Keep blinking limited to LCD_UPDATE_INTERVAL

Marlin/dogm_lcd_implementation.h

@@ -304,9 +304,11 @@ static void _draw_heater_status(int x, int heater) {
 static void lcd_implementation_status_screen() {
   u8g.setColorIndex(1); // black on white
 
+  bool blink = lcd_blink();
+
   #if HAS_FAN0
     // Symbols menu graphics, animated fan
-    u8g.drawBitmapP(9, 1, STATUS_SCREENBYTEWIDTH, STATUS_SCREENHEIGHT, (blink % 2) && fanSpeeds[0] ? status_screen0_bmp : status_screen1_bmp);
+    u8g.drawBitmapP(9, 1, STATUS_SCREENBYTEWIDTH, STATUS_SCREENHEIGHT, blink && fanSpeeds[0] ? status_screen0_bmp : status_screen1_bmp);
   #endif
 
   #if ENABLED(SDSUPPORT)
@@ -375,18 +377,19 @@ static void lcd_implementation_status_screen() {
   #endif
   u8g.setColorIndex(0); // white on black
   u8g.setPrintPos(2, XYZ_BASELINE);
-  if (blink & 1)
+  if (blink)
     lcd_printPGM(PSTR("X"));
   else {
     if (!axis_homed[X_AXIS])
       lcd_printPGM(PSTR("?"));
-    else
+    else {
       #if DISABLED(DISABLE_REDUCED_ACCURACY_WARNING)
         if (!axis_known_position[X_AXIS])
           lcd_printPGM(PSTR(" "));
         else
       #endif
       lcd_printPGM(PSTR("X"));
+    }
   }
   u8g.drawPixel(8, XYZ_BASELINE - 5);
   u8g.drawPixel(8, XYZ_BASELINE - 3);
@@ -394,18 +397,19 @@ static void lcd_implementation_status_screen() {
   lcd_print(ftostr31ns(current_position[X_AXIS]));
 
   u8g.setPrintPos(43, XYZ_BASELINE);
-  if (blink & 1)
+  if (blink)
     lcd_printPGM(PSTR("Y"));
   else {
     if (!axis_homed[Y_AXIS])
       lcd_printPGM(PSTR("?"));
-    else
+    else {
       #if DISABLED(DISABLE_REDUCED_ACCURACY_WARNING)
         if (!axis_known_position[Y_AXIS])
           lcd_printPGM(PSTR(" "));
         else
       #endif
       lcd_printPGM(PSTR("Y"));
+    }
   }
   u8g.drawPixel(49, XYZ_BASELINE - 5);
   u8g.drawPixel(49, XYZ_BASELINE - 3);
@@ -413,18 +417,19 @@ static void lcd_implementation_status_screen() {
   lcd_print(ftostr31ns(current_position[Y_AXIS]));
 
   u8g.setPrintPos(83, XYZ_BASELINE);
-  if (blink & 1)
+  if (blink)
     lcd_printPGM(PSTR("Z"));
   else {
     if (!axis_homed[Z_AXIS])
       lcd_printPGM(PSTR("?"));
-    else
+    else {
       #if DISABLED(DISABLE_REDUCED_ACCURACY_WARNING)
         if (!axis_known_position[Z_AXIS])
           lcd_printPGM(PSTR(" "));
         else
       #endif
       lcd_printPGM(PSTR("Z"));
+    }
   }
   u8g.drawPixel(89, XYZ_BASELINE - 5);
   u8g.drawPixel(89, XYZ_BASELINE - 3);

Marlin/ultralcd.cpp

@@ -48,8 +48,6 @@
   #define ENCODER_DIRECTION_MENUS() ;
 #endif
 
-uint8_t blink = 0; // Variable for animation
-
 int8_t encoderDiff; // updated from interrupt context and added to encoderPosition every LCD update
 
 bool encoderRateMultiplierEnabled;
@@ -1807,6 +1805,16 @@ int lcd_strlen_P(const char* s) {
   return j;
 }
 
+bool lcd_blink() {
+  static uint8_t blink = 0;
+  static millis_t next_blink_ms = 0;
+  if (millis() >= next_blink_ms) {
+    blink ^= 0xFF;
+    next_blink_ms = millis() + LCD_UPDATE_INTERVAL - 50;
+  }
+  return blink != 0;
+}
+
 /**
  * Update the LCD, read encoder buttons, etc.
  *   - Read button states
@@ -1923,25 +1931,23 @@ void lcd_update() {
         lcd_status_update_delay--;
       }
     }
-    #if ENABLED(DOGLCD)  // Changes due to different driver architecture of the DOGM display
-        if (lcdDrawUpdate) {
-          blink++;     // Variable for animation and alive dot
-          u8g.firstPage();
-          do {
-            lcd_setFont(FONT_MENU);
-            u8g.setPrintPos(125, 0);
-            if (blink & 1) u8g.setColorIndex(1); else u8g.setColorIndex(0); // Set color for the alive dot
-            u8g.drawPixel(127, 63); // draw alive dot
-            u8g.setColorIndex(1); // black on white
-            (*currentMenu)();
-          } while (u8g.nextPage());
-        }
-    #else
-      if (lcdDrawUpdate) {
-        blink++;     // Variable for animation
+
+    if (lcdDrawUpdate) {
+      #if ENABLED(DOGLCD)  // Changes due to different driver architecture of the DOGM display
+        bool blink = lcd_blink();
+        u8g.firstPage();
+        do {
+          lcd_setFont(FONT_MENU);
+          u8g.setPrintPos(125, 0);
+          u8g.setColorIndex(blink ? 1 : 0); // Set color for the alive dot
+          u8g.drawPixel(127, 63); // draw alive dot
+          u8g.setColorIndex(1); // black on white
+          (*currentMenu)();
+        } while (u8g.nextPage());
+      #else
         (*currentMenu)();
-      }
-    #endif
+      #endif
+    }
 
     #if ENABLED(LCD_HAS_STATUS_INDICATORS)
       lcd_implementation_update_indicators();
@@ -1963,8 +1969,7 @@ void lcd_update() {
 
     #endif // ULTIPANEL
 
-    if (lcdDrawUpdate == 2) lcd_implementation_clear();
-    if (lcdDrawUpdate) lcdDrawUpdate--;
+    if (lcdDrawUpdate && --lcdDrawUpdate) lcd_implementation_clear();
     next_lcd_update_ms = ms + LCD_UPDATE_INTERVAL;
   }
 }

Marlin/ultralcd.h

@@ -76,15 +76,13 @@
 
   extern bool cancel_heatup;
 
-  extern uint8_t blink; // Variable for animation
-
   #if ENABLED(FILAMENT_LCD_DISPLAY)
     extern millis_t previous_lcd_status_ms;
   #endif
   void lcd_quick_feedback(); // Audible feedback for a button click - could also be visual
   bool lcd_clicked();
-
   void lcd_ignore_click(bool b=true);
+  bool lcd_blink();
 
   #if ENABLED(NEWPANEL)
     #define EN_C (_BV(BLEN_C))

Marlin/ultralcd_implementation_hitachi_HD44780.h

@@ -626,6 +626,8 @@ static void lcd_implementation_status_screen() {
 
   #if LCD_HEIGHT > 2
 
+    bool blink = lcd_blink();
+
     #if LCD_WIDTH < 20
 
       #if ENABLED(SDSUPPORT)
@@ -654,7 +656,7 @@ static void lcd_implementation_status_screen() {
         // When axis is homed but axis_known_position is false the axis letters are blinking 'X' <-> ' '.
         // When everything is ok you see a constant 'X'.
 
-        if (blink & 1)
+        if (blink)
           lcd_printPGM(PSTR("X"));
         else {
           if (!axis_homed[X_AXIS])
@@ -671,7 +673,7 @@ static void lcd_implementation_status_screen() {
         lcd.print(ftostr4sign(current_position[X_AXIS]));
 
         lcd_printPGM(PSTR(" "));
-        if (blink & 1)
+        if (blink)
           lcd_printPGM(PSTR("Y"));
         else {
           if (!axis_homed[Y_AXIS])
@@ -691,7 +693,7 @@ static void lcd_implementation_status_screen() {
     #endif // LCD_WIDTH >= 20
 
     lcd.setCursor(LCD_WIDTH - 8, 1);
-    if (blink & 1)
+    if (blink)
       lcd_printPGM(PSTR("Z"));
     else {
       if (!axis_homed[Z_AXIS])