Mbed OS Reference | PwmOut.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2006-2019 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * 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/platform.h"
 
 #if DEVICE_PWMOUT || defined(DOXYGEN_ONLY)
 #include "hal/pwmout_api.h"
 
 namespace mbed {
 /**
  * \defgroup drivers_PwmOut PwmOut class
  * \ingroup drivers-public-api-gpio
  * @{
  */
 
 /** A pulse-width modulation digital output
  *
  * @note Synchronization level: Interrupt safe
  *
  * Example
  * @code
  * // Gradually change the intensity of the LED.
  * #include "mbed.h"
  *
  * PwmOut led(LED1);
  *
  * int main() {
  *     while(1) {
  *         led = led + 0.01;
  *         ThisThread::sleep_for(200);
  *         if(led == 1.0) {
  *             led = 0;
  *         }
  *     }
  * }
  * @endcode
  */
 class PwmOut {
 
 public:
 
     /** Create a PwmOut connected to the specified pin
      *
      *  @param pin PwmOut pin to connect to
      */
     PwmOut(PinName pin);
 
     /** Create a PwmOut connected to the specified pin
      *
      *  @param pinmap reference to structure which holds static pinmap.
      */
     PwmOut(const PinMap &pinmap);
     PwmOut(const PinMap &&) = delete; // prevent passing of temporary objects
 
     ~PwmOut();
 
     /** Set the output 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);
 
     /** 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();
 
     /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
      *
      *  @param seconds Change the period of a PWM signal in seconds (float) without modifying the duty cycle
      *  @note
      *   The resolution is currently in microseconds; periods smaller than this
      *   will be set to zero.
      */
     void period(float seconds);
 
     /** Set the PWM period, specified in milliseconds (int), keeping the duty cycle the same.
      *  @param ms Change the period of a PWM signal in milliseconds without modifying the duty cycle
      */
     void period_ms(int ms);
 
     /** Set the PWM period, specified in microseconds (int), keeping the duty cycle the same.
      *  @param us Change the period of a PWM signal in microseconds without modifying the duty cycle
      */
     void period_us(int us);
 
     /** Read the PWM period
      *  @returns
      *   The PWM period, specified in microseconds (int)
      */
     int read_period_us();
 
     /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
      *  @param seconds Change the pulse width of a PWM signal specified in seconds (float)
      */
     void pulsewidth(float seconds);
 
     /** Set the PWM pulsewidth, specified in milliseconds (int), keeping the period the same.
      *  @param ms Change the pulse width of a PWM signal specified in milliseconds
      */
     void pulsewidth_ms(int ms);
 
     /** Set the PWM pulsewidth, specified in microseconds (int), keeping the period the same.
      *  @param us Change the pulse width of a PWM signal specified in microseconds
      */
     void pulsewidth_us(int us);
 
     /** Read the PWM pulsewidth
      *  @returns
      *   The PWM pulsewith, specified in microseconds (int)
      */
     int read_pulsewitdth_us();
 
     /** Suspend PWM operation
      *
      * Control the PWM state. This is primarily intended
      * for temporary power-saving; This call can
      * allow pwm to be temporarily disabled to permit power saving without
      * losing device state. The subsequent function call must be PwmOut::resume
      * for PWM to resume; any other calls prior to resuming are undefined behavior.
      */
     void suspend();
 
     /** Resume PWM operation
      *
      * Control the PWM state. This is primarily intended
      * to resume PWM operations after a previous PwmOut::suspend call;
      * This call restores the device state prior to suspension.
      */
     void resume();
 
     /** A operator shorthand for write()
      *  \sa PwmOut::write()
      */
     PwmOut &operator= (float value)
     {
         // Underlying call is thread safe
         write(value);
         return *this;
     }
 
     /** A operator shorthand for write()
      * \sa PwmOut::write()
      */
     PwmOut &operator= (PwmOut &rhs)
     {
         // Underlying call is thread safe
         write(rhs.read());
         return *this;
     }
 
     /** An operator shorthand for read()
      * \sa PwmOut::read()
      */
     operator float()
     {
         // Underlying call is thread safe
         return read();
     }
 
 #if !(DOXYGEN_ONLY)
 protected:
     /** Lock deep sleep only if it is not yet locked */
     void lock_deep_sleep();
 
     /** Unlock deep sleep in case it is locked */
     void unlock_deep_sleep();
 
     /** Initialize this instance */
     void init();
 
     /** Power down this instance */
     void deinit();
 
     pwmout_t _pwm;
     PinName _pin;
     bool _deep_sleep_locked;
     bool _initialized;
     float _duty_cycle;
     int _period_us;
 #endif
 };
 
 /** @}*/
 
 } // namespace mbed
 
 #endif
 
 #endif
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