SoftPWM.cpp

00001 #include "mbed.h"
00002 #include "InterruptIn.h"
00003 #include "SoftPWM.h"
00004 
00005 SoftPWM::SoftPWM(PinName _outpin,bool _positive) : pulse(_outpin)     //constructa  
00006 {
00007     if ( _positive )
00008         pulse = 0;
00009     else
00010         pulse = 1;
00011     positive = _positive;
00012     interval = 0.02;
00013     width = 0;
00014     start(); 
00015 }
00016 
00017 double SoftPWM::read()
00018 {
00019     if ( width <= 0.0 ) return 0.0;
00020     if ( width > 1.0 )  return 1.0;
00021     return width / interval;    
00022 }
00023 
00024 void SoftPWM::write(double duty)
00025 {
00026     width = interval * duty;
00027     if ( duty <= 0.0 ) width =  0.0;
00028     if ( duty > 1.0 )  width =  interval;
00029 }
00030 
00031 void SoftPWM::start()
00032 {
00033     _ticker.attach(callback(this,&SoftPWM::TickerInterrapt),interval);
00034 }
00035 
00036 void SoftPWM::stop()
00037 {
00038     _ticker.detach();
00039     if ( positive )
00040         pulse = 0;
00041     else
00042         pulse = 1;
00043     wait(width);
00044 }
00045 
00046 void SoftPWM::period(double _period)
00047 {
00048     interval = _period;
00049     start();
00050 }
00051 
00052 void SoftPWM::period_ms(int _period)
00053 {
00054     period((double)_period / 1000);
00055     start();
00056 }
00057 
00058 void SoftPWM::period_us(int _period)
00059 {
00060     period((double)_period / 1000000);
00061     start();
00062 }
00063 
00064 void SoftPWM::pulsewidth(double _width)
00065 {
00066     width = _width;
00067    if ( width < 0.0 ) width = 0.0;
00068 }
00069 
00070 void SoftPWM::pulsewidth_ms(int _width)
00071 {
00072      pulsewidth((double)_width / 1000);
00073 }
00074 
00075 void SoftPWM::pulsewidth_us(int _width)
00076 {
00077     pulsewidth((double)_width / 1000000);
00078 }
00079 
00080 void SoftPWM::TickerInterrapt()
00081 { 
00082     if ( width <= 0 ) return;
00083     _timeout.attach(callback(this,&SoftPWM::end),width);
00084     if ( positive )
00085         pulse = 1;
00086     else
00087         pulse = 0;    
00088 }
00089 
00090 void SoftPWM::end()
00091 {
00092     if ( positive )
00093         pulse = 0;
00094     else
00095         pulse = 1;    
00096 //    _timeout.detach();
00097 }
00098 ;
00099