syouichi imamori / SoftPWM

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

Dependents:   SoftPWM_Example XYZ_Joystick_PWM mbed_pwm mbed_Ahan_robocon ... more 

#include "mbed.h"
#include "math.h"
#include "SoftPWM.h"

SoftPWM led[] = { LED1,LED2,LED3,LED4 };

int main()
{
    for ( int i=0; i<4; i++ ) led[i].period_ms( 1 );
    while (1)   {
        for ( int j=0; j<360; j+=10 ) {
            for ( int k=0; k<4; k++ ) {
                led[k] = cos( (j+k*90)*2.0*3.14/360 ) * 0.5 + 0.5;
                wait(0.01);
            }
        }
    }
}

Diff: SoftPWM.cpp

Revision:
0:7918ce37626c
--- /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();
+}
+;
+