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mbed/PwmOut.h 4.24 KB
f7c9a8e1   jdenecha   Feat : Firt dump
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  /* mbed Microcontroller Library

   * Copyright (c) 2006-2013 ARM Limited

   *

   * Licensed under the Apache License, Version 2.0 (the "License");

   * you may not use this file except in compliance with the License.

   * You may obtain a copy of the License at

   *

   *     http://www.apache.org/licenses/LICENSE-2.0

   *

   * Unless required by applicable law or agreed to in writing, software

   * distributed under the License is distributed on an "AS IS" BASIS,

   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

   * See the License for the specific language governing permissions and

   * limitations under the License.

   */

  #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