PwmIn.cpp

00001 /* mbed PwmIn Library
00002  * Copyright (c) 2008-2010, sford
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022  
00023 #include "PwmIn.h"
00024 
00025 PwmIn::PwmIn(PinName p) : _p(p) {
00026     _p.mode(PullNone);
00027     _p.rise(this, &PwmIn::rise);
00028     _p.fall(this, &PwmIn::fall);
00029     _period = 0.0;
00030     _pulsewidth = 0.0;
00031     _temp_pulsewidth = 0.0;
00032     _t.start();
00033 }
00034 
00035 float PwmIn::period() {
00036     return _period;
00037 }
00038 
00039 float PwmIn::pulsewidth() {
00040     return _pulsewidth;
00041 }
00042 
00043 float PwmIn::dutycycle() {
00044     if(_t.read_ms()<100){
00045     return (_pulsewidth%_period) /((float) _period);}   
00046     else return 0;
00047 }
00048 
00049 void PwmIn::rise() {
00050     _period = _t.read_us();
00051     _t.reset();
00052 }
00053 
00054 void PwmIn::fall() {
00055     _temp_pulsewidth = _t.read_us();
00056     if(_temp_pulsewidth != 0) _pulsewidth = _temp_pulsewidth;
00057 }