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AnalogOut.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_ANALOGOUT_H
18 #define MBED_ANALOGOUT_H
19 
20 #include "platform/platform.h"
21 
22 #if DEVICE_ANALOGOUT || defined(DOXYGEN_ONLY)
23 
24 #include "hal/analogout_api.h"
25 #include "platform/PlatformMutex.h"
26 
27 namespace mbed {
28 /**
29  * \defgroup drivers_AnalogOut AnalogOut class
30  * \ingroup drivers-public-api-gpio
31  * @{
32  */
33 
34 /** An analog output, used for setting the voltage on a pin
35  *
36  * @note Synchronization level: Thread safe
37  *
38  * Example:
39  * @code
40  * // Make a sawtooth output
41  *
42  * #include "mbed.h"
43  *
44  * AnalogOut tri(p18);
45  * int main() {
46  * while(1) {
47  * tri = tri + 0.01;
48  * wait_us(1);
49  * if(tri == 1) {
50  * tri = 0;
51  * }
52  * }
53  * }
54  * @endcode
55  */
56 class AnalogOut {
57 
58 public:
59 
60  /** Create an AnalogOut connected to the specified pin
61  *
62  * @param pin AnalogOut pin to connect to
63  */
64  AnalogOut(PinName pin)
65  {
66  analogout_init(&_dac, pin);
67  }
68 
69  /** Create an AnalogOut connected to the specified pin
70  *
71  * @param pinmap reference to structure which holds static pinmap.
72  */
73  AnalogOut(const PinMap &&) = delete; // prevent passing of temporary objects
74  AnalogOut(const PinMap &pinmap)
75  {
76  analogout_init_direct(&_dac, &pinmap);
77  }
78 
79  /** Set the output voltage, specified as a percentage (float)
80  *
81  * @param value A floating-point value representing the output voltage,
82  * specified as a percentage. The value should lie between
83  * 0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
84  * Values outside this range will be saturated to 0.0f or 1.0f.
85  */
86  void write(float value);
87 
88  /** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
89  *
90  * @param value 16-bit unsigned short representing the output voltage,
91  * normalized to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
92  */
93  void write_u16(unsigned short value);
94 
95  /** Return the current output voltage setting, measured as a percentage (float)
96  *
97  * @returns
98  * A floating-point value representing the current voltage being output on the pin,
99  * measured as a percentage. The returned value will lie between
100  * 0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
101  *
102  * @note
103  * This value may not match exactly the value set by a previous write().
104  */
105  float read();
106 
107  /** An operator shorthand for write()
108  * \sa AnalogOut::write()
109  */
110  AnalogOut &operator= (float percent)
111  {
112  // Underlying write call is thread safe
113  write(percent);
114  return *this;
115  }
116 
117  /** An operator shorthand for write()
118  * \sa AnalogOut::write()
119  */
120  AnalogOut &operator= (AnalogOut &rhs)
121  {
122  // Underlying write call is thread safe
123  write(rhs.read());
124  return *this;
125  }
126 
127  /** An operator shorthand for read()
128  * \sa AnalogOut::read()
129  */
130  operator float()
131  {
132  // Underlying read call is thread safe
133  return read();
134  }
135 
136  virtual ~AnalogOut()
137  {
138  /** Deinitialize pin configuration.
139  */
140  analogout_free(&_dac);
141  }
142 
143 protected:
144 #if !defined(DOXYGEN_ONLY)
145  virtual void lock()
146  {
147  _mutex.lock();
148  }
149 
150  virtual void unlock()
151  {
152  _mutex.unlock();
153  }
154 
155  dac_t _dac;
156  PlatformMutex _mutex;
157 #endif //!defined(DOXYGEN_ONLY)
158 };
159 
160 /** @}*/
161 
162 } // namespace mbed
163 
164 #endif
165 
166 #endif
mbed::AnalogOut::operator=
AnalogOut & operator=(float percent)
An operator shorthand for write()
Definition: AnalogOut.h:110
mbed::AnalogOut::AnalogOut
AnalogOut(PinName pin)
Create an AnalogOut connected to the specified pin.
Definition: AnalogOut.h:64
analogout_free
void analogout_free(dac_t *obj)
Release the analogout object.
dac_t
struct dac_s dac_t
Analogout hal structure.
Definition: analogout_api.h:34
mbed::AnalogOut
An analog output, used for setting the voltage on a pin.
Definition: AnalogOut.h:56
mbed::AnalogOut::read
float read()
Return the current output voltage setting, measured as a percentage (float)
mbed::AnalogOut::write
void write(float value)
Set the output voltage, specified as a percentage (float)
PlatformMutex
The PlatformMutex class is used to synchronize the execution of threads.
Definition: PlatformMutex.h:47
analogout_init
void analogout_init(dac_t *obj, PinName pin)
Initialize the analogout peripheral.
PinMap
Definition: pinmap.h:31
mbed::AnalogOut::~AnalogOut
virtual ~AnalogOut()
Definition: AnalogOut.h:136
mbed::AnalogOut::write_u16
void write_u16(unsigned short value)
Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF].
analogout_init_direct
void analogout_init_direct(dac_t *obj, const PinMap *pinmap)
Initialize the analogout peripheral.
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