Jan Kamidra / DebounceIn

Extends DigitalIn to DebounceIn to provide mechanical switch debouncing. Fork of original https://os.mbed.com/users/AjK/code/DebounceIn/ and modification for compatibility under MbedOS6+

DebounceIn.h@3:f58cd7168693, 22 months ago (annotated)

Committer:
JohnnyK
Date:
Thu Jun 09 17:52:39 2022 +0000
Revision:
3:f58cd7168693
Parent:
2:31ae5cfb44a4 
First under MbedOS6+

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AjK 0:38fc7a626a26 1 /*
AjK 0:38fc7a626a26 2 Copyright (c) 2010 Andy Kirkham
JohnnyK 3:f58cd7168693 3 Copyright (c) 2022 Jan Kamidra
AjK 0:38fc7a626a26 4
AjK 0:38fc7a626a26 5 Permission is hereby granted, free of charge, to any person obtaining a copy
AjK 0:38fc7a626a26 6 of this software and associated documentation files (the "Software"), to deal
AjK 0:38fc7a626a26 7 in the Software without restriction, including without limitation the rights
AjK 0:38fc7a626a26 8 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
AjK 0:38fc7a626a26 9 copies of the Software, and to permit persons to whom the Software is
AjK 0:38fc7a626a26 10 furnished to do so, subject to the following conditions:
AjK 0:38fc7a626a26 11
AjK 0:38fc7a626a26 12 The above copyright notice and this permission notice shall be included in
AjK 0:38fc7a626a26 13 all copies or substantial portions of the Software.
AjK 0:38fc7a626a26 14
AjK 0:38fc7a626a26 15 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
AjK 0:38fc7a626a26 16 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
AjK 0:38fc7a626a26 17 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AjK 0:38fc7a626a26 18 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
AjK 0:38fc7a626a26 19 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
AjK 0:38fc7a626a26 20 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
AjK 0:38fc7a626a26 21 THE SOFTWARE.
AjK 0:38fc7a626a26 22 */
AjK 0:38fc7a626a26 23
AjK 0:38fc7a626a26 24 #ifndef DEBOUNCEIN_H
AjK 0:38fc7a626a26 25 #define DEBOUNCEIN_H
AjK 0:38fc7a626a26 26
AjK 0:38fc7a626a26 27 #include "mbed.h"
AjK 0:38fc7a626a26 28
AjK 0:38fc7a626a26 29 /** DebounceIn adds mechanical switch debouncing to DigitialIn.
AjK 0:38fc7a626a26 30 *
AjK 0:38fc7a626a26 31 * Example:
AjK 0:38fc7a626a26 32 * @code
AjK 0:38fc7a626a26 33 * #include "mbed.h"
AjK 0:38fc7a626a26 34 * #include "DebounceIn.h"
AjK 0:38fc7a626a26 35 *
AjK 0:38fc7a626a26 36 * DebounceIn d(p5);
AjK 0:38fc7a626a26 37 * DigitialOut led1(LED1);
AjK 0:38fc7a626a26 38 * DigitialOut led2(LED2);
AjK 0:38fc7a626a26 39 *
AjK 0:38fc7a626a26 40 * int main() {
AjK 0:38fc7a626a26 41 * while(1) {
AjK 0:38fc7a626a26 42 * led1 = d;
AjK 0:38fc7a626a26 43 * led2 = d.read();
AjK 0:38fc7a626a26 44 * }
AjK 0:38fc7a626a26 45 * }
AjK 0:38fc7a626a26 46 * @endcode
AjK 0:38fc7a626a26 47 *
AjK 0:38fc7a626a26 48 * @see set_debounce_us() To change the sampling frequency.
AjK 0:38fc7a626a26 49 * @see set_samples() To alter the number of samples.
AjK 0:38fc7a626a26 50 *
AjK 0:38fc7a626a26 51 * This example shows one input displayed by two outputs. The input
AjK 0:38fc7a626a26 52 * is debounced by the default 10ms.
AjK 0:38fc7a626a26 53 */
AjK 0:38fc7a626a26 54
AjK 0:38fc7a626a26 55 class DebounceIn : public DigitalIn {
AjK 0:38fc7a626a26 56 public:
AjK 0:38fc7a626a26 57
AjK 0:38fc7a626a26 58 /** set_debounce_us
AjK 0:38fc7a626a26 59 *
AjK 0:38fc7a626a26 60 * Sets the debounce sample period time in microseconds, default is 1000 (1ms)
AjK 0:38fc7a626a26 61 *
AjK 0:38fc7a626a26 62 * @param int i The debounce sample period time to set.
AjK 0:38fc7a626a26 63 */
JohnnyK 3:f58cd7168693 64 void set_debounce_us(int i) { _ticker.attach(callback(this, &DebounceIn::_callback), std::chrono::microseconds(i)); }
AjK 0:38fc7a626a26 65
AjK 0:38fc7a626a26 66 /** set_samples
AjK 0:38fc7a626a26 67 *
AjK 0:38fc7a626a26 68 * Defines the number of samples before switching the shadow
AjK 0:38fc7a626a26 69 * definition of the pin.
AjK 0:38fc7a626a26 70 *
AjK 0:38fc7a626a26 71 * @param int i The number of samples.
AjK 0:38fc7a626a26 72 */
AjK 0:38fc7a626a26 73 void set_samples(int i) { _samples = i; }
AjK 0:38fc7a626a26 74
AjK 0:38fc7a626a26 75 /** read
AjK 0:38fc7a626a26 76 *
AjK 0:38fc7a626a26 77 * Read the value of the debounced pin.
AjK 0:38fc7a626a26 78 */
AjK 0:38fc7a626a26 79 int read(void) { return _shadow; }
AjK 0:38fc7a626a26 80
AjK 0:38fc7a626a26 81 #ifdef MBED_OPERATORS
AjK 0:38fc7a626a26 82 /** operator int()
AjK 0:38fc7a626a26 83 *
AjK 0:38fc7a626a26 84 * Read the value of the debounced pin.
AjK 0:38fc7a626a26 85 */
AjK 0:38fc7a626a26 86 operator int() { return read(); }
AjK 0:38fc7a626a26 87 #endif
AjK 0:38fc7a626a26 88
AjK 0:38fc7a626a26 89 /** Constructor
AjK 0:38fc7a626a26 90 *
AjK 0:38fc7a626a26 91 * @param PinName pin The pin to assign as an input.
AjK 0:38fc7a626a26 92 */
Sissors 2:31ae5cfb44a4 93 DebounceIn(PinName pin) : DigitalIn(pin) { _counter = 0; _samples = 10; set_debounce_us(1000); };
AjK 0:38fc7a626a26 94
AjK 0:38fc7a626a26 95 protected:
AjK 0:38fc7a626a26 96 void _callback(void) {
AjK 0:38fc7a626a26 97 if (DigitalIn::read()) {
AjK 0:38fc7a626a26 98 if (_counter < _samples) _counter++;
AjK 0:38fc7a626a26 99 if (_counter == _samples) _shadow = 1;
AjK 0:38fc7a626a26 100 }
AjK 0:38fc7a626a26 101 else {
AjK 0:38fc7a626a26 102 if (_counter > 0) _counter--;
AjK 0:38fc7a626a26 103 if (_counter == 0) _shadow = 0;
AjK 0:38fc7a626a26 104 }
AjK 0:38fc7a626a26 105 }
AjK 0:38fc7a626a26 106
AjK 0:38fc7a626a26 107 Ticker _ticker;
AjK 0:38fc7a626a26 108 int _shadow;
AjK 0:38fc7a626a26 109 int _counter;
AjK 0:38fc7a626a26 110 int _samples;
AjK 0:38fc7a626a26 111 };
AjK 0:38fc7a626a26 112
AjK 0:38fc7a626a26 113 #endif
AjK 0:38fc7a626a26 114