don't burn so much cpu spinning in loop()

src/main.ino

@@ -371,8 +371,10 @@ void setup()
 
 void loop()
 {
+  uint32_t msecstosleep = 1000 * 30; // How long can we sleep before we again need to service the main loop?
+
   gps.loop();
-  screen_loop();
+  msecstosleep = min(screen_loop(), msecstosleep);
   service.loop();
   loopBLE();
 
@@ -428,5 +430,6 @@ void loop()
 
   // No GPS lock yet, let the OS put the main CPU in low power mode for 100ms (or until another interrupt comes in)
   // i.e. don't just keep spinning in loop as fast as we can.
-  //delay(100);
+  DEBUG_MSG("msecs %d\n", msecstosleep);
+  delay(msecstosleep);
 }

src/screen.cpp

@@ -259,10 +259,10 @@ void screen_setup()
 #endif
 }
 
-void screen_loop()
+uint32_t screen_loop()
 {
     if (!disp)
-        return;
+        return 30 * 1000;
 
 #ifdef T_BEAM_V10
     if (axp192_found && pmu_irq)
@@ -295,11 +295,17 @@ void screen_loop()
 #endif
     static bool showingBootScreen = true;
 
-    ui.update();
+
+    
+
+    uint32_t msecstosleep =     ui.update();
 
     // Once we finish showing the bootscreen, remove it from the loop
     if (showingBootScreen && ui.getUiState()->currentFrame == 1)
     {
         ui.setFrames(nonBootFrames, frameCount - 1);
     }
+
+    // If we are scrolling do 30fps, otherwise just 1 fps (to save CPU)
+    return (ui.getUiState()->frameState == IN_TRANSITION ? 10 : 500);
 }

src/screen.h

@@ -1,4 +1,8 @@
 #pragma once
 
 void screen_print(const char * text);
-void screen_loop(), screen_setup(), screen_on(), screen_off(), screen_show_logo();
+
+/// @return how many msecs can we sleep before we want service again
+uint32_t screen_loop();
+
+void screen_setup(), screen_on(), screen_off(), screen_show_logo();