An interface to read a PWM input signal, using InterruptIn

Dependents:   PwmIn_HelloWorld PwmIn_ModSerial CHR6dm_reading tugboat ... more

Revision:
1:6d68eb9b6bbb
diff -r 2d3d93d7b204 -r 6d68eb9b6bbb PwmIn.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PwmIn.h	Thu Sep 02 18:17:35 2010 +0000
@@ -0,0 +1,70 @@
+/* mbed PwmIn Library
+ * Copyright (c) 2008-2010, sford
+ *
+ * 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 period();
+    
+    /** Read the current pulsewidth
+     *
+     * @returns the pulsewidth in seconds
+     */
+    float pulsewidth();
+    
+    /** Read the current dutycycle
+     *
+     * @returns the dutycycle as a percentage, represented between 0.0-1.0
+     */
+    float dutycycle();
+
+protected:        
+    void rise();
+    void fall();
+    
+    InterruptIn _p;
+    Timer _t;
+    float _pulsewidth, _period;
+};
+
+#endif