PwmIn.h

00001 
00002 #ifndef MBED_PWMIN_H
00003 #define MBED_PWMIN_H
00004  
00005 #include "mbed.h"
00006  
00007 /** PwmIn class to read PWM inputs
00008  * 
00009  * Uses InterruptIn to measure the changes on the input
00010  * and record the time they occur
00011  *
00012  * @note uses InterruptIn, so not available on p19/p20
00013  */
00014 class PwmIn {
00015 public:
00016     /** Create a PwmIn
00017      *
00018      * @param p The pwm input pin (must support InterruptIn)
00019      */ 
00020     PwmIn(PinName p, float dutyMin, float dutyMax) ;
00021     
00022     /** Read the current period
00023      *
00024      * @returns the period in seconds
00025      */
00026     float period();
00027     
00028     /** Read the current pulsewidth
00029      *
00030      * @returns the pulsewidth in seconds
00031      */
00032     float pulsewidth();
00033     
00034     /** Read the current dutycycle
00035      *
00036      * @returns the dutycycle as a percentage, represented between 0.0-1.0
00037      */
00038     float dutycycle();
00039     
00040     float dutycyclescaledup();
00041  
00042 protected:        
00043     void rise();
00044     void fall();
00045     
00046     InterruptIn _p;
00047     Timer _t;
00048     int _pulsewidth, _period;
00049     int _tmp;
00050     float _dutyMin, _dutyMax, _dutyDelta;
00051     
00052     bool _risen;
00053 };
00054  
00055 #endif