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);
    }
}

SlowPWM.h@3:3f7eb3ad23d4, 2019-06-21 (annotated)

Committer:
AndyA
Date:
Fri Jun 21 09:45:08 2019 +0000
Revision:
3:3f7eb3ad23d4
Parent:
2:c90e2d2f52aa 
Added auto start stop to setHighTime;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AndyA 1:386d04fe1e37 1 #ifndef __SlowPWM_H__
AndyA 1:386d04fe1e37 2 #define __SlowPWM_H__
AndyA 0:76861123625b 3
AndyA 0:76861123625b 4 #include "mbed.h"
AndyA 2:c90e2d2f52aa 5
AndyA 2:c90e2d2f52aa 6
AndyA 2:c90e2d2f52aa 7 /// A basic class to create very slow PWM signals using Digital IO and timers.
AndyA 2:c90e2d2f52aa 8 /// If setting a period and high time then you must manually call start.
AndyA 2:c90e2d2f52aa 9 /// If setting a duty cycle then it will start automatically, make sure you've set the peiod first if you care about it.
AndyA 1:386d04fe1e37 10 class SlowPWM : public DigitalOut
AndyA 0:76861123625b 11 {
AndyA 0:76861123625b 12 public:
AndyA 0:76861123625b 13
AndyA 0:76861123625b 14 // constructor without setting anything going.
AndyA 1:386d04fe1e37 15 SlowPWM( const PinName pin);
AndyA 0:76861123625b 16
AndyA 0:76861123625b 17 // constructor that also starts things running
AndyA 2:c90e2d2f52aa 18 SlowPWM( const PinName pin, const float period, const float highTime);
AndyA 0:76861123625b 19
AndyA 3:3f7eb3ad23d4 20 /// set the period
AndyA 2:c90e2d2f52aa 21 void setPeriod(const float period);
AndyA 0:76861123625b 22
AndyA 3:3f7eb3ad23d4 23 /// set the on time per cycle. If 0 or the period or longer timers are stopped and output set perminently
AndyA 2:c90e2d2f52aa 24 void setHighTime(const float highTime);
AndyA 0:76861123625b 25
AndyA 3:3f7eb3ad23d4 26 // set the on time per cycle as a fraction of the period.
AndyA 2:c90e2d2f52aa 27 void setDutyCycle(const float cycle);
AndyA 0:76861123625b 28
AndyA 2:c90e2d2f52aa 29 // stop things.
AndyA 0:76861123625b 30 void stop();
AndyA 0:76861123625b 31
AndyA 0:76861123625b 32 // start things
AndyA 0:76861123625b 33 void start();
AndyA 0:76861123625b 34
AndyA 0:76861123625b 35 private:
AndyA 0:76861123625b 36 // internal functions and variables not visible to the outside world
AndyA 0:76861123625b 37
AndyA 0:76861123625b 38 void onTurnOff(void);
AndyA 0:76861123625b 39 void onCycleStart(void);
AndyA 0:76861123625b 40
AndyA 0:76861123625b 41 Ticker cycleTimer;
AndyA 0:76861123625b 42 Timeout offTimer;
AndyA 0:76861123625b 43
AndyA 0:76861123625b 44 float _timeOn;
AndyA 0:76861123625b 45 float _repeatTime;
AndyA 0:76861123625b 46 };
AndyA 0:76861123625b 47 #endif