ChrisGallagher
0a30a709f0
New compile time opiton for alternative 'prompt' debounce algorithm. Button state changes are avaliable imideatley, so long as the previous state has been stable for the timeout period. Otherwise the state will be updated when the timeout period allows. - Able to report acurate switch times normally with no delay. - Compatable with exising usage. - Use when prompt switch transition timing is important.
128 lines
3.7 KiB
C++
128 lines
3.7 KiB
C++
// Please read Bounce2.h for information about the liscence and authors
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#if defined(ARDUINO) && ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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#include "Bounce2.h"
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#define DEBOUNCED_STATE 0
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#define UNSTABLE_STATE 1
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#define STATE_CHANGED 3
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Bounce::Bounce()
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: previous_millis(0)
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, interval_millis(10)
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, state(0)
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, pin(0)
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{}
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void Bounce::attach(int pin) {
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this->pin = pin;
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state = 0;
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if (digitalRead(pin)) {
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state = _BV(DEBOUNCED_STATE) | _BV(UNSTABLE_STATE);
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}
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#ifdef BOUNCE_LOCK_OUT
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previous_millis = 0;
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#else
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previous_millis = millis();
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#endif
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}
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void Bounce::attach(int pin, int mode){
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pinMode(pin, mode);
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this->attach(pin);
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}
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void Bounce::interval(uint16_t interval_millis)
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{
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this->interval_millis = interval_millis;
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}
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bool Bounce::update()
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{
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#ifdef BOUNCE_LOCK_OUT
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state &= ~_BV(STATE_CHANGED);
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// Ignore everything if we are locked out
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if (millis() - previous_millis >= interval_millis) {
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bool currentState = digitalRead(pin);
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if ((bool)(state & _BV(DEBOUNCED_STATE)) != currentState) {
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previous_millis = millis();
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state ^= _BV(DEBOUNCED_STATE);
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state |= _BV(STATE_CHANGED);
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}
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}
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return state & _BV(STATE_CHANGED);
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#elif defined BOUNCE_WITH_PROMPT_DETECTION
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// Read the state of the switch port into a temporary variable.
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bool readState = digitalRead(pin);
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// Clear Changed State Flag - will be reset if we confirm a button state change.
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state &= ~_BV(STATE_CHANGED);
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if ( readState != (bool)(state & _BV(DEBOUNCED_STATE))) {
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// We have seen a change from the current button state.
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if ( millis() - previous_millis >= interval_millis ) {
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// We have passed the time threshold, so a new change of state is allowed.
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// set the STATE_CHANGED flag and the new DEBOUNCED_STATE.
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// This will be prompt as long as there has been greater than interval_misllis ms since last change of input.
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// Otherwise debounced state will not change again until bouncing is stable for the timeout period.
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state ^= _BV(DEBOUNCED_STATE);
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state |= _BV(STATE_CHANGED);
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}
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}
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// If the readState is different from previous readState, reset the debounce timer - as input is still unstable
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// and we want to prevent new button state changes until the previous one has remained stable for the timeout.
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if ( readState != (bool)(state & _BV(UNSTABLE_STATE)) ) {
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// Update Unstable Bit to macth readState
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state ^= _BV(UNSTABLE_STATE);
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previous_millis = millis();
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}
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// return just the sate changed bit
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return state & _BV(STATE_CHANGED);
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#else
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// Read the state of the switch in a temporary variable.
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bool currentState = digitalRead(pin);
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state &= ~_BV(STATE_CHANGED);
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// If the reading is different from last reading, reset the debounce counter
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if ( currentState != (bool)(state & _BV(UNSTABLE_STATE)) ) {
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previous_millis = millis();
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state ^= _BV(UNSTABLE_STATE);
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} else
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if ( millis() - previous_millis >= interval_millis ) {
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// We have passed the threshold time, so the input is now stable
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// If it is different from last state, set the STATE_CHANGED flag
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if ((bool)(state & _BV(DEBOUNCED_STATE)) != currentState) {
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previous_millis = millis();
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state ^= _BV(DEBOUNCED_STATE);
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state |= _BV(STATE_CHANGED);
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}
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}
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return state & _BV(STATE_CHANGED);
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#endif
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}
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bool Bounce::read()
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{
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return state & _BV(DEBOUNCED_STATE);
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}
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bool Bounce::rose()
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{
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return ( state & _BV(DEBOUNCED_STATE) ) && ( state & _BV(STATE_CHANGED));
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}
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bool Bounce::fell()
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{
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return !( state & _BV(DEBOUNCED_STATE) ) && ( state & _BV(STATE_CHANGED));
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}
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