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DebouncedFallingEdgeCounter.cpp@1:a197f86e143a, 2014-06-10 (annotated)
- Committer:
- sunilaluri6
- Date:
- Tue Jun 10 00:11:28 2014 +0000
- Revision:
- 1:a197f86e143a
- Parent:
- 0:457832d52954
Rev1.0
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
AdamGreen | 0:457832d52954 | 1 | /* Copyright 2012 Adam Green (http://mbed.org/users/AdamGreen/) |
AdamGreen | 0:457832d52954 | 2 | |
AdamGreen | 0:457832d52954 | 3 | Licensed under the Apache License, Version 2.0 (the "License"); |
AdamGreen | 0:457832d52954 | 4 | you may not use this file except in compliance with the License. |
AdamGreen | 0:457832d52954 | 5 | You may obtain a copy of the License at |
AdamGreen | 0:457832d52954 | 6 | |
AdamGreen | 0:457832d52954 | 7 | http://www.apache.org/licenses/LICENSE-2.0 |
AdamGreen | 0:457832d52954 | 8 | |
AdamGreen | 0:457832d52954 | 9 | Unless required by applicable law or agreed to in writing, software |
AdamGreen | 0:457832d52954 | 10 | distributed under the License is distributed on an "AS IS" BASIS, |
AdamGreen | 0:457832d52954 | 11 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
AdamGreen | 0:457832d52954 | 12 | See the License for the specific language governing permissions and |
AdamGreen | 0:457832d52954 | 13 | limitations under the License. |
AdamGreen | 0:457832d52954 | 14 | */ |
AdamGreen | 0:457832d52954 | 15 | /* Implementation for wrapper class of InterruptIn used for counting falling edge |
AdamGreen | 0:457832d52954 | 16 | events with specified hold off time for the purpose of debouncing. |
AdamGreen | 0:457832d52954 | 17 | */ |
AdamGreen | 0:457832d52954 | 18 | #include <mbed.h> |
AdamGreen | 0:457832d52954 | 19 | #include "DebouncedFallingEdgeCounter.h" |
AdamGreen | 0:457832d52954 | 20 | |
AdamGreen | 0:457832d52954 | 21 | |
AdamGreen | 0:457832d52954 | 22 | CDebouncedFallingEdgeCounter::CDebouncedFallingEdgeCounter(PinName InterruptInPin, unsigned int IgnoreTimeForDebounceInMicroSeconds) |
AdamGreen | 0:457832d52954 | 23 | : m_FallingEdgeInterruptIn(InterruptInPin) |
AdamGreen | 0:457832d52954 | 24 | { |
AdamGreen | 0:457832d52954 | 25 | m_Timer.start(); |
AdamGreen | 0:457832d52954 | 26 | m_IgnoreTimeForDebounce = IgnoreTimeForDebounceInMicroSeconds; |
AdamGreen | 0:457832d52954 | 27 | InitLastFallingEdgeTime(); |
AdamGreen | 0:457832d52954 | 28 | |
AdamGreen | 0:457832d52954 | 29 | ZeroCount(); |
AdamGreen | 0:457832d52954 | 30 | |
AdamGreen | 0:457832d52954 | 31 | m_FallingEdgeInterruptIn.mode(PullUp); |
AdamGreen | 0:457832d52954 | 32 | m_FallingEdgeInterruptIn.fall<CDebouncedFallingEdgeCounter>(this, &CDebouncedFallingEdgeCounter::FallingEdgeISR); |
AdamGreen | 0:457832d52954 | 33 | } |
AdamGreen | 0:457832d52954 | 34 | |
AdamGreen | 0:457832d52954 | 35 | |
AdamGreen | 0:457832d52954 | 36 | void CDebouncedFallingEdgeCounter::InitLastFallingEdgeTime() |
AdamGreen | 0:457832d52954 | 37 | { |
AdamGreen | 0:457832d52954 | 38 | InitLastFallingEdgeTime((unsigned int)m_Timer.read_us()); |
AdamGreen | 0:457832d52954 | 39 | } |
AdamGreen | 0:457832d52954 | 40 | |
AdamGreen | 0:457832d52954 | 41 | |
AdamGreen | 0:457832d52954 | 42 | void CDebouncedFallingEdgeCounter::InitLastFallingEdgeTime(unsigned int CurrentTime) |
AdamGreen | 0:457832d52954 | 43 | { |
AdamGreen | 0:457832d52954 | 44 | m_LastFallingEdgeTime = CurrentTime - m_IgnoreTimeForDebounce; |
AdamGreen | 0:457832d52954 | 45 | } |
AdamGreen | 0:457832d52954 | 46 | |
AdamGreen | 0:457832d52954 | 47 | |
AdamGreen | 0:457832d52954 | 48 | void CDebouncedFallingEdgeCounter::FallingEdgeISR() |
AdamGreen | 0:457832d52954 | 49 | { |
AdamGreen | 0:457832d52954 | 50 | // UNDONE: Can I just use whatever timer the m_Timer uses under the covers? |
AdamGreen | 0:457832d52954 | 51 | unsigned int CurrentTime = (unsigned int)m_Timer.read_us(); |
AdamGreen | 0:457832d52954 | 52 | |
AdamGreen | 0:457832d52954 | 53 | if (TimeSinceLastFallingEdge(CurrentTime) >= m_IgnoreTimeForDebounce) |
AdamGreen | 0:457832d52954 | 54 | { |
AdamGreen | 0:457832d52954 | 55 | m_FallingEdgeCount++; |
AdamGreen | 0:457832d52954 | 56 | m_LastFallingEdgeTime = CurrentTime; |
AdamGreen | 0:457832d52954 | 57 | } |
AdamGreen | 0:457832d52954 | 58 | } |
AdamGreen | 0:457832d52954 | 59 | |
AdamGreen | 0:457832d52954 | 60 | |
AdamGreen | 0:457832d52954 | 61 | unsigned int CDebouncedFallingEdgeCounter::TimeSinceLastFallingEdge(unsigned int CurrentTime) |
AdamGreen | 0:457832d52954 | 62 | { |
AdamGreen | 0:457832d52954 | 63 | return CurrentTime - m_LastFallingEdgeTime; |
AdamGreen | 0:457832d52954 | 64 | } |
AdamGreen | 0:457832d52954 | 65 | |
AdamGreen | 0:457832d52954 | 66 | |
AdamGreen | 0:457832d52954 | 67 | unsigned int CDebouncedFallingEdgeCounter::GetCountAndZero() |
AdamGreen | 0:457832d52954 | 68 | { |
AdamGreen | 0:457832d52954 | 69 | unsigned int CurrentCount; |
AdamGreen | 0:457832d52954 | 70 | |
AdamGreen | 0:457832d52954 | 71 | CurrentCount = GetCount(); |
AdamGreen | 0:457832d52954 | 72 | ZeroCount(); |
AdamGreen | 0:457832d52954 | 73 | return CurrentCount; |
AdamGreen | 0:457832d52954 | 74 | } |
AdamGreen | 0:457832d52954 | 75 | |
AdamGreen | 0:457832d52954 | 76 | |
AdamGreen | 0:457832d52954 | 77 | unsigned int CDebouncedFallingEdgeCounter::GetCount() |
AdamGreen | 0:457832d52954 | 78 | { |
AdamGreen | 0:457832d52954 | 79 | RefreshTimers(); |
AdamGreen | 0:457832d52954 | 80 | |
AdamGreen | 0:457832d52954 | 81 | return m_FallingEdgeCount; |
AdamGreen | 0:457832d52954 | 82 | } |
AdamGreen | 0:457832d52954 | 83 | |
AdamGreen | 0:457832d52954 | 84 | |
AdamGreen | 0:457832d52954 | 85 | void CDebouncedFallingEdgeCounter::ZeroCount() |
AdamGreen | 0:457832d52954 | 86 | { |
AdamGreen | 0:457832d52954 | 87 | m_FallingEdgeCount = 0; |
AdamGreen | 0:457832d52954 | 88 | } |
AdamGreen | 0:457832d52954 | 89 | |
AdamGreen | 0:457832d52954 | 90 | |
AdamGreen | 0:457832d52954 | 91 | void CDebouncedFallingEdgeCounter::RefreshTimers() |
AdamGreen | 0:457832d52954 | 92 | { |
AdamGreen | 0:457832d52954 | 93 | unsigned int CurrentTime = (unsigned int)m_Timer.read_us(); |
AdamGreen | 0:457832d52954 | 94 | |
AdamGreen | 0:457832d52954 | 95 | if (TimeSinceLastFallingEdge(CurrentTime) > m_IgnoreTimeForDebounce) |
AdamGreen | 0:457832d52954 | 96 | { |
AdamGreen | 0:457832d52954 | 97 | // Protect from timer overflow. |
AdamGreen | 0:457832d52954 | 98 | InitLastFallingEdgeTime(CurrentTime); |
AdamGreen | 0:457832d52954 | 99 | } |
AdamGreen | 0:457832d52954 | 100 | } |