Debouncing library (not mine)
Dependents: ElecPneuShifter_4 tarea1 tarea_miercoles Rampa ... more
DebouncedIn.cpp@0:8992c13bbb9b, 2010-11-28 (annotated)
- Committer:
- WarwickRacing
- Date:
- Sun Nov 28 14:19:52 2010 +0000
- Revision:
- 0:8992c13bbb9b
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
WarwickRacing | 0:8992c13bbb9b | 1 | #include "DebouncedIn.h" |
WarwickRacing | 0:8992c13bbb9b | 2 | #include "mbed.h" |
WarwickRacing | 0:8992c13bbb9b | 3 | |
WarwickRacing | 0:8992c13bbb9b | 4 | /* |
WarwickRacing | 0:8992c13bbb9b | 5 | * Constructor |
WarwickRacing | 0:8992c13bbb9b | 6 | */ |
WarwickRacing | 0:8992c13bbb9b | 7 | DebouncedIn::DebouncedIn(PinName in) |
WarwickRacing | 0:8992c13bbb9b | 8 | : _in(in) { |
WarwickRacing | 0:8992c13bbb9b | 9 | |
WarwickRacing | 0:8992c13bbb9b | 10 | // reset all the flags and counters |
WarwickRacing | 0:8992c13bbb9b | 11 | _samples = 0; |
WarwickRacing | 0:8992c13bbb9b | 12 | _output = 0; |
WarwickRacing | 0:8992c13bbb9b | 13 | _output_last = 0; |
WarwickRacing | 0:8992c13bbb9b | 14 | _rising_flag = 0; |
WarwickRacing | 0:8992c13bbb9b | 15 | _falling_flag = 0; |
WarwickRacing | 0:8992c13bbb9b | 16 | _state_counter = 0; |
WarwickRacing | 0:8992c13bbb9b | 17 | |
WarwickRacing | 0:8992c13bbb9b | 18 | // Attach ticker |
WarwickRacing | 0:8992c13bbb9b | 19 | _ticker.attach(this, &DebouncedIn::_sample, 0.005); |
WarwickRacing | 0:8992c13bbb9b | 20 | } |
WarwickRacing | 0:8992c13bbb9b | 21 | |
WarwickRacing | 0:8992c13bbb9b | 22 | void DebouncedIn::_sample() { |
WarwickRacing | 0:8992c13bbb9b | 23 | |
WarwickRacing | 0:8992c13bbb9b | 24 | // take a sample |
WarwickRacing | 0:8992c13bbb9b | 25 | _samples = _samples >> 1; // shift left |
WarwickRacing | 0:8992c13bbb9b | 26 | |
WarwickRacing | 0:8992c13bbb9b | 27 | if (_in) { |
WarwickRacing | 0:8992c13bbb9b | 28 | _samples |= 0x80; |
WarwickRacing | 0:8992c13bbb9b | 29 | } |
WarwickRacing | 0:8992c13bbb9b | 30 | |
WarwickRacing | 0:8992c13bbb9b | 31 | // examine the sample window, look for steady state |
WarwickRacing | 0:8992c13bbb9b | 32 | if (_samples == 0x00) { |
WarwickRacing | 0:8992c13bbb9b | 33 | _output = 0; |
WarwickRacing | 0:8992c13bbb9b | 34 | } |
WarwickRacing | 0:8992c13bbb9b | 35 | else if (_samples == 0xFF) { |
WarwickRacing | 0:8992c13bbb9b | 36 | _output = 1; |
WarwickRacing | 0:8992c13bbb9b | 37 | } |
WarwickRacing | 0:8992c13bbb9b | 38 | |
WarwickRacing | 0:8992c13bbb9b | 39 | |
WarwickRacing | 0:8992c13bbb9b | 40 | // Rising edge detection |
WarwickRacing | 0:8992c13bbb9b | 41 | if ((_output == 1) && (_output_last == 0)) { |
WarwickRacing | 0:8992c13bbb9b | 42 | _rising_flag++; |
WarwickRacing | 0:8992c13bbb9b | 43 | _state_counter = 0; |
WarwickRacing | 0:8992c13bbb9b | 44 | } |
WarwickRacing | 0:8992c13bbb9b | 45 | |
WarwickRacing | 0:8992c13bbb9b | 46 | // Falling edge detection |
WarwickRacing | 0:8992c13bbb9b | 47 | else if ((_output == 0) && (_output_last == 1)) { |
WarwickRacing | 0:8992c13bbb9b | 48 | _falling_flag++; |
WarwickRacing | 0:8992c13bbb9b | 49 | _state_counter = 0; |
WarwickRacing | 0:8992c13bbb9b | 50 | } |
WarwickRacing | 0:8992c13bbb9b | 51 | |
WarwickRacing | 0:8992c13bbb9b | 52 | // steady state |
WarwickRacing | 0:8992c13bbb9b | 53 | else { |
WarwickRacing | 0:8992c13bbb9b | 54 | _state_counter++; |
WarwickRacing | 0:8992c13bbb9b | 55 | } |
WarwickRacing | 0:8992c13bbb9b | 56 | |
WarwickRacing | 0:8992c13bbb9b | 57 | // update the output |
WarwickRacing | 0:8992c13bbb9b | 58 | _output_last = _output; |
WarwickRacing | 0:8992c13bbb9b | 59 | |
WarwickRacing | 0:8992c13bbb9b | 60 | } |
WarwickRacing | 0:8992c13bbb9b | 61 | |
WarwickRacing | 0:8992c13bbb9b | 62 | |
WarwickRacing | 0:8992c13bbb9b | 63 | |
WarwickRacing | 0:8992c13bbb9b | 64 | // return number of rising edges |
WarwickRacing | 0:8992c13bbb9b | 65 | int DebouncedIn::rising(void) { |
WarwickRacing | 0:8992c13bbb9b | 66 | int return_value = _rising_flag; |
WarwickRacing | 0:8992c13bbb9b | 67 | _rising_flag = 0; |
WarwickRacing | 0:8992c13bbb9b | 68 | return(return_value); |
WarwickRacing | 0:8992c13bbb9b | 69 | } |
WarwickRacing | 0:8992c13bbb9b | 70 | |
WarwickRacing | 0:8992c13bbb9b | 71 | // return number of falling edges |
WarwickRacing | 0:8992c13bbb9b | 72 | int DebouncedIn::falling(void) { |
WarwickRacing | 0:8992c13bbb9b | 73 | int return_value = _falling_flag; |
WarwickRacing | 0:8992c13bbb9b | 74 | _falling_flag = 0; |
WarwickRacing | 0:8992c13bbb9b | 75 | return(return_value); |
WarwickRacing | 0:8992c13bbb9b | 76 | } |
WarwickRacing | 0:8992c13bbb9b | 77 | |
WarwickRacing | 0:8992c13bbb9b | 78 | // return number of ticsk we've bene steady for |
WarwickRacing | 0:8992c13bbb9b | 79 | int DebouncedIn::steady(void) { |
WarwickRacing | 0:8992c13bbb9b | 80 | return(_state_counter); |
WarwickRacing | 0:8992c13bbb9b | 81 | } |
WarwickRacing | 0:8992c13bbb9b | 82 | |
WarwickRacing | 0:8992c13bbb9b | 83 | // return the debounced status |
WarwickRacing | 0:8992c13bbb9b | 84 | int DebouncedIn::read(void) { |
WarwickRacing | 0:8992c13bbb9b | 85 | return(_output); |
WarwickRacing | 0:8992c13bbb9b | 86 | } |
WarwickRacing | 0:8992c13bbb9b | 87 | |
WarwickRacing | 0:8992c13bbb9b | 88 | // shorthand for read() |
WarwickRacing | 0:8992c13bbb9b | 89 | DebouncedIn::operator int() { |
WarwickRacing | 0:8992c13bbb9b | 90 | return read(); |
WarwickRacing | 0:8992c13bbb9b | 91 | } |