Ben Faucher / DebouncedIn

Library for debouncing inputs, originally by Andres Mora Bedoya. Updated to include PinMode capability and class documentation.

Fork of DebouncedIn by Andrés Mora Bedoya

DebouncedIn.cpp@4:e88ec98d2b7e, 2014-10-16 (annotated)

Committer:
faucherb94
Date:
Thu Oct 16 17:24:35 2014 +0000
Revision:
4:e88ec98d2b7e
Parent:
3:41d314732786 
Updated documentation

Who changed what in which revision?

UserRevisionLine numberNew contents of line
faucherb94 4:e88ec98d2b7e 1 /*
faucherb94 2:261228f701a1 2 * DebouncedIn class version 1.0
faucherb94 2:261228f701a1 3 * Created by Andres Moya Bedoya, updated by Ben Faucher
faucherb94 2:261228f701a1 4 */
faucherb94 2:261228f701a1 5
cmorab 0:dc1131de43e8 6 #include "DebouncedIn.h"
cmorab 0:dc1131de43e8 7 #include "mbed.h"
faucherb94 3:41d314732786 8
cmorab 0:dc1131de43e8 9 DebouncedIn::DebouncedIn(PinName in)
cmorab 0:dc1131de43e8 10 : _in(in) {
cmorab 0:dc1131de43e8 11
faucherb94 2:261228f701a1 12 // Reset all the flags and counters
cmorab 0:dc1131de43e8 13 _samples = 0;
cmorab 0:dc1131de43e8 14 _output = 0;
cmorab 0:dc1131de43e8 15 _output_last = 0;
cmorab 0:dc1131de43e8 16 _rising_flag = 0;
cmorab 0:dc1131de43e8 17 _falling_flag = 0;
cmorab 0:dc1131de43e8 18 _state_counter = 0;
cmorab 0:dc1131de43e8 19
cmorab 0:dc1131de43e8 20 // Attach ticker
cmorab 0:dc1131de43e8 21 _ticker.attach(this, &DebouncedIn::_sample, 0.005);
cmorab 0:dc1131de43e8 22 }
faucherb94 1:7b8a80c09b8c 23
faucherb94 1:7b8a80c09b8c 24 DebouncedIn::DebouncedIn(PinName in, PinMode mode)
faucherb94 1:7b8a80c09b8c 25 : _in(in, mode) {
faucherb94 1:7b8a80c09b8c 26
faucherb94 2:261228f701a1 27 // Reset all the flags and counters
faucherb94 1:7b8a80c09b8c 28 _samples = 0;
faucherb94 1:7b8a80c09b8c 29 _output = 0;
faucherb94 1:7b8a80c09b8c 30 _output_last = 0;
faucherb94 1:7b8a80c09b8c 31 _rising_flag = 0;
faucherb94 1:7b8a80c09b8c 32 _falling_flag = 0;
faucherb94 1:7b8a80c09b8c 33 _state_counter = 0;
faucherb94 1:7b8a80c09b8c 34
faucherb94 1:7b8a80c09b8c 35 // Attach ticker
faucherb94 1:7b8a80c09b8c 36 _ticker.attach(this, &DebouncedIn::_sample, 0.005);
faucherb94 1:7b8a80c09b8c 37 }
faucherb94 2:261228f701a1 38
faucherb94 2:261228f701a1 39 // Public member functions
faucherb94 2:261228f701a1 40
faucherb94 2:261228f701a1 41 int DebouncedIn::read(void) {
faucherb94 2:261228f701a1 42 return(_output);
faucherb94 2:261228f701a1 43 }
faucherb94 3:41d314732786 44
faucherb94 2:261228f701a1 45 DebouncedIn::operator int() {
faucherb94 2:261228f701a1 46 return read();
faucherb94 2:261228f701a1 47 }
faucherb94 2:261228f701a1 48
faucherb94 2:261228f701a1 49 // return number of rising edges
faucherb94 2:261228f701a1 50 int DebouncedIn::rising(void) {
faucherb94 2:261228f701a1 51 int return_value = _rising_flag;
faucherb94 2:261228f701a1 52 _rising_flag = 0;
faucherb94 2:261228f701a1 53 return(return_value);
faucherb94 2:261228f701a1 54 }
faucherb94 2:261228f701a1 55
faucherb94 2:261228f701a1 56 // return number of falling edges
faucherb94 2:261228f701a1 57 int DebouncedIn::falling(void) {
faucherb94 2:261228f701a1 58 int return_value = _falling_flag;
faucherb94 2:261228f701a1 59 _falling_flag = 0;
faucherb94 2:261228f701a1 60 return(return_value);
faucherb94 2:261228f701a1 61 }
faucherb94 2:261228f701a1 62
faucherb94 2:261228f701a1 63 // return number of ticks we've bene steady for
faucherb94 2:261228f701a1 64 int DebouncedIn::steady(void) {
faucherb94 2:261228f701a1 65 return(_state_counter);
faucherb94 2:261228f701a1 66 }
faucherb94 2:261228f701a1 67
faucherb94 2:261228f701a1 68 // Private member functions
cmorab 0:dc1131de43e8 69 void DebouncedIn::_sample() {
cmorab 0:dc1131de43e8 70
cmorab 0:dc1131de43e8 71 // take a sample
faucherb94 2:261228f701a1 72 _samples = _samples >> 1; // shift right 1 bit
cmorab 0:dc1131de43e8 73
cmorab 0:dc1131de43e8 74 if (_in) {
cmorab 0:dc1131de43e8 75 _samples |= 0x80;
cmorab 0:dc1131de43e8 76 }
cmorab 0:dc1131de43e8 77
cmorab 0:dc1131de43e8 78 // examine the sample window, look for steady state
cmorab 0:dc1131de43e8 79 if (_samples == 0x00) {
cmorab 0:dc1131de43e8 80 _output = 0;
cmorab 0:dc1131de43e8 81 }
cmorab 0:dc1131de43e8 82 else if (_samples == 0xFF) {
cmorab 0:dc1131de43e8 83 _output = 1;
cmorab 0:dc1131de43e8 84 }
cmorab 0:dc1131de43e8 85
cmorab 0:dc1131de43e8 86
cmorab 0:dc1131de43e8 87 // Rising edge detection
cmorab 0:dc1131de43e8 88 if ((_output == 1) && (_output_last == 0)) {
cmorab 0:dc1131de43e8 89 _rising_flag++;
cmorab 0:dc1131de43e8 90 _state_counter = 0;
cmorab 0:dc1131de43e8 91 }
cmorab 0:dc1131de43e8 92
cmorab 0:dc1131de43e8 93 // Falling edge detection
cmorab 0:dc1131de43e8 94 else if ((_output == 0) && (_output_last == 1)) {
cmorab 0:dc1131de43e8 95 _falling_flag++;
cmorab 0:dc1131de43e8 96 _state_counter = 0;
cmorab 0:dc1131de43e8 97 }
cmorab 0:dc1131de43e8 98
cmorab 0:dc1131de43e8 99 // steady state
cmorab 0:dc1131de43e8 100 else {
cmorab 0:dc1131de43e8 101 _state_counter++;
cmorab 0:dc1131de43e8 102 }
cmorab 0:dc1131de43e8 103
cmorab 0:dc1131de43e8 104 // update the output
cmorab 0:dc1131de43e8 105 _output_last = _output;
cmorab 0:dc1131de43e8 106
cmorab 0:dc1131de43e8 107 }