Federico Centeno / SoftPWM

The PWM output by software. Can be output to any pin. It can be used to replace the Pwmout.

Fork of SoftPWM by syouichi imamori

SoftPWM.cpp@0:7918ce37626c, 2013-10-23 (annotated)

Committer:
komaida424
Date:
Wed Oct 23 19:31:14 2013 +0000
Revision:
0:7918ce37626c
The PWM output by software. Can be output to any pin. It can be used to replace the Pwmout.

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Who changed what in which revision?

UserRevisionLine numberNew contents of line
komaida424 0:7918ce37626c 1 #include "mbed.h"
komaida424 0:7918ce37626c 2 #include "InterruptIn.h"
komaida424 0:7918ce37626c 3 #include "SoftPWM.h"
komaida424 0:7918ce37626c 4
komaida424 0:7918ce37626c 5 SoftPWM::SoftPWM(PinName _outpin,bool _positive) : pulse(_outpin) //constructa
komaida424 0:7918ce37626c 6 {
komaida424 0:7918ce37626c 7 if ( _positive )
komaida424 0:7918ce37626c 8 pulse = 0;
komaida424 0:7918ce37626c 9 else
komaida424 0:7918ce37626c 10 pulse = 1;
komaida424 0:7918ce37626c 11 positive = _positive;
komaida424 0:7918ce37626c 12 interval = 0.02;
komaida424 0:7918ce37626c 13 width = 0;
komaida424 0:7918ce37626c 14 start();
komaida424 0:7918ce37626c 15 }
komaida424 0:7918ce37626c 16
komaida424 0:7918ce37626c 17 float SoftPWM::read()
komaida424 0:7918ce37626c 18 {
komaida424 0:7918ce37626c 19 if ( width <= 0.0 ) return 0.0;
komaida424 0:7918ce37626c 20 if ( width > 1.0 ) return 1.0;
komaida424 0:7918ce37626c 21 return width / interval;
komaida424 0:7918ce37626c 22 }
komaida424 0:7918ce37626c 23
komaida424 0:7918ce37626c 24 void SoftPWM::write(float duty)
komaida424 0:7918ce37626c 25 {
komaida424 0:7918ce37626c 26 width = interval * duty;
komaida424 0:7918ce37626c 27 if ( duty <= 0.0 ) width = 0.0;
komaida424 0:7918ce37626c 28 if ( duty > 1.0 ) width = interval;
komaida424 0:7918ce37626c 29 }
komaida424 0:7918ce37626c 30
komaida424 0:7918ce37626c 31 void SoftPWM::start()
komaida424 0:7918ce37626c 32 {
komaida424 0:7918ce37626c 33 _ticker.attach(this,&SoftPWM::TickerInterrapt,interval);
komaida424 0:7918ce37626c 34 }
komaida424 0:7918ce37626c 35
komaida424 0:7918ce37626c 36 void SoftPWM::stop()
komaida424 0:7918ce37626c 37 {
komaida424 0:7918ce37626c 38 _ticker.detach();
komaida424 0:7918ce37626c 39 if ( positive )
komaida424 0:7918ce37626c 40 pulse = 0;
komaida424 0:7918ce37626c 41 else
komaida424 0:7918ce37626c 42 pulse = 1;
komaida424 0:7918ce37626c 43 wait(width);
komaida424 0:7918ce37626c 44 }
komaida424 0:7918ce37626c 45
komaida424 0:7918ce37626c 46 void SoftPWM::period(float _period)
komaida424 0:7918ce37626c 47 {
komaida424 0:7918ce37626c 48 interval = _period;
komaida424 0:7918ce37626c 49 start();
komaida424 0:7918ce37626c 50 }
komaida424 0:7918ce37626c 51
komaida424 0:7918ce37626c 52 void SoftPWM::period_ms(int _period)
komaida424 0:7918ce37626c 53 {
komaida424 0:7918ce37626c 54 period((float)_period / 1000);
komaida424 0:7918ce37626c 55 start();
komaida424 0:7918ce37626c 56 }
komaida424 0:7918ce37626c 57
komaida424 0:7918ce37626c 58 void SoftPWM::period_us(int _period)
komaida424 0:7918ce37626c 59 {
komaida424 0:7918ce37626c 60 period((float)_period / 1000000);
komaida424 0:7918ce37626c 61 start();
komaida424 0:7918ce37626c 62 }
komaida424 0:7918ce37626c 63
komaida424 0:7918ce37626c 64 void SoftPWM::pulsewidth(float _width)
komaida424 0:7918ce37626c 65 {
komaida424 0:7918ce37626c 66 width = _width;
komaida424 0:7918ce37626c 67 if ( width < 0.0 ) width = 0.0;
komaida424 0:7918ce37626c 68 }
komaida424 0:7918ce37626c 69
komaida424 0:7918ce37626c 70 void SoftPWM::pulsewidth_ms(int _width)
komaida424 0:7918ce37626c 71 {
komaida424 0:7918ce37626c 72 pulsewidth((float)_width / 1000);
komaida424 0:7918ce37626c 73 }
komaida424 0:7918ce37626c 74
komaida424 0:7918ce37626c 75 void SoftPWM::pulsewidth_us(int _width)
komaida424 0:7918ce37626c 76 {
komaida424 0:7918ce37626c 77 pulsewidth((float)_width / 1000000);
komaida424 0:7918ce37626c 78 }
komaida424 0:7918ce37626c 79
komaida424 0:7918ce37626c 80 void SoftPWM::TickerInterrapt()
komaida424 0:7918ce37626c 81 {
komaida424 0:7918ce37626c 82 if ( width <= 0 ) return;
komaida424 0:7918ce37626c 83 _timeout.attach(this,&SoftPWM::end,width);
komaida424 0:7918ce37626c 84 if ( positive )
komaida424 0:7918ce37626c 85 pulse = 1;
komaida424 0:7918ce37626c 86 else
komaida424 0:7918ce37626c 87 pulse = 0;
komaida424 0:7918ce37626c 88 }
komaida424 0:7918ce37626c 89
komaida424 0:7918ce37626c 90 void SoftPWM::end()
komaida424 0:7918ce37626c 91 {
komaida424 0:7918ce37626c 92 if ( positive )
komaida424 0:7918ce37626c 93 pulse = 0;
komaida424 0:7918ce37626c 94 else
komaida424 0:7918ce37626c 95 pulse = 1;
komaida424 0:7918ce37626c 96 // _timeout.detach();
komaida424 0:7918ce37626c 97 }
komaida424 0:7918ce37626c 98 ;
komaida424 0:7918ce37626c 99