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debounce.cpp
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debounce.cpp
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/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2023 Mark Thompson
*
* This file is part of PortaPack.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "debounce.hpp"
#include "utility.hpp"
uint8_t Debounce::state() {
bool v = state_to_report_;
simulated_pulse_ = false;
return v;
}
void Debounce::enable_repeat() {
repeat_enabled_ = true;
}
bool Debounce::get_long_press_enabled() const {
return long_press_enabled_;
}
void Debounce::set_long_press_enabled(bool v) {
long_press_enabled_ = v;
}
bool Debounce::long_press_occurred() {
bool v = long_press_occurred_;
long_press_occurred_ = false;
return v;
}
// Returns TRUE if button state changed (after debouncing)
bool Debounce::feed(const uint8_t bit) {
history_ = (history_ << 1) | (bit & 1);
// Has button been held for DEBOUNCE_COUNT ticks?
if ((history_ & DEBOUNCE_MASK) == DEBOUNCE_MASK) {
//
// Button is currently pressed;
// Was previous button state 0 (released)?
//
if (state_ == 0) {
//
// Button has been pressed (after filtering glitches), transition 0->1
//
state_ = 1;
// If long_press_enabled_, state() function masks the button press until it's released
// or until LONG_PRESS_DELAY is reached
if (long_press_enabled_) {
pulse_upon_release_ = true;
state_to_report_ = 0;
return false;
}
state_to_report_ = 1;
return true;
}
// "Repeat" handling - simulated button release
if (repeat_ctr_ && !long_press_enabled_) {
// Simulate button press every REPEAT_SUBSEQUENT_DELAY ticks
// (by toggling reported state every 1/2 of the delay time)
if (--repeat_ctr_ == 0) {
state_to_report_ = !state_to_report_;
repeat_ctr_ = REPEAT_SUBSEQUENT_DELAY / 2;
return true;
}
}
// Keep track of how long button has been held
held_time_++;
if (pulse_upon_release_) {
// Button is being held down and long_press support is enabled for this key:
// if LONG_PRESS_DELAY is reached then finally report that switch is pressed and set flag
// indicating it was a LONG press
// (note that repeat_support and long_press support are mutually exclusive)
if (held_time_ >= LONG_PRESS_DELAY) {
pulse_upon_release_ = false;
long_press_occurred_ = true;
state_to_report_ = 1;
return true;
}
} else if (repeat_enabled_ && !long_press_enabled_) {
// Repeat support -- 4 directional buttons only (unless long_press is enabled)
if (held_time_ >= REPEAT_INITIAL_DELAY) {
// Delay reached; trigger repeat code on NEXT tick
repeat_ctr_ = 1;
held_time_ = 0;
}
}
} else if ((history_ & DEBOUNCE_MASK) == 0) { // Has button been released for at least DEBOUNCE_COUNT ticks?
//
// Button is released;
// Was previous button state 1 (pressed)?
//
if (state_ == 1) {
//
// Button has been released (after filtering glitches), transition 1->0
//
state_ = 0;
long_press_occurred_ = false;
// If button released when long_press_enabled_ and before LONG_PRESS_DELAY was reached;
// allow state() function to finally return a single press indication (simulated pulse).
// Note: In long press mode, apps won't see button press until the button is released.
if (pulse_upon_release_) {
pulse_upon_release_ = false;
simulated_pulse_ = true;
state_to_report_ = 1;
return true;
}
state_to_report_ = 0;
return true;
}
// Reset reported state after application/event has cleared simulated_pulse_
if (state_to_report_ == 1 && !simulated_pulse_) {
state_to_report_ = 0;
return true;
}
} else {
//
// Button is in transition between states;
// Reset counters until button inputs are stable.
//
held_time_ = 0;
repeat_ctr_ = 0;
}
return false;
}