Mbed OS Reference | AnalogOut.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_ANALOGOUT_H
 #define MBED_ANALOGOUT_H
 
 #include "platform/platform.h"
 
 #if DEVICE_ANALOGOUT || defined(DOXYGEN_ONLY)
 
 #include "hal/analogout_api.h"
 #include "platform/PlatformMutex.h"
 
 namespace mbed {
 /**
  * \defgroup drivers_AnalogOut AnalogOut class
  * \ingroup drivers-public-api-gpio
  * @{
  */
 
 /** An analog output, used for setting the voltage on a pin
  *
  * @note Synchronization level: Thread safe
  *
  * Example:
  * @code
  * // Make a sawtooth output
  *
  * #include "mbed.h"
  *
  * AnalogOut tri(p18);
  * int main() {
  *     while(1) {
  *         tri = tri + 0.01;
  *         wait_us(1);
  *         if(tri == 1) {
  *             tri = 0;
  *         }
  *     }
  * }
  * @endcode
  */
 class AnalogOut {
 
 public:
 
     /** Create an AnalogOut connected to the specified pin
      *
      * @param pin AnalogOut pin to connect to
      */
     AnalogOut(PinName pin)
     {
         analogout_init(&_dac, pin);
     }
 
     /** Set the output voltage, specified as a percentage (float)
      *
      *  @param value A floating-point value representing the output voltage,
      *    specified as a percentage. The value should lie between
      *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
      *    Values outside this range will be saturated to 0.0f or 1.0f.
      */
     void write(float value);
 
     /** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
      *
      *  @param value 16-bit unsigned short representing the output voltage,
      *            normalized to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
      */
     void write_u16(unsigned short value);
 
     /** Return the current output voltage setting, measured as a percentage (float)
      *
      *  @returns
      *    A floating-point value representing the current voltage being output on the pin,
      *    measured as a percentage. The returned value will lie between
      *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
      *
      *  @note
      *    This value may not match exactly the value set by a previous write().
      */
     float read();
 
     /** An operator shorthand for write()
      * \sa AnalogOut::write()
      */
     AnalogOut &operator= (float percent)
     {
         // Underlying write call is thread safe
         write(percent);
         return *this;
     }
 
     /** An operator shorthand for write()
      * \sa AnalogOut::write()
      */
     AnalogOut &operator= (AnalogOut &rhs)
     {
         // Underlying write call is thread safe
         write(rhs.read());
         return *this;
     }
 
     /** An operator shorthand for read()
      * \sa AnalogOut::read()
      */
     operator float()
     {
         // Underlying read call is thread safe
         return read();
     }
 
     virtual ~AnalogOut()
     {
         /** Deinitialize pin configuration.
          */
         analogout_free(&_dac);
     }
 
 protected:
 #if !defined(DOXYGEN_ONLY)
     virtual void lock()
     {
         _mutex.lock();
     }
 
     virtual void unlock()
     {
         _mutex.unlock();
     }
 
     dac_t _dac;
     PlatformMutex _mutex;
 #endif //!defined(DOXYGEN_ONLY)
 };
 
 /** @}*/
 
 } // namespace mbed
 
 #endif
 
 #endif
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