added led.enable (#294)

* added led.enable

* fixed simulator support for led.enable

docs/device/screen.md

@@ -91,3 +91,10 @@ basic.showString("d", 150)
 
 You will not see the LED at position `0,0` lit up because the `show string` function overwrites the whole display buffer.
 
+
+### Pins: P3, P4, P6, P7, P9, P10
+
+These pins are coupled to the LED matrix display, and also it’s associated ambient light sensing mode.
+To disable the display driver feature (which will automatically disable the light sensing feature) use the function [led.enable](/reference/led/enable). 
+
+More information at http://tech.microbit.org/hardware/edgeconnector_ds/ .

docs/reference/led.md

@@ -17,8 +17,9 @@ led.plotAll();
 led.screenshot();
 led.toggleAll();
 led.setDisplayMode(DisplayMode.BackAndWhite);
+led.enable(false)
 ```
 
 ### See Also
 
-[plot](/reference/led/plot), [unplot](/reference/led/unplot), [point](/reference/led/point), [brightness](/reference/led/brightness), [setBrightness](/reference/led/set-brightness), [stopAnimation](/reference/led/stop-animation), [plotBarGraph](/reference/led/plot-bar-graph), [fadeIn](/reference/led/fade-in), [fadeOut](/reference/led/fade-out), [plotAll](/reference/led/plot-all), [screenshot](/reference/led/screenshot), [toggle](/reference/led/toggle), [toggleAll](/reference/led/toggle-all), [setDisplayMode](/reference/led/set-display-mode)
+[plot](/reference/led/plot), [unplot](/reference/led/unplot), [point](/reference/led/point), [brightness](/reference/led/brightness), [setBrightness](/reference/led/set-brightness), [stopAnimation](/reference/led/stop-animation), [plotBarGraph](/reference/led/plot-bar-graph), [fadeIn](/reference/led/fade-in), [fadeOut](/reference/led/fade-out), [plotAll](/reference/led/plot-all), [screenshot](/reference/led/screenshot), [toggle](/reference/led/toggle), [toggleAll](/reference/led/toggle-all), [setDisplayMode](/reference/led/set-display-mode), [enabled](/reference/led/enable)

docs/reference/led/enable.md

@@ -0,0 +1,33 @@
+# Enable
+
+Turns the LED screen on and off
+
+```sig
+led.enable(false);
+```
+
+### Parameters
+
+* ``on`` is a [boolean](/reference/types/boolean) that defines the on/off state of the screen
+
+### Example: Turning off the screen
+
+This program turns off the screen when pressing button ``B``
+
+```typescript
+input.onButtonPressed(Button.B, () => {
+    led.enable(false)
+});
+```
+
+### Pins: P3, P4, P6, P7, P9, P10
+
+These pins are coupled to the LED matrix display, and also it’s associated ambient light sensing mode.
+To disable the display driver feature (which will automatically disable the light sensing feature) call the DAL function ``led.enable(false)``. 
+To turn the display driver back on again later, call ``led.enable(true)``.
+
+More information at http://tech.microbit.org/hardware/edgeconnector_ds/ .
+
+### See also
+
+[unplot](/reference/led/unplot), [point](/reference/led/point), [LED screen](/device/screen)

libs/core/led.cpp

@@ -84,14 +84,24 @@ namespace led {
 
     /**
      * Sets the display mode between black and white and greyscale for rendering LEDs.
-     * @param mode TODO
+     * @param mode mode the display mode in which the screen operates
      */
     //% weight=1 help=led/set-display-mode
-    //% parts="ledmatrix"
+    //% parts="ledmatrix" advanced=true
     void setDisplayMode(DisplayMode_ mode) {
         uBit.display.setDisplayMode((DisplayMode)mode);
     }
 
+    /**
+    * Turns on or off the display    
+    */
+    //% help=led/enable blockId=device_led_enable icon="\uf04d"
+    //% advanced=true parts="ledmatrix"
+    void enable(bool on) {
+        if (on) uBit.display.enable();
+        else uBit.display.disable();
+    }
+
     /**
      * Takes a screenshot of the LED screen and returns an image.
      */

libs/core/shims.d.ts

@@ -488,12 +488,19 @@ declare namespace led {
 
     /**
      * Sets the display mode between black and white and greyscale for rendering LEDs.
-     * @param mode TODO
+     * @param mode mode the display mode in which the screen operates
      */
     //% weight=1 help=led/set-display-mode
-    //% parts="ledmatrix" shim=led::setDisplayMode
+    //% parts="ledmatrix" advanced=true shim=led::setDisplayMode
     function setDisplayMode(mode: DisplayMode): void;
 
+    /**
+     * Turns on or off the display    
+     */
+    //% help=led/enable blockId=device_led_enable icon="\uf04d"
+    //% advanced=true parts="ledmatrix" shim=led::enable
+    function enable(on: boolean): void;
+
     /**
      * Takes a screenshot of the LED screen and returns an image.
      */

sim/state/ledmatrix.ts

@@ -9,6 +9,7 @@ namespace pxsim {
         brigthness = 255;
         displayMode = DisplayMode.bw;
         font: Image = createFont();
+        disabled: boolean;
 
         animationQ: AnimationQueue;
 
@@ -284,4 +285,8 @@ namespace pxsim.led {
         board().ledMatrixState.image.copyTo(0, 5, img, 0);
         return img;
     }
+    export function enable(on: boolean) {
+        board().ledMatrixState.disabled = !on;
+        runtime.queueDisplayUpdate();
+    }
 }

sim/visuals/ledmatrix.ts

@@ -101,8 +101,16 @@ namespace pxsim.visuals {
         }
 
         public updateState() {
-            let bw = this.state.displayMode == pxsim.DisplayMode.bw
+            if (this.state.disabled) {
-            let img = this.state.image;
+                this.leds.forEach((led, i) => {
+                    let sel = (<SVGStylable><any>led)
+                    sel.style.opacity = 0 + "";
+                });
+                return;
+            }
+
+            const bw = this.state.displayMode == pxsim.DisplayMode.bw
+            const img = this.state.image;
             this.leds.forEach((led, i) => {
                 let sel = (<SVGStylable><any>led)
                 let dx = i % this.DRAW_SIZE;

sim/visuals/microbit.ts

@@ -334,12 +334,19 @@ namespace pxsim.visuals {
                 svg.fill(this.buttons[index], btn.pressed ? theme.buttonDown : theme.buttonUp);
             });
 
-            let bw = state.ledMatrixState.displayMode == pxsim.DisplayMode.bw
+            if (state.ledMatrixState.disabled) {
-            let img = state.ledMatrixState.image;
                 this.leds.forEach((led, i) => {
-                let sel = (<SVGStylable><any>led)
+                    const sel = (<SVGStylable><any>led)
+                    sel.style.opacity = "0";
+                })
+            } else {
+                const bw = state.ledMatrixState.displayMode == pxsim.DisplayMode.bw
+                const img = state.ledMatrixState.image;
+                this.leds.forEach((led, i) => {
+                    const sel = (<SVGStylable><any>led)
                     sel.style.opacity = ((bw ? img.data[i] > 0 ? 255 : 0 : img.data[i]) / 255.0) + "";
                 })
+            }
             this.updatePins();
             this.updateTilt();
             this.updateHeading();