127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
//
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// Copyright 2024 Wenting Zhang <zephray@outlook.com>
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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//
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#include <stdio.h>
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#include "pico/stdlib.h"
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#include "button.h"
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#define BTN1 6
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#define BTN2 5
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#define BTNCNT 2
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#define SHORT_PRESS_THRESHOLD 20
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#define LONG_PRESS_THRESHOLD 500
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#define RELEASE_THRESHOLD 20
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void button_init() {
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gpio_init(BTN1);
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gpio_set_dir(BTN1, GPIO_IN);
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gpio_pull_up(BTN1);
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gpio_init(BTN2);
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gpio_set_dir(BTN2, GPIO_IN);
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gpio_pull_up(BTN2);
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}
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// Scan a single key, ID is the key number from 0, gpio is pin number
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// Should be called at ~1ms interval
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// Return value:
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// 0 when nothing pressed
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// 1 when short pressed
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// 2 when long pressed
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static uint32_t button_scan_single(int id, int gpio) {
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static int timecntr[BTNCNT] = {0};
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static enum {
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STATE_IDLE,
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STATE_FIRST_PRESSED,
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STATE_HOLDING,
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STATE_RELEASED
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} state[BTNCNT] = {0};
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uint32_t retval = 0;
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switch (state[id]) {
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case STATE_IDLE:
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if (gpio_get(gpio) == 0) {
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state[id] = STATE_FIRST_PRESSED;
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timecntr[id] = 0;
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}
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break;
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case STATE_FIRST_PRESSED:
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timecntr[id]++;
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if (gpio_get(gpio) == 0) {
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// Still pressing
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if (timecntr[id] >= SHORT_PRESS_THRESHOLD) {
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state[id] = STATE_HOLDING;
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timecntr[id] = 0;
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}
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}
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else {
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// No longer pressed
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state[id] = STATE_IDLE;
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}
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break;
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case STATE_HOLDING:
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timecntr[id]++;
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if (gpio_get(gpio) == 0) {
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// Still holding
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if (timecntr[id] == LONG_PRESS_THRESHOLD) {
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// Exactly when reaching the threshold, return the key press
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// User gets feedback as soon as the threshold is reached
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retval = 2;
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}
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}
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else {
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// No longer holding
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if (timecntr[id] < LONG_PRESS_THRESHOLD) {
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// Is a short press, signal
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retval = 1;
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}
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timecntr[id] = 0;
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state[id] = STATE_RELEASED;
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}
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break;
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case STATE_RELEASED:
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if (gpio_get(gpio) == 0) {
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// Pressed, reset time counter
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timecntr[id] = 0;
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}
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else {
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// Keep counting time
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// Only treat key as released when reaching threshold
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timecntr[id]++;
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if (timecntr[id] >= RELEASE_THRESHOLD) {
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state[id] = STATE_IDLE;
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}
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}
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break;
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}
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return retval;
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}
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uint32_t button_scan() {
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uint32_t btn1 = button_scan_single(0, BTN1);
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uint32_t btn2 = button_scan_single(1, BTN2);
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uint32_t retval = (btn1 & 0x3) | ((btn2 & 0x3) << 2);
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return retval;
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}
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