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DigitalOut.h
1 /* mbed Microcontroller Library
2  * Copyright (c) 2006-2013 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 #include "platform/mbed_critical.h"
23 
24 namespace mbed {
25 /** \addtogroup drivers */
26 
27 /** A digital output, used for setting the state of a pin
28  *
29  * @note Synchronization level: Interrupt safe
30  *
31  * Example:
32  * @code
33  * // Toggle a LED
34  * #include "mbed.h"
35  *
36  * DigitalOut led(LED1);
37  *
38  * int main() {
39  * while(1) {
40  * led = !led;
41  * wait(0.2);
42  * }
43  * }
44  * @endcode
45  * @ingroup drivers
46  */
47 class DigitalOut {
48 
49 public:
50  /** Create a DigitalOut connected to the specified pin
51  *
52  * @param pin DigitalOut pin to connect to
53  */
54  DigitalOut(PinName pin) : gpio()
55  {
56  // No lock needed in the constructor
57  gpio_init_out(&gpio, pin);
58  }
59 
60  /** Create a DigitalOut connected to the specified pin
61  *
62  * @param pin DigitalOut pin to connect to
63  * @param value the initial pin value
64  */
65  DigitalOut(PinName pin, int value) : gpio()
66  {
67  // No lock needed in the constructor
68  gpio_init_out_ex(&gpio, pin, value);
69  }
70 
71  /** Set the output, specified as 0 or 1 (int)
72  *
73  * @param value An integer specifying the pin output value,
74  * 0 for logical 0, 1 (or any other non-zero value) for logical 1
75  */
76  void write(int value)
77  {
78  // Thread safe / atomic HAL call
79  gpio_write(&gpio, value);
80  }
81 
82  /** Return the output setting, represented as 0 or 1 (int)
83  *
84  * @returns
85  * an integer representing the output setting of the pin,
86  * 0 for logical 0, 1 for logical 1
87  */
88  int read()
89  {
90  // Thread safe / atomic HAL call
91  return gpio_read(&gpio);
92  }
93 
94  /** Return the output setting, represented as 0 or 1 (int)
95  *
96  * @returns
97  * Non zero value if pin is connected to uc GPIO
98  * 0 if gpio object was initialized with NC
99  */
101  {
102  // Thread safe / atomic HAL call
103  return gpio_is_connected(&gpio);
104  }
105 
106  /** A shorthand for write()
107  * \sa DigitalOut::write()
108  * @code
109  * DigitalIn button(BUTTON1);
110  * DigitalOut led(LED1);
111  * led = button; // Equivalent to led.write(button.read())
112  * @endcode
113  */
114  DigitalOut &operator= (int value)
115  {
116  // Underlying write is thread safe
117  write(value);
118  return *this;
119  }
120 
121  /** A shorthand for write() using the assignment operator which copies the
122  * state from the DigitalOut argument.
123  * \sa DigitalOut::write()
124  */
126  {
128  write(rhs.read());
130  return *this;
131  }
132 
133  /** A shorthand for read()
134  * \sa DigitalOut::read()
135  * @code
136  * DigitalIn button(BUTTON1);
137  * DigitalOut led(LED1);
138  * led = button; // Equivalent to led.write(button.read())
139  * @endcode
140  */
141  operator int()
142  {
143  // Underlying call is thread safe
144  return read();
145  }
146 
147 protected:
148 #if !defined(DOXYGEN_ONLY)
149  gpio_t gpio;
150 #endif //!defined(DOXYGEN_ONLY)
151 };
152 
153 } // namespace mbed
154 
155 #endif
DigitalOut & operator=(int value)
A shorthand for write()
Definition: DigitalOut.h:114
DigitalOut(PinName pin)
Create a DigitalOut connected to the specified pin.
Definition: DigitalOut.h:54
void core_util_critical_section_exit(void)
Mark the end of a critical section.
int is_connected()
Return the output setting, represented as 0 or 1 (int)
Definition: DigitalOut.h:100
void gpio_write(gpio_t *obj, int value)
Set the output value.
int gpio_read(gpio_t *obj)
Read the input value.
void core_util_critical_section_enter(void)
Mark the start of a critical section.
int read()
Return the output setting, represented as 0 or 1 (int)
Definition: DigitalOut.h:88
DigitalOut(PinName pin, int value)
Create a DigitalOut connected to the specified pin.
Definition: DigitalOut.h:65
void gpio_init_out(gpio_t *gpio, PinName pin)
Init the output pin as an output, with predefined output value 0.
A digital output, used for setting the state of a pin.
Definition: DigitalOut.h:47
Definition: AnalogIn.h:28
void write(int value)
Set the output, specified as 0 or 1 (int)
Definition: DigitalOut.h:76
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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