mraa/api/mraa/pwm.hpp

/*
 * Author: Brendan Le Foll <brendan.le.foll@intel.com>
 * Copyright (c) 2014 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#pragma once

#include "pwm.h"
#include "types.hpp"
#include <stdexcept>

namespace mraa
{

/**
 * @brief API to Pulse Width Modulation
 *
 * This file defines the PWM interface for libmraa
 *
 * @snippet Pwm3-cycle.cpp Interesting
 */
class Pwm
{
  public:
    /**
     * instanciates a PWM object on a pin
     *
     * @param pin the pin number used on your board
     * @param owner if you are the owner of the pin the destructor will
     * unexport the pin from sysfs, default behaviour is you are the owner
     * if the pinmapper exported it
     * @param chipid the pwmchip to use, use only in raw mode
     */
    Pwm(int pin, bool owner = true, int chipid = -1)
    {
        if (chipid == -1) {
            m_pwm = mraa_pwm_init(pin);
        } else {
            m_pwm = mraa_pwm_init_raw(chipid, pin);
        }

        if (m_pwm == NULL) {
            throw std::invalid_argument("Error initialising PWM on pin");
        }

        if (!owner) {
            mraa_pwm_owner(m_pwm, 0);
        }
    }

    /**
     * Pwm constructor, takes a pointer to the PWM context and
     * initialises the class
     *
     * @param void * to a PWM context
     */
    Pwm(void* pwm_context)
    {
        m_pwm = (mraa_pwm_context) pwm_context;
        if (m_pwm == NULL) {
            throw std::invalid_argument("Invalid PWM context");
        }
    }
    /**
     * Pwm destructor
     */
    ~Pwm()
    {
        mraa_pwm_close(m_pwm);
    }
    /**
     * Set the output duty-cycle percentage, as a float
     *
     * @param percentage A floating-point value representing percentage of
     * output. The value should lie between 0.0f (representing 0%) and
     * 1.0f Values above or below this range will be set at either 0.0f or
     * 1.0f
     * @return Result of operation
     */
    Result
    write(float percentage)
    {
        return (Result) mraa_pwm_write(m_pwm, percentage);
    }
    /**
     * Read the output duty-cycle percentage, as a float
     *
     * @return A floating-point value representing percentage of
     * output. The value should lie between 0.0f (representing 0%) and
     * 1.0f Values above or below this range will be set at either 0.0f or
     * 1.0f
     */
    float
    read()
    {
        return mraa_pwm_read(m_pwm);
    }
    /**
     * Set the PWM period as seconds represented in a float
     *
     * @param period Period represented as a float in seconds
     * @return Result of operation
     */
    Result
    period(float period)
    {
        return (Result) mraa_pwm_period(m_pwm, period);
    }
    /**
     * Set period, milliseconds
     *
     * @param ms milliseconds for period
     * @return Result of operation
     */
    Result
    period_ms(int ms)
    {
        return (Result) mraa_pwm_period_ms(m_pwm, ms);
    }
    /**
     * Set period, microseconds
     *
     * @param us microseconds as period
     * @return Result of operation
     */
    Result
    period_us(int us)
    {
        return (Result) mraa_pwm_period_us(m_pwm, us);
    }
    /**
     * Set pulsewidth, as represented by seconds in a float
     *
     * @param seconds The duration of a pulse
     * @return Result of operation
     */
    Result
    pulsewidth(float seconds)
    {
        return (Result) mraa_pwm_pulsewidth(m_pwm, seconds);
    }
    /**
     * Set pulsewidth, milliseconds
     *
     * @param ms milliseconds for pulsewidth
     * @return Result of operation
     */
    Result
    pulsewidth_ms(int ms)
    {
        return (Result) mraa_pwm_pulsewidth_ms(m_pwm, ms);
    }
    /**
     * The pulsewidth, microseconds
     *
     * @param us microseconds for pulsewidth
     * @return Result of operation
     */
    Result
    pulsewidth_us(int us)
    {
        return (Result) mraa_pwm_pulsewidth_us(m_pwm, us);
    }
    /**
     * Set the enable status of the PWM pin. None zero will assume on with
     * output being driven and 0 will disable the output
     *
     * @param enable enable status of pin
     * @return Result of operation
     */
    Result
    enable(bool enable)
    {
        return (Result) mraa_pwm_enable(m_pwm, enable);
    }
    /**
     * Get the maximum PWM period in us
     *
     * @return max PWM period in us
     */
    int
    max_period()
    {
        return mraa_pwm_get_max_period(m_pwm);
    }
    /**
     * Get the minimum PWM period in us
     *
     * @return min PWM period in us
     */
    int
    min_period()
    {
        return mraa_pwm_get_min_period(m_pwm);
    }

  private:
    mraa_pwm_context m_pwm;
};
}