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drivers/AnalogOut.h
- Committer:
- AnnaBridge
- Date:
- 2017-06-21
- Revision:
- 167:e84263d55307
- Parent:
- 149:156823d33999
File content as of revision 167:e84263d55307:
/* 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_ANALOGOUT_H #define MBED_ANALOGOUT_H #include "platform/platform.h" #if defined (DEVICE_ANALOGOUT) || defined(DOXYGEN_ONLY) #include "hal/analogout_api.h" #include "platform/PlatformMutex.h" namespace mbed { /** \addtogroup drivers */ /** 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 * @ingroup drivers */ 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) { lock(); analogout_write(&_dac, value); unlock(); } /** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF] * * @param value 16-bit unsigned short representing the output voltage, * normalised to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v) */ void write_u16(unsigned short value) { lock(); analogout_write_u16(&_dac, value); unlock(); } /** 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() { lock(); float ret = analogout_read(&_dac); unlock(); return ret; } /** 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() { // Do nothing } protected: virtual void lock() { _mutex.lock(); } virtual void unlock() { _mutex.unlock(); } dac_t _dac; PlatformMutex _mutex; }; } // namespace mbed #endif #endif