel ), _lcd_pin_scl( SCL ), _lcd_pin_sdi( SDI )
 {
-    if ( BL != NC ) _lcd_pin_bl = new DigitalOut( BL );
-    else _lcd_pin_bl = 0;
 }
 
 void HX8340S_LCD::Initialize( orientation_t orientation, colordepth_t colors )
@@ -45,6 +43,8 @@
     _lcd_pin_sdi = HIGH;
     if ( _lcd_pin_bl != 0 )
         *_lcd_pin_bl = HIGH;
+    else if ( _bl_pwm != 0 )
+        *_bl_pwm = _bl_pwm_default;
     wait_ms( 55 );
     
     Activate();
@@ -136,8 +136,7 @@
     wait_ms( 10 );
     WriteCmd( 0x10 );
     wait_ms( 125 );
-    if ( _lcd_pin_bl != 0 )
-        *_lcd_pin_bl = LOW;
+    LCD::Sleep();
     Deactivate();
 }
 
@@ -148,8 +147,7 @@
     wait_ms( 10 );
     WriteCmd( 0x11 );
     wait_ms( 125 );
-    if ( _lcd_pin_bl != 0 )
-        *_lcd_pin_bl = HIGH;
+    LCD::WakeUp();
     Deactivate();
 }
 

--- a/hx8340bs.h	Sat Jan 26 02:55:46 2013 +0000
+++ b/hx8340bs.h	Sat Jan 26 04:36:46 2013 +0000
@@ -84,8 +84,10 @@
      * \param SCL Pin for the serial clock signal.
      * \param SDI Pin for the serial data signal.
      * \param BL Pin for controlling the backlight. By default not used.
+     * \param blType The backlight type, the default is to utilize the pin - if supplied - as a simple on/off switch
+     * \param defaultBacklightLevel If using PWM to control backlight, this would be the default brightness in percent after LCD initialization.
      */
-    HX8340S_LCD( PinName CS, PinName RESET, PinName SCL, PinName SDI, PinName BL = NC );
+    HX8340S_LCD( PinName CS, PinName RESET, PinName SCL, PinName SDI, PinName BL = NC, backlight_t blType = Constant, float defaultBackLightLevel = 1.0 );
     
     /** Initialize display.
      *
@@ -182,7 +184,6 @@
     
 private:
     DigitalOut  _lcd_pin_scl, _lcd_pin_sdi;
-    DigitalOut* _lcd_pin_bl;
 };
 
 #ifdef __cplusplus

--- a/lcd_base.cpp	Sat Jan 26 02:55:46 2013 +0000
+++ b/lcd_base.cpp	Sat Jan 26 04:36:46 2013 +0000
@@ -22,12 +22,54 @@
 #include "lcd_base.h"
 #include "helpers.h"
 
-LCD::LCD( unsigned short width, unsigned short height ,PinName CS, PinName RS, PinName RESET )
-    : _disp_width( width ), _disp_height( height ), _lcd_pin_cs( CS ), _lcd_pin_rs( RS ), _lcd_pin_reset( RESET )
+LCD::LCD( unsigned short width, unsigned short height ,PinName CS, PinName RS, PinName RESET, PinName BL, backlight_t blType, float defaultBacklight )
+    : _disp_width( width ), _disp_height( height ), _lcd_pin_cs( CS ), _lcd_pin_rs( RS ), _lcd_pin_reset( RESET ), _bl_type( blType )
 {
     SetForeground();
     SetBackground();
     _font = &TerminusFont;
+    if ( defaultBacklight < 0 ) _bl_pwm_default = 0;
+    else if ( defaultBacklight > 1.0 ) _bl_pwm_default = 1.0;
+    else _bl_pwm_default = defaultBacklight;
+    if ( BL != NC )
+    {
+        if ( blType == Constant )
+        {
+            _bl_pwm = 0;
+            _lcd_pin_bl = new DigitalOut( BL );
+        }
+        else
+        {
+            _lcd_pin_bl = 0;
+            _bl_pwm = new PwmOut( BL );
+            _bl_pwm->period_ms( 8.33 ); // 120 Hz
+            _bl_pwm_current = _bl_pwm_default;
+            // initially off
+            *_bl_pwm = 0;
+        }
+        
+    }
+    else
+    {
+        _lcd_pin_bl = 0;
+        _bl_pwm = 0;
+    }
+}
+
+void LCD::Sleep( void )
+{
+    if ( _lcd_pin_bl != 0 )
+        *_lcd_pin_bl = LOW;
+    else if ( _bl_pwm != 0 )
+        *_bl_pwm = 0;
+}
+
+void LCD::WakeUp( void )
+{
+    if ( _lcd_pin_bl != 0 )
+        *_lcd_pin_bl = HIGH;
+    else if ( _bl_pwm != 0 )
+        *_bl_pwm = _bl_pwm_current;
 }
 
 inline
@@ -75,6 +117,26 @@
     return 0;
 }
 
+void LCD::SetBacklightLevel( float level )
+{
+    switch ( _bl_type )
+    {
+        case Direct:
+            if ( _bl_pwm != 0 )
+            {
+                *_bl_pwm = level;
+                _bl_pwm_current = level;
+            }
+            break;
+            
+        case Indirect:
+            break;
+        case Constant:
+        default:
+            break;
+    }
+}
+
 void LCD::FillScreen( int color )
 {
     unsigned int rgb = color == -1 ? _background : color == -2 ? _foreground : ( unsigned int ) color;

--- 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

--- a/ssd1289.cpp	Sat Jan 26 02:55:46 2013 +0000
+++ b/ssd1289.cpp	Sat Jan 26 04:36:46 2013 +0000
@@ -22,12 +22,10 @@
 #include "ssd1289.h"
 #include "helpers.h"
 
-SSD1289_LCD::SSD1289_LCD( PinName CS, PinName RESET, PinName RS, PinName WR, BusOut* DATA_PORT, PinName BL, PinName RD )
-    : LCD( 240, 320, CS, RS, RESET ), _lcd_pin_wr( WR )
+SSD1289_LCD::SSD1289_LCD( PinName CS, PinName RESET, PinName RS, PinName WR, BusOut* DATA_PORT, PinName BL, PinName RD, backlight_t blType, float defaultBackLightLevel )
+    : LCD( 240, 320, CS, RS, RESET, BL, blType, defaultBackLightLevel ), _lcd_pin_wr( WR )
 {
     _lcd_port = DATA_PORT;
-    if ( BL != NC ) _lcd_pin_bl = new DigitalOut( BL );
-    else _lcd_pin_bl = 0;
     if ( RD != NC ) _lcd_pin_rd = new DigitalOut( RD );
     else _lcd_pin_rd = 0;
 }
@@ -45,6 +43,8 @@
     _lcd_pin_cs = HIGH;
     if ( _lcd_pin_bl != 0 )
         *_lcd_pin_bl = HIGH;
+    else if ( _bl_pwm != 0 )
+        *_bl_pwm = _bl_pwm_default;
     if ( _lcd_pin_rd != 0 )
         *_lcd_pin_rd = HIGH;
     _lcd_pin_wr = HIGH;
@@ -197,15 +197,13 @@
 void SSD1289_LCD::Sleep( void )
 {
     WriteCmdData( 0x10, 0x0001 ); // sleep mode: 0 = exit, 1 = enter
-    if ( _lcd_pin_bl != 0 )
-        *_lcd_pin_bl = LOW;
+    LCD::Sleep();
 }
 
 void SSD1289_LCD::WakeUp( void )
 {
     WriteCmdData( 0x10, 0x0000 ); // sleep mode: 0 = exit, 1 = enter
-    if ( _lcd_pin_bl != 0 )
-        *_lcd_pin_bl = HIGH;
+    LCD::WakeUp();
 }
 
 void SSD1289_LCD::WriteCmd( unsigned short cmd )

--- a/ssd1289.h	Sat Jan 26 02:55:46 2013 +0000
+++ b/ssd1289.h	Sat Jan 26 04:36:46 2013 +0000
@@ -91,8 +91,10 @@
      * \param RD Pin for the RD signal. This line is not needed by the driver, so if you would like to
      *       use the pin on the mbed for something else, just pull-up the respective pin on the LCD high,
      *       and do not assign a value to this parameter when creating the controller instance.
+     * \param blType The backlight type, the default is to utilize the pin - if supplied - as a simple on/off switch
+     * \param defaultBacklightLevel If using PWM to control backlight, this would be the default brightness in percent after LCD initialization.
      */
-    SSD1289_LCD( PinName CS, PinName RESET, PinName RS, PinName WR, BusOut* DATA_PORT, PinName BL = NC, PinName RD = NC );
+    SSD1289_LCD( PinName CS, PinName RESET, PinName RS, PinName WR, BusOut* DATA_PORT, PinName BL = NC, PinName RD = NC, backlight_t blType = Constant, float defaultBackLightLevel = 1.0 );
     
     /** Initialize display.
      *

--- a/st7735.cpp	Sat Jan 26 02:55:46 2013 +0000
+++ b/st7735.cpp	Sat Jan 26 04:36:46 2013 +0000
@@ -22,11 +22,9 @@
 #include "st7735.h"
 #include "helpers.h"
 
-ST7735_LCD::ST7735_LCD( PinName CS, PinName RESET, PinName RS, PinName SCL, PinName SDA, PinName BL )
-    : LCD( 128, 160, CS, RS, RESET ), _lcd_pin_scl( SCL ), _lcd_pin_sda( SDA )
+ST7735_LCD::ST7735_LCD( PinName CS, PinName RESET, PinName RS, PinName SCL, PinName SDA, PinName BL, backlight_t blType, float defaultBackLightLevel )
+    : LCD( 128, 160, CS, RS, RESET, BL, blType, defaultBackLightLevel ), _lcd_pin_scl( SCL ), _lcd_pin_sda( SDA )
 {
-    if ( BL != NC ) _lcd_pin_bl = new DigitalOut( BL );
-    else _lcd_pin_bl = 0;
 }
 
 void ST7735_LCD::Initialize( orientation_t orientation, colordepth_t colors )
@@ -46,6 +44,8 @@
     _lcd_pin_sda = HIGH;
     if ( _lcd_pin_bl != 0 )
         *_lcd_pin_bl = HIGH;
+    else if ( _bl_pwm != 0 )
+        *_bl_pwm = _bl_pwm_default;
     wait_ms( 55 );
     
     Activate();
@@ -181,8 +181,7 @@
     wait_ms( 10 );
     WriteCmd( 0x10 );
     wait_ms( 125 );
-    if ( _lcd_pin_bl != 0 )
-        *_lcd_pin_bl = LOW;
+    LCD::Sleep();
     Deactivate();
 }
 
@@ -193,8 +192,7 @@
     wait_ms( 10 );
     WriteCmd( 0x11 );
     wait_ms( 125 );
-    if ( _lcd_pin_bl != 0 )
-        *_lcd_pin_bl = HIGH;
+    LCD::WakeUp();
     Deactivate();
 }
 

--- a/st7735.h	Sat Jan 26 02:55:46 2013 +0000
+++ b/st7735.h	Sat Jan 26 04:36:46 2013 +0000
@@ -85,8 +85,10 @@
      * \param SCL Pin for the serial clock line.
      * \param SDA Pin for the serial data line.
      * \param BL Pin for controlling the backlight. By default not used.
+     * \param blType The backlight type, the default is to utilize the pin - if supplied - as a simple on/off switch
+     * \param defaultBacklightLevel If using PWM to control backlight, this would be the default brightness in percent after LCD initialization.
      */
-    ST7735_LCD( PinName CS, PinName RESET, PinName RS, PinName SCL, PinName SDA, PinName BL = NC );
+    ST7735_LCD( PinName CS, PinName RESET, PinName RS, PinName SCL, PinName SDA, PinName BL = NC, backlight_t blType = Constant, float defaultBackLightLevel = 1.0 );
     
     /** Initialize display.
      *