Takuo WATANABE / DebounceIn

A digital input with switch debouncing

Dependents:   DebounceIn_Demo RotaryEncoderWaterFlow

DebounceIn.cpp@0:e43521d55082, 2015-12-20 (annotated)

Committer:
takuo
Date:
Sun Dec 20 12:04:08 2015 +0000
Revision:
0:e43521d55082
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
takuo 0:e43521d55082 1 /* A digital input with switch debouncing
takuo 0:e43521d55082 2 * Copyright 2015, Takuo Watanabe
takuo 0:e43521d55082 3 *
takuo 0:e43521d55082 4 * Licensed under the Apache License, Version 2.0 (the "License");
takuo 0:e43521d55082 5 * you may not use this file except in compliance with the License.
takuo 0:e43521d55082 6 * You may obtain a copy of the License at
takuo 0:e43521d55082 7 *
takuo 0:e43521d55082 8 * http://www.apache.org/licenses/LICENSE-2.0
takuo 0:e43521d55082 9 *
takuo 0:e43521d55082 10 * Unless required by applicable law or agreed to in writing, software
takuo 0:e43521d55082 11 * distributed under the License is distributed on an "AS IS" BASIS,
takuo 0:e43521d55082 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
takuo 0:e43521d55082 13 * See the License for the specific language governing permissions and
takuo 0:e43521d55082 14 * limitations under the License.
takuo 0:e43521d55082 15 */
takuo 0:e43521d55082 16
takuo 0:e43521d55082 17 #include "DebounceIn.h"
takuo 0:e43521d55082 18
takuo 0:e43521d55082 19 DebounceIn::DebounceIn(PinName pin, timestamp_t us) : DigitalIn(pin) {
takuo 0:e43521d55082 20 _prev = _curr = 0;
takuo 0:e43521d55082 21 _rise = _fall = NULL;
takuo 0:e43521d55082 22 set_sample_rate(us);
takuo 0:e43521d55082 23 }
takuo 0:e43521d55082 24
takuo 0:e43521d55082 25 DebounceIn::~DebounceIn() {
takuo 0:e43521d55082 26 _ticker.detach();
takuo 0:e43521d55082 27 }
takuo 0:e43521d55082 28
takuo 0:e43521d55082 29 int DebounceIn::read() {
takuo 0:e43521d55082 30 return _curr;
takuo 0:e43521d55082 31 }
takuo 0:e43521d55082 32
takuo 0:e43521d55082 33 #ifdef MBED_OPERATORS
takuo 0:e43521d55082 34 /** An operator shorthand for read()
takuo 0:e43521d55082 35 */
takuo 0:e43521d55082 36 DebounceIn::operator int() {
takuo 0:e43521d55082 37 return read();
takuo 0:e43521d55082 38 }
takuo 0:e43521d55082 39 #endif
takuo 0:e43521d55082 40
takuo 0:e43521d55082 41 void DebounceIn::set_sample_rate(timestamp_t us) {
takuo 0:e43521d55082 42 _ticker.detach();
takuo 0:e43521d55082 43 _ticker.attach_us(this, &DebounceIn::sample, us);
takuo 0:e43521d55082 44 }
takuo 0:e43521d55082 45
takuo 0:e43521d55082 46 void DebounceIn::rise(void (*fptr)(void)) {
takuo 0:e43521d55082 47 _rise.attach(fptr);
takuo 0:e43521d55082 48 }
takuo 0:e43521d55082 49
takuo 0:e43521d55082 50 void DebounceIn::fall(void (*fptr)(void)) {
takuo 0:e43521d55082 51 _fall.attach(fptr);
takuo 0:e43521d55082 52 }
takuo 0:e43521d55082 53
takuo 0:e43521d55082 54 void DebounceIn::sample() {
takuo 0:e43521d55082 55 int now = DigitalIn::read();
takuo 0:e43521d55082 56 if (now == _prev) {
takuo 0:e43521d55082 57 if (!_curr && now) _rise.call();
takuo 0:e43521d55082 58 if (_curr && !now) _fall.call();
takuo 0:e43521d55082 59 _curr = now;
takuo 0:e43521d55082 60 }
takuo 0:e43521d55082 61 _prev = now;
takuo 0:e43521d55082 62 }