git.scottworley.com Git - tattlekey/blob - client/button.c

   1 /* tattlekey: A one-key UDP keyboard
   2  * Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "button.h"
  19 #include "config.h"
  20
  21 #include "hardware/gpio.h"
  22
  23 #include "pico/stdlib.h"
  24
  25 static callback_t button_callback = NULL;
  26
  27 static void respond_to_gpio_interrupt(uint gpio, uint32_t event_mask) {
  28   if (gpio == config_button_pin && event_mask & GPIO_IRQ_EDGE_FALL &&
  29       button_callback) {
  30     button_callback();
  31   }
  32 }
  33
  34 void begin_listening_for_button_press(callback_t callback) {
  35   button_callback = callback;
  36
  37   gpio_set_pulls(config_button_pin, 1, 0);
  38
  39   /* Allow some time for the pull-up to take effect.
  40    * I'm not sure if this is necessary.
  41    * https://datasheets.raspberrypi.com/pico/raspberry-pi-pico-c-sdk.pdf says
  42    * the internal GPIO pull-up resistors are 50k. */
  43   sleep_ms(100);
  44
  45   gpio_set_irq_enabled_with_callback(config_button_pin, GPIO_IRQ_EDGE_FALL, 1,
  46                                      respond_to_gpio_interrupt);
  47 }