PWM.h

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/*
 * PWM.h  Created on: 29 Apr 2014
 * Copyright (c) 2014 Derek Molloy (www.derekmolloy.ie)
 * Made available for the book "Exploring BeagleBone" 
 * See: www.exploringbeaglebone.com
 * Licensed under the EUPL V.1.1
 *
 * This Software is provided to You under the terms of the European 
 * Union Public License (the "EUPL") version 1.1 as published by the 
 * European Union. Any use of this Software, other than as authorized 
 * under this License is strictly prohibited (to the extent such use 
 * is covered by a right of the copyright holder of this Software).
 * 
 * This Software is provided under the License on an "AS IS" basis and 
 * without warranties of any kind concerning the Software, including 
 * without limitation merchantability, fitness for a particular purpose, 
 * absence of defects or errors, accuracy, and non-infringement of 
 * intellectual property rights other than copyright. This disclaimer 
 * of warranty is an essential part of the License and a condition for 
 * the grant of any rights to this Software.
 * 
 * For more details, see http://www.derekmolloy.ie/
 */

#ifndef PWM_H_
#define PWM_H_
#include<string>
using std::string;

#define PWM_PATH "/sys/devices/ocp.3/"
#define PWM_PERIOD "period"
#define PWM_DUTY "duty"
#define PWM_POLARITY "polarity"
#define PWM_RUN "run"

namespace exploringBB {

class PWM {
public:
        enum POLARITY{ ACTIVE_LOW=0, ACTIVE_HIGH=1 };

private:
        string name, path;
        float analogFrequency;  //defaults to 100,000 Hz
        float analogMax;        //defaults to 3.3V

public:
        PWM(string pinName);

        virtual int setPeriod(unsigned int period_ns);
        virtual unsigned int getPeriod();
        virtual int setFrequency(float frequency_hz);
        virtual float getFrequency();
        virtual int setDutyCycle(unsigned int duration_ns);
        virtual int setDutyCycle(float percentage);
        virtual unsigned int getDutyCycle();
        virtual float getDutyCyclePercent();

        virtual int setPolarity(PWM::POLARITY);
        virtual void invertPolarity();
        virtual PWM::POLARITY getPolarity();

        virtual void setAnalogFrequency(float frequency_hz) { this->analogFrequency = frequency_hz; }
        virtual int calibrateAnalogMax(float analogMax); //must be between 3.2 and 3.4
        virtual int analogWrite(float voltage);

        virtual int run();
        virtual bool isRunning();
        virtual int stop();

        virtual ~PWM();
private:
        float period_nsToFrequency(unsigned int);
        unsigned int frequencyToPeriod_ns(float);
};

} /* namespace exploringBB */

#endif /* PWM_H_ */