PwmIn library by Simon Ford updated and revisited to mbed OS 5.

Revision:
0:3f89bf958c96
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PwmIn.h	Wed Oct 18 00:09:12 2017 +0000
@@ -0,0 +1,79 @@
+/* mbed PwmIn Library UPDATED 
+ * Copyright (c) 2008-2010, sford
+ *------------------------------------------------------------------------------
+ *Rise and Fall libraries were giving  warning: "mbed::InterruptIn::rise(T *, M) 
+ *[with T=PwmIn, M=void (PwmIn::*)()] was declared deprecated". As of that ,
+ *I updated the code with the proper functions.
+ *_p.rise(this, &PwmIn::rise); changed with _p.rise(callback(this, &PwmIn::rise));
+ *_p.fall(this, &PwmIn::rise); changed with _p.fall(callback(this, &PwmIn::rise));
+ *I also changed some methods names  beacause I think they could generate some 
+ *confusion while progamming together with PwmOut. 
+ *-------------------------------------------------------------dpalombi
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+ 
+#ifndef MBED_PWMIN_H
+#define MBED_PWMIN_H
+ 
+#include "mbed.h"
+ 
+/** PwmIn class to read PWM inputs
+ * 
+ * Uses InterruptIn to measure the changes on the input
+ * and record the time they occur
+ *
+ * @note uses InterruptIn, so not available on p19/p20
+ */
+class PwmIn {
+public:
+    /** Create a PwmIn
+     *
+     * @param p The pwm input pin (must support InterruptIn)
+     */ 
+    PwmIn(PinName p);
+    
+    /** Read the current period
+     *
+     * @returns the period in seconds
+     */
+    float periodIn();
+    
+    /** Read the current pulsewidth
+     *
+     * @returns the pulsewidth in seconds
+     */
+    float pulsewidthIn();
+    
+    /** Read the current dutycycle
+     *
+     * @returns the dutycycle as a percentage, represented between 0.0-1.0
+     */
+    float dutycycleIn();
+ 
+protected:        
+    void rise();
+    void fall();
+    
+    InterruptIn _p;
+    Timer _t;
+    float _pulsewidth, _period;
+};
+ 
+#endif
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