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PwmOut.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_PWMOUT_H
18 #define MBED_PWMOUT_H
19 
20 #include "platform/platform.h"
21 
22 #if DEVICE_PWMOUT || defined(DOXYGEN_ONLY)
23 #include "hal/pwmout_api.h"
24 
25 namespace mbed {
26 /**
27  * \defgroup drivers_PwmOut PwmOut class
28  * \ingroup drivers-public-api-gpio
29  * @{
30  */
31 
32 /** A pulse-width modulation digital output
33  *
34  * @note Synchronization level: Interrupt safe
35  *
36  * Example
37  * @code
38  * // Gradually change the intensity of the LED.
39  * #include "mbed.h"
40  *
41  * PwmOut led(LED1);
42  *
43  * int main() {
44  * while(1) {
45  * led = led + 0.01;
46  * wait(0.2);
47  * if(led == 1.0) {
48  * led = 0;
49  * }
50  * }
51  * }
52  * @endcode
53  */
54 class PwmOut {
55 
56 public:
57 
58  /** Create a PwmOut connected to the specified pin
59  *
60  * @param pin PwmOut pin to connect to
61  */
62  PwmOut(PinName pin);
63 
64  /** Create a PwmOut connected to the specified pin
65  *
66  * @param pinmap reference to structure which holds static pinmap.
67  */
68  PwmOut(const PinMap &pinmap);
69  PwmOut(const PinMap &&) = delete; // prevent passing of temporary objects
70 
71  ~PwmOut();
72 
73  /** Set the output duty-cycle, specified as a percentage (float)
74  *
75  * @param value A floating-point value representing the output duty-cycle,
76  * specified as a percentage. The value should lie between
77  * 0.0f (representing on 0%) and 1.0f (representing on 100%).
78  * Values outside this range will be saturated to 0.0f or 1.0f.
79  */
80  void write(float value);
81 
82  /** Return the current output duty-cycle setting, measured as a percentage (float)
83  *
84  * @returns
85  * A floating-point value representing the current duty-cycle being output on the pin,
86  * measured as a percentage. The returned value will lie between
87  * 0.0f (representing on 0%) and 1.0f (representing on 100%).
88  *
89  * @note
90  * This value may not match exactly the value set by a previous write().
91  */
92  float read();
93 
94  /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
95  *
96  * @param seconds Change the period of a PWM signal in seconds (float) without modifying the duty cycle
97  * @note
98  * The resolution is currently in microseconds; periods smaller than this
99  * will be set to zero.
100  */
101  void period(float seconds);
102 
103  /** Set the PWM period, specified in milliseconds (int), keeping the duty cycle the same.
104  * @param ms Change the period of a PWM signal in milliseconds without modifying the duty cycle
105  */
106  void period_ms(int ms);
107 
108  /** Set the PWM period, specified in microseconds (int), keeping the duty cycle the same.
109  * @param us Change the period of a PWM signal in microseconds without modifying the duty cycle
110  */
111  void period_us(int us);
112 
113  /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
114  * @param seconds Change the pulse width of a PWM signal specified in seconds (float)
115  */
116  void pulsewidth(float seconds);
117 
118  /** Set the PWM pulsewidth, specified in milliseconds (int), keeping the period the same.
119  * @param ms Change the pulse width of a PWM signal specified in milliseconds
120  */
121  void pulsewidth_ms(int ms);
122 
123  /** Set the PWM pulsewidth, specified in microseconds (int), keeping the period the same.
124  * @param us Change the pulse width of a PWM signal specified in microseconds
125  */
126  void pulsewidth_us(int us);
127 
128  /** Suspend PWM operation
129  *
130  * Control the PWM state. This is primarily intended
131  * for temporary power-saving; This call can
132  * allow pwm to be temporarily disabled to permit power saving without
133  * losing device state. The subsequent function call must be PwmOut::resume
134  * for PWM to resume; any other calls prior to resuming are undefined behavior.
135  */
136  void suspend();
137 
138  /** Resume PWM operation
139  *
140  * Control the PWM state. This is primarily intended
141  * to resume PWM operations after a previous PwmOut::suspend call;
142  * This call restores the device state prior to suspension.
143  */
144  void resume();
145 
146  /** A operator shorthand for write()
147  * \sa PwmOut::write()
148  */
149  PwmOut &operator= (float value)
150  {
151  // Underlying call is thread safe
152  write(value);
153  return *this;
154  }
155 
156  /** A operator shorthand for write()
157  * \sa PwmOut::write()
158  */
159  PwmOut &operator= (PwmOut &rhs)
160  {
161  // Underlying call is thread safe
162  write(rhs.read());
163  return *this;
164  }
165 
166  /** An operator shorthand for read()
167  * \sa PwmOut::read()
168  */
169  operator float()
170  {
171  // Underlying call is thread safe
172  return read();
173  }
174 
175 #if !(DOXYGEN_ONLY)
176 protected:
177  /** Lock deep sleep only if it is not yet locked */
178  void lock_deep_sleep();
179 
180  /** Unlock deep sleep in case it is locked */
181  void unlock_deep_sleep();
182 
183  /** Initialize this instance */
184  void init();
185 
186  /** Power down this instance */
187  void deinit();
188 
189  pwmout_t _pwm;
190  PinName _pin;
191  bool _deep_sleep_locked;
192  bool _initialized;
193  float _duty_cycle;
194 #endif
195 };
196 
197 /** @}*/
198 
199 } // namespace mbed
200 
201 #endif
202 
203 #endif
mbed::PwmOut::write
void write(float value)
Set the output duty-cycle, specified as a percentage (float)
mbed::PwmOut::PwmOut
PwmOut(PinName pin)
Create a PwmOut connected to the specified pin.
mbed::PwmOut::resume
void resume()
Resume PWM operation.
mbed::PwmOut::pulsewidth_us
void pulsewidth_us(int us)
Set the PWM pulsewidth, specified in microseconds (int), keeping the period the same.
mbed::PwmOut
A pulse-width modulation digital output.
Definition: PwmOut.h:54
mbed::PwmOut::read
float read()
Return the current output duty-cycle setting, measured as a percentage (float)
mbed::PwmOut::period_us
void period_us(int us)
Set the PWM period, specified in microseconds (int), keeping the duty cycle the same.
mbed::PwmOut::suspend
void suspend()
Suspend PWM operation.
mbed::PwmOut::period_ms
void period_ms(int ms)
Set the PWM period, specified in milliseconds (int), keeping the duty cycle the same.
mbed::PwmOut::period
void period(float seconds)
Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
mbed::PwmOut::pulsewidth
void pulsewidth(float seconds)
Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
PinMap
Definition: pinmap.h:31
pwmout_t
struct pwmout_s pwmout_t
Pwmout hal structure.
Definition: pwmout_api.h:34
mbed::PwmOut::operator=
PwmOut & operator=(float value)
A operator shorthand for write()
Definition: PwmOut.h:149
mbed::PwmOut::pulsewidth_ms
void pulsewidth_ms(int ms)
Set the PWM pulsewidth, specified in milliseconds (int), keeping the period the same.
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