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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  ~PwmOut();
65 
66  /** Set the output duty-cycle, specified as a percentage (float)
67  *
68  * @param value A floating-point value representing the output duty-cycle,
69  * specified as a percentage. The value should lie between
70  * 0.0f (representing on 0%) and 1.0f (representing on 100%).
71  * Values outside this range will be saturated to 0.0f or 1.0f.
72  */
73  void write(float value);
74 
75  /** Return the current output duty-cycle setting, measured as a percentage (float)
76  *
77  * @returns
78  * A floating-point value representing the current duty-cycle being output on the pin,
79  * measured as a percentage. The returned value will lie between
80  * 0.0f (representing on 0%) and 1.0f (representing on 100%).
81  *
82  * @note
83  * This value may not match exactly the value set by a previous write().
84  */
85  float read();
86 
87  /** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
88  *
89  * @param seconds Change the period of a PWM signal in seconds (float) without modifying the duty cycle
90  * @note
91  * The resolution is currently in microseconds; periods smaller than this
92  * will be set to zero.
93  */
94  void period(float seconds);
95 
96  /** Set the PWM period, specified in milliseconds (int), keeping the duty cycle the same.
97  * @param ms Change the period of a PWM signal in milliseconds without modifying the duty cycle
98  */
99  void period_ms(int ms);
100 
101  /** Set the PWM period, specified in microseconds (int), keeping the duty cycle the same.
102  * @param us Change the period of a PWM signal in microseconds without modifying the duty cycle
103  */
104  void period_us(int us);
105 
106  /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
107  * @param seconds Change the pulse width of a PWM signal specified in seconds (float)
108  */
109  void pulsewidth(float seconds);
110 
111  /** Set the PWM pulsewidth, specified in milliseconds (int), keeping the period the same.
112  * @param ms Change the pulse width of a PWM signal specified in milliseconds
113  */
114  void pulsewidth_ms(int ms);
115 
116  /** Set the PWM pulsewidth, specified in microseconds (int), keeping the period the same.
117  * @param us Change the pulse width of a PWM signal specified in microseconds
118  */
119  void pulsewidth_us(int us);
120 
121  /** A operator shorthand for write()
122  * \sa PwmOut::write()
123  */
124  PwmOut &operator= (float value)
125  {
126  // Underlying call is thread safe
127  write(value);
128  return *this;
129  }
130 
131  /** A operator shorthand for write()
132  * \sa PwmOut::write()
133  */
134  PwmOut &operator= (PwmOut &rhs)
135  {
136  // Underlying call is thread safe
137  write(rhs.read());
138  return *this;
139  }
140 
141  /** An operator shorthand for read()
142  * \sa PwmOut::read()
143  */
144  operator float()
145  {
146  // Underlying call is thread safe
147  return read();
148  }
149 
150 #if !(DOXYGEN_ONLY)
151 protected:
152  /** Lock deep sleep only if it is not yet locked */
153  void lock_deep_sleep();
154 
155  /** Unlock deep sleep in case it is locked */
156  void unlock_deep_sleep();
157 
158  pwmout_t _pwm;
159  bool _deep_sleep_locked;
160 #endif
161 };
162 
163 /** @}*/
164 
165 } // namespace mbed
166 
167 #endif
168 
169 #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::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::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.
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:124
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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