Andy A / SlowPWM

Very simple class to give slow speed PWM using timers and digital out.

Example use...

#include "SlowPWM.h"
SlowPWM MyTimer1(LED1);
SlowPWM MyTimer2(LED2);
SlowPWM MyTimer3(LED3);

main()
{
    MyTimer1.setPeriod(4);
    MyTimer1.setHighTime(2);
    MyTimer1.start();
    MyTimer2.setPeriod(2);
    MyTimer2.setHighTime(1.5);
    MyTimer2.start();
    MyTimer3.setPeriod(3.8);
    MyTimer3.setHighTime(1.5);
    MyTimer3.start();
    while(true) {
        wait(1);
    }
}

Diff: SlowPWM.cpp

Revision:
3:3f7eb3ad23d4
Parent:
2:c90e2d2f52aa
--- a/SlowPWM.cpp	Fri Jun 21 09:33:26 2019 +0000
+++ b/SlowPWM.cpp	Fri Jun 21 09:45:08 2019 +0000
@@ -1,18 +1,18 @@
 #include "SlowPWM.h"
- 
+
 SlowPWM::SlowPWM(const PinName pin ):DigitalOut(pin)
 {
     _repeatTime=1;
     _timeOn=0.5f;
 }
- 
+
 SlowPWM::SlowPWM( const PinName pin, const float period, const float highTime ):DigitalOut(pin)
 {
     setPeriod(period);
     setHighTime(highTime);
     start();
 }
- 
+
 void SlowPWM::setPeriod(const float period)
 {
     _repeatTime = period;
@@ -20,46 +20,54 @@
         _repeatTime = 1;
     setHighTime(_timeOn);  // perform sanity check on high time
 }
- 
+
 void SlowPWM::setHighTime(const float highTime)
 {
-    _timeOn = highTime;
-    if (_timeOn >= _repeatTime)  // check it's not more than the cycle time.
-        _timeOn = _repeatTime/2; // set to 50% if invalid 
+    if (highTime == 0) {
+        stop();
+        write(0);
+    } else if (highTime >= _repeatTime) {
+        stop();
+        write(1);
+    } else {
+        _timeOn = highTime;
+        start();
+    }
 }
- 
-void SlowPWM::setDutyCycle(const float cycle) {
-        if (cycle == 1) {
-          stop();
-          write(1);
-          } else if (cycle == 0) {
-              stop();
-              write(0);
-        } else if ((cycle >0) && (cycle <1)) {
-        _timeOn = _repeatTime*cycle; 
+
+void SlowPWM::setDutyCycle(const float cycle)
+{
+    if (cycle == 1) {
+        stop();
+        write(1);
+    } else if (cycle == 0) {
+        stop();
+        write(0);
+    } else if ((cycle >0) && (cycle <1)) {
+        _timeOn = _repeatTime*cycle;
         start();
-        } else
-        _timeOn = _repeatTime/2; // set to 50% if invalid 
+    } else
+        _timeOn = _repeatTime/2; // set to 50% if invalid
 }
- 
+
 void SlowPWM::stop()
 {
     offTimer.detach();
     cycleTimer.detach();
 }
- 
+
 // start things.
 void SlowPWM::start()
 {
     cycleTimer.attach(callback(this,&SlowPWM::onCycleStart),_repeatTime);
     onCycleStart();
 }
- 
+
 void SlowPWM::onTurnOff(void)
 {
     write(0);
 }
- 
+
 void SlowPWM::onCycleStart(void)
 {
     offTimer.attach(callback(this,&SlowPWM::onTurnOff),_timeOn);