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AnalogIn.h
1 /* mbed Microcontroller Library
2  * Copyright (c) 2006-2019 ARM Limited
3  * SPDX-License-Identifier: Apache-2.0
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 #ifndef MBED_ANALOGIN_H
18 #define MBED_ANALOGIN_H
19 
20 #include "platform/platform.h"
21 
22 #if DEVICE_ANALOGIN || defined(DOXYGEN_ONLY)
23 
24 #include "hal/analogin_api.h"
25 #include "platform/SingletonPtr.h"
26 #include "platform/PlatformMutex.h"
27 
28 namespace mbed {
29 /** \defgroup mbed-os-public Public API */
30 
31 /** \defgroup drivers-public-api Drivers
32  * \ingroup mbed-os-public
33  */
34 
35 /** \defgroup drivers-public-api-gpio GPIO
36  * \ingroup drivers-public-api
37  */
38 
39 /**
40  * \defgroup drivers_AnalogIn AnalogIn class
41  * \ingroup drivers-public-api-gpio
42  * @{
43  */
44 
45 /** An analog input, used for reading the voltage on a pin
46  *
47  * @note Synchronization level: Thread safe
48  *
49  * Example:
50  * @code
51  * // Print messages when the AnalogIn is greater than 50%
52  *
53  * #include "mbed.h"
54  *
55  * AnalogIn temperature(p20);
56  *
57  * int main() {
58  * while(1) {
59  * if(temperature > 0.5) {
60  * printf("Too hot! (%f)", temperature.read());
61  * }
62  * }
63  * }
64  * @endcode
65  */
66 class AnalogIn {
67 
68 public:
69 
70  /** Create an AnalogIn, connected to the specified pin
71  *
72  * @param pin AnalogIn pin to connect to
73  */
74  AnalogIn(PinName pin);
75 
76  /** Read the input voltage, represented as a float in the range [0.0, 1.0]
77  *
78  * @returns A floating-point value representing the current input voltage, measured as a percentage
79  */
80  float read();
81 
82  /** Read the input voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
83  *
84  * @returns
85  * 16-bit unsigned short representing the current input voltage, normalized to a 16-bit value
86  */
87  unsigned short read_u16();
88 
89  /** An operator shorthand for read()
90  *
91  * The float() operator can be used as a shorthand for read() to simplify common code sequences
92  *
93  * Example:
94  * @code
95  * float x = volume.read();
96  * float x = volume;
97  *
98  * if(volume.read() > 0.25) { ... }
99  * if(volume > 0.25) { ... }
100  * @endcode
101  */
102  operator float()
103  {
104  // Underlying call is thread safe
105  return read();
106  }
107 
108  virtual ~AnalogIn()
109  {
110  // Do nothing
111  }
112 
113 protected:
114 #if !defined(DOXYGEN_ONLY)
115  virtual void lock()
116  {
117  _mutex->lock();
118  }
119 
120  virtual void unlock()
121  {
122  _mutex->unlock();
123  }
124 
125  analogin_t _adc;
126  static SingletonPtr<PlatformMutex> _mutex;
127 #endif //!defined(DOXYGEN_ONLY)
128 
129 };
130 
131 /** @}*/
132 
133 } // namespace mbed
134 
135 #endif
136 
137 #endif
138 
analogin_t
struct analogin_s analogin_t
Analogin hal structure.
Definition: analogin_api.h:34
mbed::AnalogIn
An analog input, used for reading the voltage on a pin.
Definition: AnalogIn.h:66
mbed::AnalogIn::read
float read()
Read the input voltage, represented as a float in the range [0.0, 1.0].
mbed::AnalogIn::read_u16
unsigned short read_u16()
Read the input voltage, represented as an unsigned short in the range [0x0, 0xFFFF].
mbed::AnalogIn::AnalogIn
AnalogIn(PinName pin)
Create an AnalogIn, connected to the specified pin.
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