adding pins.pulseIn API

libs/microbit/pins.cpp

@@ -160,11 +160,32 @@ namespace pins {
     */
     //% help=pins/pulse-duration
     //% blockId=pins_pulse_duration block="pulse duration (µs)"
-    //% weight=21
+    //% weight=21 blockGap=8
     int pulseDuration() {
         return pxt::lastEvent.timestamp;
     }
 
+    /**
+    * Returns the duration of a pulse in microseconds
+    * @param name the pin which measures the pulse
+    * @param value the value of the pulse (default high)
+    */    
+    //% blockId="pins_pulse_in" block="pulse in (µs)|pin %name"
+    //% weight=20
+    int pulseIn(DigitalPin name, PulseValue value) {
+        MicroBitPin* pin = getPin((int)name);
+        if (!pin) return 0;
+
+        int pulse = value == PulseValue::High ? 1 : 0;
+        while(pin->getDigitalValue() != pulse);
+
+        uint64_t start =  system_timer_current_time_us();       
+        while(pin->getDigitalValue() == pulse);
+        uint64_t end =  system_timer_current_time_us();       
+        
+        return end - start;         
+    }
+
     /**
      * Writes a value to the servo, controlling the shaft accordingly. On a standard servo, this will set the angle of the shaft (in degrees), moving the shaft to that orientation. On a continuous rotation servo, this will set the speed of the servo (with ``0`` being full-speed in one direction, ``180`` being full speed in the other, and a value near ``90`` being no movement).
      * @param name pin to write to

libs/microbit/pins.ts

@@ -11,7 +11,7 @@ namespace pins {
      * @param toLow the lower bound of the value's target range
      * @param toHigh the upper bound of the value's target range, eg: 4
      */
-    //% help=pins/map weight=22
+    //% help=pins/map weight=23
     //% blockId=math_map block="map %value|from low %fromLow|from high %fromHigh|to low %toLow|to high %toHigh"
     export function map(value: number, fromLow: number, fromHigh: number, toLow: number, toHigh: number): number {
         return ((value - fromLow) * (toHigh - toLow)) / (fromHigh - fromLow) + toLow;

libs/microbit/shims.d.ts

@@ -514,9 +514,18 @@ declare namespace pins {
      */
     //% help=pins/pulse-duration
     //% blockId=pins_pulse_duration block="pulse duration (µs)"
-    //% weight=21 shim=pins::pulseDuration
+    //% weight=21 blockGap=8 shim=pins::pulseDuration
     function pulseDuration(): number;
 
+    /**
+     * Returns the duration of a pulse in microseconds
+     * @param name the pin which measures the pulse
+     * @param value the value of the pulse (default high)
+     */
+    //% blockId="pins_pulse_in" block="pulse in (µs)|pin %name"
+    //% weight=20 shim=pins::pulseIn
+    function pulseIn(name: DigitalPin, value: PulseValue): number;
+
     /**
      * Writes a value to the servo, controlling the shaft accordingly. On a standard servo, this will set the angle of the shaft (in degrees), moving the shaft to that orientation. On a continuous rotation servo, this will set the speed of the servo (with ``0`` being full-speed in one direction, ``180`` being full speed in the other, and a value near ``90`` being no movement).
      * @param name pin to write to