Merge pull request #819 from neildarlow/Marlin_v1

Activate LiquidTWI2 device detection and space-pad LCD status line.

Marlin/Marlin_main.cpp

         }
         lcd_ignore_click(false);
       }else{
+          if (!lcd_detected())
+            break;
         while(!lcd_clicked()){
           manage_heater();
           manage_inactivity();

Marlin/cardreader.cpp

   if(root.isOpen())
     root.close();
 #ifdef SDSLOW
-  if (!card.init(SPI_HALF_SPEED,SDSS))
+  if (!card.init(SPI_HALF_SPEED,SDSS)
+  #if defined(LCD_SDSS) && (LCD_SDSS != SDSS)
+    && !card.init(SPI_HALF_SPEED,LCD_SDSS)
+  #endif
+    )
 #else
-  if (!card.init(SPI_FULL_SPEED,SDSS))
+  if (!card.init(SPI_FULL_SPEED,SDSS)
+  #if defined(LCD_SDSS) && (LCD_SDSS != SDSS)
+    && !card.init(SPI_FULL_SPEED,LCD_SDSS)
+  #endif
+    )
 #endif
   {
     //if (!card.init(SPI_HALF_SPEED,SDSS))

Marlin/pins.h

         #define BTN_EN1 47  //reverse if the encoder turns the wrong way.
         #define BTN_EN2 43
         #define BTN_ENC 32
-        #define SDSS 53
+        #define LCD_SDSS 53
         #define SDCARDDETECT -1
         #define KILL_PIN 41
       #elif defined(LCD_I2C_VIKI)
         #define BTN_EN1 22  //reverse if the encoder turns the wrong way.
         #define BTN_EN2 7
         #define BTN_ENC -1
-        #define SDSS 53
+        #define LCD_SDSS 53
         #define SDCARDDETECT 49
       #else
         //arduino pin which triggers an piezzo beeper
      #ifdef LCD_I2C_PANELOLU2
        #ifdef MELZI
          #define BTN_ENC 29 //the click switch
-         #define SDSS 30 //to use the SD card reader on the Panelolu2 rather than the melzi board
+         #define LCD_SDSS 30 //to use the SD card reader on the Panelolu2 rather than the melzi board
        #else
          #define BTN_ENC 30 //the click switch
        #endif

Marlin/ultralcd.cpp

     lcd_buttons_update();
 
     #if (SDCARDDETECT > 0)
-    if((IS_SD_INSERTED != lcd_oldcardstatus))
+    if((IS_SD_INSERTED != lcd_oldcardstatus && lcd_detected()))
     {
         lcdDrawUpdate = 2;
         lcd_oldcardstatus = IS_SD_INSERTED;
     if (lcd_status_message_level > 0)
         return;
     strncpy(lcd_status_message, message, LCD_WIDTH);
+
+    size_t i = strlen(lcd_status_message);
+    memset(lcd_status_message + i, ' ', LCD_WIDTH - i);
+    lcd_status_message[LCD_WIDTH] = '\0';
+
     lcdDrawUpdate = 2;
 #ifdef FILAMENT_LCD_DISPLAY
         message_millis=millis();  //get status message to show up for a while
     if (lcd_status_message_level > 0)
         return;
     strncpy_P(lcd_status_message, message, LCD_WIDTH);
+
+    size_t i = strlen(lcd_status_message);
+    memset(lcd_status_message + i, ' ', LCD_WIDTH - i);
+    lcd_status_message[LCD_WIDTH] = '\0';
+
     lcdDrawUpdate = 2;
 #ifdef FILAMENT_LCD_DISPLAY
         message_millis=millis();  //get status message to show up for a while
     lastEncoderBits = enc;
 }
 
+bool lcd_detected(void)
+{
+#if (defined(LCD_I2C_TYPE_MCP23017) || defined(LCD_I2C_TYPE_MCP23008)) && defined(DETECT_DEVICE)
+  return lcd.LcdDetected() == 1;
+#else
+  return true;
+#endif
+}
+
 void lcd_buzz(long duration, uint16_t freq)
 {
 #ifdef LCD_USE_I2C_BUZZER

Marlin/ultralcd.h

   void lcd_setstatuspgm(const char* message);
   void lcd_setalertstatuspgm(const char* message);
   void lcd_reset_alert_level();
+  bool lcd_detected(void);
 
 #ifdef DOGLCD
   extern int lcd_contrast;
   FORCE_INLINE void lcd_buttons_update() {}
   FORCE_INLINE void lcd_reset_alert_level() {}
   FORCE_INLINE void lcd_buzz(long duration,uint16_t freq) {}
+  FORCE_INLINE bool lcd_detected(void) { return true; }
 
   #define LCD_MESSAGEPGM(x) 
   #define LCD_ALERTMESSAGEPGM(x) 

Marlin/ultralcd_implementation_hitachi_HD44780.h

   #include <Wire.h>
   #include <LiquidTWI2.h>
   #define LCD_CLASS LiquidTWI2
-  LCD_CLASS lcd(LCD_I2C_ADDRESS);
+  #if defined(DETECT_DEVICE)
+     LCD_CLASS lcd(LCD_I2C_ADDRESS, 1);
+  #else
+     LCD_CLASS lcd(LCD_I2C_ADDRESS);
+  #endif
   
 #elif defined(LCD_I2C_TYPE_MCP23008)
   #include <Wire.h>
   #include <LiquidTWI2.h>
   #define LCD_CLASS LiquidTWI2
-  LCD_CLASS lcd(LCD_I2C_ADDRESS);  
+  #if defined(DETECT_DEVICE)
+     LCD_CLASS lcd(LCD_I2C_ADDRESS, 1);
+  #else
+     LCD_CLASS lcd(LCD_I2C_ADDRESS);
+  #endif
 
 #elif defined(LCD_I2C_TYPE_PCA8574)
     #include <LiquidCrystal_I2C.h>