diff --git a/docs/reference/input.md b/docs/reference/input.md
index c3bc2337..cc067255 100644
--- a/docs/reference/input.md
+++ b/docs/reference/input.md
@@ -21,6 +21,7 @@ input.lightLevel();
 input.rotation(Rotation.Pitch);
 input.magneticForce(Dimension.X);
 input.runningTime();
+input.runningTimeMicros();
 input.setAccelerometerRange(AcceleratorRange.OneG);
 ```
 
diff --git a/docs/reference/input/running-time-micros.md b/docs/reference/input/running-time-micros.md
new file mode 100644
index 00000000..413cf4ef
--- /dev/null
+++ b/docs/reference/input/running-time-micros.md
@@ -0,0 +1,17 @@
+# Running Time Micros
+
+Find how long it has been since the program started in micro-seconds.
+
+```sig
+input.runningTimeMicros();
+```
+
+## Returns
+
+* the [Number](/types/number) of microseconds since the program started.
+(One second is 1000000 microseconds.)
+
+## See also
+
+[show number](/reference/basic/show-number), [pause](/reference/basic/pause)
+
diff --git a/docs/reference/input/running-time.md b/docs/reference/input/running-time.md
index db209d16..099fb640 100644
--- a/docs/reference/input/running-time.md
+++ b/docs/reference/input/running-time.md
@@ -1,6 +1,6 @@
 # Running Time
 
-Find how long it has been since the program started.
+Find how long it has been since the program started in milli-seconds.
 
 ```sig
 input.runningTime();
diff --git a/libs/core/_locales/core-jsdoc-strings.json b/libs/core/_locales/core-jsdoc-strings.json
index c1adf164..8ea340a1 100644
--- a/libs/core/_locales/core-jsdoc-strings.json
+++ b/libs/core/_locales/core-jsdoc-strings.json
@@ -179,6 +179,7 @@
   "input.rotation": "The pitch or roll of the device, rotation along the ``x-axis`` or ``y-axis``, in degrees.",
   "input.rotation|param|kind": "TODO",
   "input.runningTime": "Gets the number of milliseconds elapsed since power on.",
+  "input.runningTimeMicros": "Gets the number of microseconds elapsed since power on.",
   "input.setAccelerometerRange": "Sets the accelerometer sample range in gravities.",
   "input.setAccelerometerRange|param|range": "a value describe the maximum strengh of acceleration measured",
   "input.temperature": "Gets the temperature in Celsius degrees (°C).",
diff --git a/libs/core/_locales/core-strings.json b/libs/core/_locales/core-strings.json
index fb3f9dfe..859ca87e 100644
--- a/libs/core/_locales/core-strings.json
+++ b/libs/core/_locales/core-strings.json
@@ -268,6 +268,7 @@
   "input.onPinReleased|block": "on pin %NAME|released",
   "input.pinIsPressed|block": "pin %NAME|is pressed",
   "input.rotation|block": "rotation (°)|%NAME",
+  "input.runningTimeMicros|block": "running time (micros)",
   "input.runningTime|block": "running time (ms)",
   "input.setAccelerometerRange|block": "set accelerometer|range %range",
   "input.temperature|block": "temperature (°C)",
diff --git a/libs/core/game.ts b/libs/core/game.ts
index 205ee9f5..97ad0b89 100644
--- a/libs/core/game.ts
+++ b/libs/core/game.ts
@@ -73,16 +73,11 @@ namespace game {
             _backgroundAnimation = true;
             control.inBackground(() => {
                 led.stopAnimation();
-                const dm = led.displayMode();
-                if (dm != DisplayMode.BackAndWhite)
-                    led.setDisplayMode(DisplayMode.BackAndWhite);
                 basic.showAnimation(`0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 0 0 0 1 0 0 0 0 0
     0 0 0 0 0 0 0 1 0 0 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0
     0 0 1 0 0 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
     0 0 0 0 0 0 0 1 0 0 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0
     0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 0 0 0 1 0 0 0 0 0`, 20);
-                if (dm != DisplayMode.BackAndWhite)
-                    led.setDisplayMode(dm);
                 _backgroundAnimation = false;
             });
         }
@@ -125,7 +120,6 @@ namespace game {
             unplugEvents();
             led.stopAnimation();
             led.setBrightness(255);
-            led.setDisplayMode(DisplayMode.BackAndWhite);
             while (true) {
                 for (let i = 0; i < 8; i++) {
                     basic.clearScreen();
@@ -777,6 +771,9 @@ namespace game {
             _sprites[i]._plot(now);
         }
         _img.plotImage(0);
+        // restore previous display mode
+        if (dm != DisplayMode.Greyscale)
+            led.setDisplayMode(dm);
     }
 
     /**
diff --git a/libs/core/input.cpp b/libs/core/input.cpp
index d6932473..63dbccf9 100644
--- a/libs/core/input.cpp
+++ b/libs/core/input.cpp
@@ -339,13 +339,23 @@ namespace input {
     /**
      * Gets the number of milliseconds elapsed since power on.
      */
-    //% help=input/running-time weight=50
+    //% help=input/running-time weight=50 blockGap=8
     //% blockId=device_get_running_time block="running time (ms)"
     //% advanced=true
     int runningTime() {
         return system_timer_current_time();
     }
 
+    /**
+     * Gets the number of microseconds elapsed since power on.
+     */
+    //% help=input/running-time-micros weight=49
+    //% blockId=device_get_running_time_micros block="running time (micros)"
+    //% advanced=true
+    int runningTimeMicros() {
+        return system_timer_current_time_us();
+    }
+
     /**
      * Obsolete, compass calibration is automatic.
      */
diff --git a/libs/core/shims.d.ts b/libs/core/shims.d.ts
index f5fae3e3..9001c17b 100644
--- a/libs/core/shims.d.ts
+++ b/libs/core/shims.d.ts
@@ -332,11 +332,19 @@ declare namespace input {
     /**
      * Gets the number of milliseconds elapsed since power on.
      */
-    //% help=input/running-time weight=50
+    //% help=input/running-time weight=50 blockGap=8
     //% blockId=device_get_running_time block="running time (ms)"
     //% advanced=true shim=input::runningTime
     function runningTime(): number;
 
+    /**
+     * Gets the number of microseconds elapsed since power on.
+     */
+    //% help=input/running-time-micros weight=49
+    //% blockId=device_get_running_time_micros block="running time (micros)"
+    //% advanced=true shim=input::runningTimeMicros
+    function runningTimeMicros(): number;
+
     /**
      * Obsolete, compass calibration is automatic.
      */
diff --git a/package.json b/package.json
index f8b4fd4a..6e1bb1d3 100644
--- a/package.json
+++ b/package.json
@@ -38,6 +38,6 @@
     "semantic-ui-less": "^2.2.4"
   },
   "dependencies": {
-    "pxt-core": "0.14.1"
+    "pxt-core": "0.14.3"
   }
 }
diff --git a/sim/state/misc.ts b/sim/state/misc.ts
index cc16ed92..597b4720 100644
--- a/sim/state/misc.ts
+++ b/sim/state/misc.ts
@@ -86,6 +86,10 @@ namespace pxsim.input {
         return runtime.runningTime();
     }
 
+    export function runningTimeMicros(): number {
+        return runtime.runningTimeUs();
+    }
+
     export function calibrateCompass() {
         // device calibrates...
     }