portapack-mayhem/firmware/application/hw/debounce.cpp
2023-06-25 11:32:37 +02:00

109 lines
4.1 KiB
C++

/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
*
* 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"
// Returns TRUE if button state changed (after debouncing)
bool Debounce::feed(const uint8_t bit) {
history_ = (history_ << 1) | (bit & 1);
// "Repeat" handling - simulated button release
if (repeat_ctr_) {
// Make sure the button is still being held continuously
if ((history_ == 0xFF) && !long_press_enabled_) {
// Simulate button press every REPEAT_SUBSEQUENT_DELAY ticks
if (--repeat_ctr_ == 0) {
state_ = !state_;
repeat_ctr_ = REPEAT_SUBSEQUENT_DELAY / 2;
return true;
}
} else {
// It's a real button release; stop simulating
repeat_ctr_ = 0;
}
}
if (state_ == 0) {
// Previous button state was 0 (released);
// Has button been held for DEBOUNCE_COUNT ticks?
if ((history_ & DEBOUNCE_MASK) == DEBOUNCE_MASK) {
state_ = 1;
held_time_ = 0;
// 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;
return false;
}
return true;
}
} else {
// Previous button state was 1 (pressed);
// Has button been released for DEBOUNCE_COUNT ticks?
if ((history_ & DEBOUNCE_MASK) == 0) {
// Button has been released when long_press_enabled_ and before LONG_PRESS_DELAY was reached;
// allow state() function to finally return a single press indication
// (in long press mode, apps won't see button press until the button is released)
if (pulse_upon_release_) {
// leaving state_==1 for one cycle
pulse_upon_release_ = 0;
} else {
state_ = 0;
}
// Reset long_press_occurred_ flag after button is released
long_press_occurred_ = false;
return true;
}
// Has button been held continuously?
if (history_ == 0xFF) {
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 repease_support and long_press support are mutually exclusive)
if (held_time_ == LONG_PRESS_DELAY) {
long_press_occurred_ = true;
pulse_upon_release_ = 0;
held_time_ = 0;
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 {
// Button not continuously pressed; reset counter
held_time_ = 0;
}
}
return false;
}