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DigitalOut.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_DIGITALOUT_H
18 #define MBED_DIGITALOUT_H
19 
20 #include "platform/platform.h"
21 
22 #include "interfaces/InterfaceDigitalOut.h"
23 #include "hal/gpio_api.h"
24 
25 namespace mbed {
26 /**
27  * \defgroup drivers_DigitalOut DigitalOut class
28  * \ingroup drivers-public-api-gpio
29  * @{
30  */
31 
32 /** A digital output, used for setting the state of a pin
33  *
34  * @note Synchronization level: Interrupt safe
35  *
36  * Example:
37  * @code
38  * // Toggle a LED
39  * #include "mbed.h"
40  *
41  * DigitalOut led(LED1);
42  *
43  * int main() {
44  * while(1) {
45  * led = !led;
46  * ThisThread::sleep_for(200);
47  * }
48  * }
49  * @endcode
50  */
51 class DigitalOut
52 #ifdef FEATURE_EXPERIMENTAL_API
53  final : public interface::DigitalOut
54 #endif
55 {
56 
57 public:
58  /** Create a DigitalOut connected to the specified pin
59  *
60  * @param pin DigitalOut pin to connect to
61  */
62  DigitalOut(PinName pin) : gpio()
63  {
64  // No lock needed in the constructor
65  gpio_init_out(&gpio, pin);
66  }
67 
68  /** Create a DigitalOut connected to the specified pin
69  *
70  * @param pin DigitalOut pin to connect to
71  * @param value the initial pin value
72  */
73  DigitalOut(PinName pin, int value) : gpio()
74  {
75  // No lock needed in the constructor
76  gpio_init_out_ex(&gpio, pin, value);
77  }
78 
79  /** Set the output, specified as 0 or 1 (int)
80  *
81  * @param value An integer specifying the pin output value,
82  * 0 for logical 0, 1 (or any other non-zero value) for logical 1
83  */
84  void write(int value)
85  {
86  // Thread safe / atomic HAL call
87  gpio_write(&gpio, value);
88  }
89 
90  /** Return the output setting, represented as 0 or 1 (int)
91  *
92  * @returns
93  * an integer representing the output setting of the pin,
94  * 0 for logical 0, 1 for logical 1
95  */
96  int read()
97  {
98  // Thread safe / atomic HAL call
99  return gpio_read(&gpio);
100  }
101 
102  /** Return the output setting, represented as 0 or 1 (int)
103  *
104  * @returns
105  * Non zero value if pin is connected to uc GPIO
106  * 0 if gpio object was initialized with NC
107  */
108  int is_connected()
109  {
110  // Thread safe / atomic HAL call
111  return gpio_is_connected(&gpio);
112  }
113 
114  /** A shorthand for write()
115  * \sa DigitalOut::write()
116  * @code
117  * DigitalIn button(BUTTON1);
118  * DigitalOut led(LED1);
119  * led = button; // Equivalent to led.write(button.read())
120  * @endcode
121  */
122  DigitalOut &operator= (int value)
123  {
124  // Underlying write is thread safe
125  write(value);
126  return *this;
127  }
128 
129  /** A shorthand for write() using the assignment operator which copies the
130  * state from the DigitalOut argument.
131  * \sa DigitalOut::write()
132  */
133  DigitalOut &operator= (DigitalOut &rhs);
134 
135  /** A shorthand for read()
136  * \sa DigitalOut::read()
137  * @code
138  * DigitalIn button(BUTTON1);
139  * DigitalOut led(LED1);
140  * led = button; // Equivalent to led.write(button.read())
141  * @endcode
142  */
143  operator int()
144  {
145  // Underlying call is thread safe
146  return read();
147  }
148 
149 protected:
150 #if !defined(DOXYGEN_ONLY)
151  gpio_t gpio;
152 #endif //!defined(DOXYGEN_ONLY)
153 };
154 
155 /** @}*/
156 
157 } // namespace mbed
158 
159 #endif
mbed::DigitalOut::operator=
DigitalOut & operator=(int value)
A shorthand for write()
Definition: DigitalOut.h:122
mbed::DigitalOut::DigitalOut
DigitalOut(PinName pin)
Create a DigitalOut connected to the specified pin.
Definition: DigitalOut.h:62
gpio_is_connected
int gpio_is_connected(const gpio_t *obj)
Checks if gpio object is connected (pin was not initialized with NC)
mbed::DigitalOut::is_connected
int is_connected()
Return the output setting, represented as 0 or 1 (int)
Definition: DigitalOut.h:108
gpio_write
void gpio_write(gpio_t *obj, int value)
Set the output value.
gpio_read
int gpio_read(gpio_t *obj)
Read the input value.
mbed::DigitalOut::read
int read()
Return the output setting, represented as 0 or 1 (int)
Definition: DigitalOut.h:96
mbed::DigitalOut::DigitalOut
DigitalOut(PinName pin, int value)
Create a DigitalOut connected to the specified pin.
Definition: DigitalOut.h:73
gpio_init_out
void gpio_init_out(gpio_t *gpio, PinName pin)
Init the output pin as an output, with predefined output value 0.
mbed::DigitalOut
A digital output, used for setting the state of a pin.
Definition: DigitalOut.h:51
mbed
Definition: ATHandler.h:46
mbed::DigitalOut::write
void write(int value)
Set the output, specified as 0 or 1 (int)
Definition: DigitalOut.h:84
gpio_init_out_ex
void gpio_init_out_ex(gpio_t *gpio, PinName pin, int value)
Init the pin as an output and set the output value.
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