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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 #include "hal/gpio_api.h"
22 
23 namespace mbed {
24 /**
25  * \defgroup drivers_DigitalOut DigitalOut class
26  * \ingroup drivers-public-api-gpio
27  * @{
28  */
29 
30 /** A digital output, used for setting the state of a pin
31  *
32  * @note Synchronization level: Interrupt safe
33  *
34  * Example:
35  * @code
36  * // Toggle a LED
37  * #include "mbed.h"
38  *
39  * DigitalOut led(LED1);
40  *
41  * int main() {
42  * while(1) {
43  * led = !led;
44  * wait(0.2);
45  * }
46  * }
47  * @endcode
48  */
49 class DigitalOut {
50 
51 public:
52  /** Create a DigitalOut connected to the specified pin
53  *
54  * @param pin DigitalOut pin to connect to
55  */
56  DigitalOut(PinName pin) : gpio()
57  {
58  // No lock needed in the constructor
59  gpio_init_out(&gpio, pin);
60  }
61 
62  /** Create a DigitalOut connected to the specified pin
63  *
64  * @param pin DigitalOut pin to connect to
65  * @param value the initial pin value
66  */
67  DigitalOut(PinName pin, int value) : gpio()
68  {
69  // No lock needed in the constructor
70  gpio_init_out_ex(&gpio, pin, value);
71  }
72 
73  /** Set the output, specified as 0 or 1 (int)
74  *
75  * @param value An integer specifying the pin output value,
76  * 0 for logical 0, 1 (or any other non-zero value) for logical 1
77  */
78  void write(int value)
79  {
80  // Thread safe / atomic HAL call
81  gpio_write(&gpio, value);
82  }
83 
84  /** Return the output setting, represented as 0 or 1 (int)
85  *
86  * @returns
87  * an integer representing the output setting of the pin,
88  * 0 for logical 0, 1 for logical 1
89  */
90  int read()
91  {
92  // Thread safe / atomic HAL call
93  return gpio_read(&gpio);
94  }
95 
96  /** Return the output setting, represented as 0 or 1 (int)
97  *
98  * @returns
99  * Non zero value if pin is connected to uc GPIO
100  * 0 if gpio object was initialized with NC
101  */
102  int is_connected()
103  {
104  // Thread safe / atomic HAL call
105  return gpio_is_connected(&gpio);
106  }
107 
108  /** A shorthand for write()
109  * \sa DigitalOut::write()
110  * @code
111  * DigitalIn button(BUTTON1);
112  * DigitalOut led(LED1);
113  * led = button; // Equivalent to led.write(button.read())
114  * @endcode
115  */
116  DigitalOut &operator= (int value)
117  {
118  // Underlying write is thread safe
119  write(value);
120  return *this;
121  }
122 
123  /** A shorthand for write() using the assignment operator which copies the
124  * state from the DigitalOut argument.
125  * \sa DigitalOut::write()
126  */
127  DigitalOut &operator= (DigitalOut &rhs);
128 
129  /** A shorthand for read()
130  * \sa DigitalOut::read()
131  * @code
132  * DigitalIn button(BUTTON1);
133  * DigitalOut led(LED1);
134  * led = button; // Equivalent to led.write(button.read())
135  * @endcode
136  */
137  operator int()
138  {
139  // Underlying call is thread safe
140  return read();
141  }
142 
143 protected:
144 #if !defined(DOXYGEN_ONLY)
145  gpio_t gpio;
146 #endif //!defined(DOXYGEN_ONLY)
147 };
148 
149 /** @}*/
150 
151 } // namespace mbed
152 
153 #endif
mbed::DigitalOut::operator=
DigitalOut & operator=(int value)
A shorthand for write()
Definition: DigitalOut.h:116
mbed::DigitalOut::DigitalOut
DigitalOut(PinName pin)
Create a DigitalOut connected to the specified pin.
Definition: DigitalOut.h:56
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:102
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:90
mbed::DigitalOut::DigitalOut
DigitalOut(PinName pin, int value)
Create a DigitalOut connected to the specified pin.
Definition: DigitalOut.h:67
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:49
mbed::DigitalOut::write
void write(int value)
Set the output, specified as 0 or 1 (int)
Definition: DigitalOut.h:78
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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