mbed-os/drivers/AnalogIn.h

155 lines
3.8 KiB
C++

/* 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 "platform/PlatformMutex.h"
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.
*/
AnalogIn(const PinMap &pinmap);
AnalogIn(const PinMap &&) = delete; // prevent passing of temporary objects
/** Create an AnalogIn, connected to the specified pin
*
* @param pin AnalogIn pin to connect to
*/
AnalogIn(PinName pin);
/** 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: Vin == Vref when ADC output == ADC_MAX_VALUE)
*
* The target's ADC reference voltage can be configured by overriding "drivers.adc_vref"
*
* @returns A floating-point value representing the current input voltage, measured in volts.
*/
float read_volts();
/** 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()
{
// Do nothing
}
protected:
#if !defined(DOXYGEN_ONLY)
virtual void lock()
{
_mutex->lock();
}
virtual void unlock()
{
_mutex->unlock();
}
analogin_t _adc;
static SingletonPtr<PlatformMutex> _mutex;
#endif //!defined(DOXYGEN_ONLY)
};
/** @}*/
} // namespace mbed
#endif
#endif