Christian Hernandez / Mbed 2 deprecated VOLTIMETRO2input

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Dependencies:   mbed

Fork of VOLTIMETRO1 by d.a. santana

DebouncedIn.cpp@4:ebe7948a209e, 2017-12-01 (annotated)

Committer:
Christianh
Date:
Fri Dec 01 14:36:25 2017 +0000
Revision:
4:ebe7948a209e
Parent:
0:4676a90107ca 
2input

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tony63 0:4676a90107ca 1 #include "DebouncedIn.h"
tony63 0:4676a90107ca 2 #include "mbed.h"
tony63 0:4676a90107ca 3
tony63 0:4676a90107ca 4 /*
tony63 0:4676a90107ca 5 * Constructor
tony63 0:4676a90107ca 6 */
tony63 0:4676a90107ca 7 DebouncedIn::DebouncedIn(PinName in)
tony63 0:4676a90107ca 8 : _in(in) {
tony63 0:4676a90107ca 9
tony63 0:4676a90107ca 10 // reset all the flags and counters
tony63 0:4676a90107ca 11 _samples = 0;
tony63 0:4676a90107ca 12 _output = 0;
tony63 0:4676a90107ca 13 _output_last = 0;
tony63 0:4676a90107ca 14 _rising_flag = 0;
tony63 0:4676a90107ca 15 _falling_flag = 0;
tony63 0:4676a90107ca 16 _state_counter = 0;
tony63 0:4676a90107ca 17
tony63 0:4676a90107ca 18 // Attach ticker
tony63 0:4676a90107ca 19 _ticker.attach(this, &DebouncedIn::_sample, 0.005);
tony63 0:4676a90107ca 20 }
tony63 0:4676a90107ca 21
tony63 0:4676a90107ca 22 void DebouncedIn::_sample() {
tony63 0:4676a90107ca 23
tony63 0:4676a90107ca 24 // take a sample
tony63 0:4676a90107ca 25 _samples = _samples >> 1; // shift left
tony63 0:4676a90107ca 26
tony63 0:4676a90107ca 27 if (_in) {
tony63 0:4676a90107ca 28 _samples |= 0x80;
tony63 0:4676a90107ca 29 }
tony63 0:4676a90107ca 30
tony63 0:4676a90107ca 31 // examine the sample window, look for steady state
tony63 0:4676a90107ca 32 if (_samples == 0x00) {
tony63 0:4676a90107ca 33 _output = 0;
tony63 0:4676a90107ca 34 }
tony63 0:4676a90107ca 35 else if (_samples == 0xFF) {
tony63 0:4676a90107ca 36 _output = 1;
tony63 0:4676a90107ca 37 }
tony63 0:4676a90107ca 38
tony63 0:4676a90107ca 39
tony63 0:4676a90107ca 40 // Rising edge detection
tony63 0:4676a90107ca 41 if ((_output == 1) && (_output_last == 0)) {
tony63 0:4676a90107ca 42 _rising_flag++;
tony63 0:4676a90107ca 43 _state_counter = 0;
tony63 0:4676a90107ca 44 }
tony63 0:4676a90107ca 45
tony63 0:4676a90107ca 46 // Falling edge detection
tony63 0:4676a90107ca 47 else if ((_output == 0) && (_output_last == 1)) {
tony63 0:4676a90107ca 48 _falling_flag++;
tony63 0:4676a90107ca 49 _state_counter = 0;
tony63 0:4676a90107ca 50 }
tony63 0:4676a90107ca 51
tony63 0:4676a90107ca 52 // steady state
tony63 0:4676a90107ca 53 else {
tony63 0:4676a90107ca 54 _state_counter++;
tony63 0:4676a90107ca 55 }
tony63 0:4676a90107ca 56
tony63 0:4676a90107ca 57 // update the output
tony63 0:4676a90107ca 58 _output_last = _output;
tony63 0:4676a90107ca 59
tony63 0:4676a90107ca 60 }
tony63 0:4676a90107ca 61
tony63 0:4676a90107ca 62
tony63 0:4676a90107ca 63
tony63 0:4676a90107ca 64 // return number of rising edges
tony63 0:4676a90107ca 65 int DebouncedIn::rising(void) {
tony63 0:4676a90107ca 66 int return_value = _rising_flag;
tony63 0:4676a90107ca 67 _rising_flag = 0;
tony63 0:4676a90107ca 68 return(return_value);
tony63 0:4676a90107ca 69 }
tony63 0:4676a90107ca 70
tony63 0:4676a90107ca 71 // return number of falling edges
tony63 0:4676a90107ca 72 int DebouncedIn::falling(void) {
tony63 0:4676a90107ca 73 int return_value = _falling_flag;
tony63 0:4676a90107ca 74 _falling_flag = 0;
tony63 0:4676a90107ca 75 return(return_value);
tony63 0:4676a90107ca 76 }
tony63 0:4676a90107ca 77
tony63 0:4676a90107ca 78 // return number of ticsk we've bene steady for
tony63 0:4676a90107ca 79 int DebouncedIn::steady(void) {
tony63 0:4676a90107ca 80 return(_state_counter);
tony63 0:4676a90107ca 81 }
tony63 0:4676a90107ca 82
tony63 0:4676a90107ca 83 // return the debounced status
tony63 0:4676a90107ca 84 int DebouncedIn::read(void) {
tony63 0:4676a90107ca 85 return(_output);
tony63 0:4676a90107ca 86 }
tony63 0:4676a90107ca 87
tony63 0:4676a90107ca 88 // shorthand for read()
tony63 0:4676a90107ca 89 DebouncedIn::operator int() {
tony63 0:4676a90107ca 90 return read();
tony63 0:4676a90107ca 91 }
tony63 0:4676a90107ca 92
tony63 0:4676a90107ca 93