File content as of revision 0:fd0d7bdfcdc2:

/* mbed Microcontroller Library
 * Copyright (c) 2006-2012 ARM Limited
 *
 * 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.
 */
#ifndef MBED_PWMOUT_H
#define MBED_PWMOUT_H

#include "platform.h"

#if DEVICE_PWMOUT
#include "pwmout_api.h"

namespace mbed {

/** A pulse-width modulation digital output
 *
 * Example
 * @code
 * // Fade a led on.
 * #include "mbed.h"
 *
 * PwmOut led(LED1);
 * 
 * int main() {
 *     while(1) {
 *         led = led + 0.01;
 *         wait(0.2);
 *         if(led == 1.0) {
 *             led = 0;
 *         }
 *     }
 * }
 * @endcode
 *
 * @note
 *  On the LPC1768 and LPC2368, the PWMs all share the same
 *  period - if you change the period for one, you change it for all.
 *  Although routines that change the period maintain the duty cycle
 *  for its PWM, all other PWMs will require their duty cycle to be
 *  refreshed.
 */
class PwmOut {

public:

    /** Create a PwmOut connected to the specified pin
     *
     *  @param pin PwmOut pin to connect to
     */
    PwmOut(PinName pin) {
        pwmout_init(&_pwm, pin);
    }

    /** Set the ouput duty-cycle, specified as a percentage (float)
     *
     *  @param value A floating-point value representing the output duty-cycle, 
     *    specified as a percentage. The value should lie between
     *    0.0f (representing on 0%) and 1.0f (representing on 100%).
     *    Values outside this range will be saturated to 0.0f or 1.0f.
     */
    void write(float value) {
        pwmout_write(&_pwm, value);
    }

    /** Return the current output duty-cycle setting, measured as a percentage (float)
     *
     *  @returns
     *    A floating-point value representing the current duty-cycle being output on the pin, 
     *    measured as a percentage. The returned value will lie between
     *    0.0f (representing on 0%) and 1.0f (representing on 100%).
     *
     *  @note
     *  This value may not match exactly the value set by a previous <write>.
     */
    float read() {
        return pwmout_read(&_pwm);
    }
    
    /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
     *
     *  @note
     *   The resolution is currently in microseconds; periods smaller than this
     *   will be set to zero.
     */
    void period(float seconds) {
        pwmout_period(&_pwm, seconds);
    }

    /** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
     */
    void period_ms(int ms) {
        pwmout_period_ms(&_pwm, ms);
    }

    /** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
     */
    void period_us(int us) {
        pwmout_period_us(&_pwm, us);
    }

    /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
     */
    void pulsewidth(float seconds) {
        pwmout_pulsewidth(&_pwm, seconds);
    }

    /** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
     */
    void pulsewidth_ms(int ms) {
        pwmout_pulsewidth_ms(&_pwm, ms);
    }

    /** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
     */
    void pulsewidth_us(int us) {
        pwmout_pulsewidth_us(&_pwm, us);
    }

#ifdef MBED_OPERATORS
    /** A operator shorthand for write()
     */
    PwmOut& operator= (float value) {
        write(value);
        return *this;
    }
    
    PwmOut& operator= (PwmOut& rhs) {
        write(rhs.read());
        return *this;
    }
    
    /** An operator shorthand for read()
     */
    operator float() {
        return read();
    }
#endif

protected:
    pwmout_t _pwm;
};

} // namespace mbed

#endif

#endif