Revision 0:7918ce37626c, committed 2013-10-23

Comitter:

komaida424

Date:

Wed Oct 23 19:31:14 2013 +0000

Commit message:

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

Changed in this revision

diff -r 000000000000 -r 7918ce37626c SoftPWM.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftPWM.cpp	Wed Oct 23 19:31:14 2013 +0000
@@ -0,0 +1,99 @@
+#include "mbed.h"
+#include "InterruptIn.h"
+#include "SoftPWM.h"
+
+SoftPWM::SoftPWM(PinName _outpin,bool _positive) : pulse(_outpin)     //constructa  
+{
+    if ( _positive )
+        pulse = 0;
+    else
+        pulse = 1;
+    positive = _positive;
+    interval = 0.02;
+    width = 0;
+    start(); 
+}
+
+float SoftPWM::read()
+{
+    if ( width <= 0.0 ) return 0.0;
+    if ( width > 1.0 )  return 1.0;
+    return width / interval;    
+}
+
+void SoftPWM::write(float duty)
+{
+    width = interval * duty;
+    if ( duty <= 0.0 ) width =  0.0;
+    if ( duty > 1.0 )  width =  interval;
+}
+
+void SoftPWM::start()
+{
+    _ticker.attach(this,&SoftPWM::TickerInterrapt,interval);
+}
+
+void SoftPWM::stop()
+{
+    _ticker.detach();
+    if ( positive )
+        pulse = 0;
+    else
+        pulse = 1;
+    wait(width);
+}
+
+void SoftPWM::period(float _period)
+{
+    interval = _period;
+    start();
+}
+
+void SoftPWM::period_ms(int _period)
+{
+    period((float)_period / 1000);
+    start();
+}
+
+void SoftPWM::period_us(int _period)
+{
+    period((float)_period / 1000000);
+    start();
+}
+
+void SoftPWM::pulsewidth(float _width)
+{
+    width = _width;
+   if ( width < 0.0 ) width = 0.0;
+}
+
+void SoftPWM::pulsewidth_ms(int _width)
+{
+     pulsewidth((float)_width / 1000);
+}
+
+void SoftPWM::pulsewidth_us(int _width)
+{
+    pulsewidth((float)_width / 1000000);
+}
+
+void SoftPWM::TickerInterrapt()
+{ 
+    if ( width <= 0 ) return;
+    _timeout.attach(this,&SoftPWM::end,width);
+    if ( positive )
+        pulse = 1;
+    else
+        pulse = 0;    
+}
+
+void SoftPWM::end()
+{
+    if ( positive )
+        pulse = 0;
+    else
+        pulse = 1;    
+//    _timeout.detach();
+}
+;
+

diff -r 000000000000 -r 7918ce37626c SoftPWM.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftPWM.h	Wed Oct 23 19:31:14 2013 +0000
@@ -0,0 +1,45 @@
+#ifndef SoftPWM_H
+#define SoftPWM_H
+#define POSITIVE true
+#define NEGATIVE false
+
+#include "mbed.h"
+
+class SoftPWM  
+{
+private:
+    Timeout _timeout;
+    Ticker _ticker;
+    void end();
+    DigitalOut pulse;
+    bool positive;
+    void TickerInterrapt();
+    float width;
+    float interval;
+public:
+    SoftPWM(PinName,bool mode=true); 
+//    void attach_us(int);
+    void start();
+    void write(float);
+    float read();
+    void pulsewidth(float);
+    void pulsewidth_ms(int);
+    void pulsewidth_us(int);
+    void period(float);
+    void period_ms(int);
+    void period_us(int);
+    void stop();
+    operator float()  { 
+        if ( width <= 0.0 ) return 0.0;
+        if ( width > 1.0 )  return 1.0;
+        return width / interval;
+    }
+    SoftPWM& operator=(float duty)  {
+        width = interval * duty;
+        if ( duty <= 0.0 ) width =  0.0;
+        if ( duty > 1.0 )  width =  interval;
+        return *this;
+    }
+                
+};
+#endif
\ No newline at end of file