/* 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_ANALOGIN_H #define MBED_ANALOGIN_H #include "platform/platform.h" #if DEVICE_ANALOGIN || defined(DOXYGEN_ONLY) #include "hal/analogin_api.h" #include "platform/SingletonPtr.h" #include "rtos/Mutex.h" #include <cmath> namespace mbed { /** \defgroup mbed-os-public Public API */ /** \defgroup drivers-public-api Drivers * \ingroup mbed-os-public */ /** \defgroup drivers-public-api-gpio GPIO * \ingroup drivers-public-api */ /** * \defgroup drivers_AnalogIn AnalogIn class * \ingroup drivers-public-api-gpio * @{ */ /** An analog input, used for reading the voltage on a pin * * @note Synchronization level: Thread safe * * Example: * @code * // Print messages when the AnalogIn is greater than 50% * * #include "mbed.h" * * AnalogIn temperature(p20); * * int main() { * while(1) { * if(temperature > 0.5) { * printf("Too hot! (%f)", temperature.read()); * } * } * } * @endcode */ class AnalogIn { public: /** Create an AnalogIn, connected to the specified pin * * @param pinmap reference to structure which holds static pinmap. * @param vref (optional) Reference voltage of this AnalogIn instance (defaults to target.default-adc-vref). * * @note An input voltage at or above the given vref value will produce a 1.0 result when `read` is called */ AnalogIn(const PinMap &pinmap, float vref = MBED_CONF_TARGET_DEFAULT_ADC_VREF); AnalogIn(const PinMap &&, float vref = MBED_CONF_TARGET_DEFAULT_ADC_VREF) = delete; // prevent passing of temporary objects /** Create an AnalogIn, connected to the specified pin * * @param pin AnalogIn pin to connect to * @param vref (optional) Reference voltage of this AnalogIn instance (defaults to target.default-adc-vref). * * @note An input voltage at or above the given vref value will produce a 1.0 result when `read` is called */ AnalogIn(PinName pin, float vref = MBED_CONF_TARGET_DEFAULT_ADC_VREF); /** Read the input voltage, represented as a float in the range [0.0, 1.0] * * @returns A floating-point value representing the current input voltage, measured as a percentage */ float read(); /** Read the input voltage, represented as an unsigned short in the range [0x0, 0xFFFF] * * @returns * 16-bit unsigned short representing the current input voltage, normalized to a 16-bit value */ unsigned short read_u16(); /** * Read the input voltage in volts. The output depends on the target board's * ADC reference voltage (typically equal to supply voltage). The ADC reference voltage * sets the maximum voltage the ADC can quantify (ie: ADC output == ADC_MAX_VALUE when Vin == Vref) * * The target's default ADC reference voltage is determined by the configuration * option target.default-adc_vref. The reference voltage for a particular input * can be manually specified by either the constructor or `AnalogIn::set_reference_voltage`. * * @returns A floating-point value representing the current input voltage, measured in volts. */ float read_voltage(); /** * Sets this AnalogIn instance's reference voltage. * * The AnalogIn's reference voltage is used to scale the output when calling AnalogIn::read_volts * * @param[in] vref New ADC reference voltage for this AnalogIn instance. */ void set_reference_voltage(float vref); /** * Gets this AnalogIn instance's reference voltage. * * @returns A floating-point value representing this AnalogIn's reference voltage, measured in volts. */ float get_reference_voltage() const; /** An operator shorthand for read() * * The float() operator can be used as a shorthand for read() to simplify common code sequences * * Example: * @code * float x = volume.read(); * float x = volume; * * if(volume.read() > 0.25) { ... } * if(volume > 0.25) { ... } * @endcode */ operator float() { // Underlying call is thread safe return read(); } virtual ~AnalogIn() { lock(); analogin_free(&_adc); unlock(); } protected: #if !defined(DOXYGEN_ONLY) virtual void lock() { _mutex->lock(); } virtual void unlock() { _mutex->unlock(); } analogin_t _adc; static SingletonPtr<rtos::Mutex> _mutex; float _vref; #endif //!defined(DOXYGEN_ONLY) }; /** @}*/ } // namespace mbed #endif #endif