text: /*
   * MIT License
   *
   * Copyright (c) 2021 Joey Castillo
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  //-----------------------------------------------------------------------------
  #include <stdlib.h>
  #include <stdint.h>
  #include <stdbool.h>
  #include <string.h>
  #include <stdio.h>
  #include "saml22.h"
  #include "hal_init.h"
  #include "watch.h"
  #include "tusb.h"
  
  int main(void) {
      // ASF code. Initialize the MCU with configuration options from Atmel Studio.
      init_mcu();
  
      // check if we are plugged into USB power.
      watch_enable_digital_input(VBUS_DET);
      watch_enable_pull_down(VBUS_DET);
      if (watch_get_pin_level(VBUS_DET)) {
          // if so, enable USB functionality.
          _watch_enable_usb();
      }
      watch_disable_digital_input(VBUS_DET);
  
      // initialize the delay driver before any user code is called.
      delay_driver_init();
  
      // User code. Give the app a chance to initialize its data structures and state.
      app_init();
  
      // If the RTC is already enabled, we're either waking from BACKUP mode or a reset.
      // Ideally we should check if the TAMPER or CMP0 (alarm) flags are set.
      if (_watch_rtc_is_enabled()) {
          // User code. Give the application a chance to restore state from backup registers.
          app_wake_from_backup();
  
          // disable the tamper interrupt and clear the tamper bit
          hri_rtcmode0_clear_INTEN_TAMPER_bit(RTC);
          hri_rtcmode0_clear_interrupt_TAMPER_bit(RTC);
      }
  
      // Watch library code. Set initial parameters for the device and enable the RTC.
      _watch_init();
  
      // if date/time register is 0 (power on reset state), default year to 2022.
      watch_date_time date_time = watch_rtc_get_date_time();
      if (date_time.reg == 0) {
          date_time.unit.year = 2;
          watch_rtc_set_date_time(date_time);
      }
  
      // User code. Give the app a chance to enable and set up peripherals.
      app_setup();
  
      while (1) {
          bool usb_enabled = hri_usbdevice_get_CTRLA_ENABLE_bit(USB);
          bool can_sleep = app_loop();
  
          if (can_sleep && !usb_enabled) {
              app_prepare_for_standby();
              sleep(4);
              app_wake_from_standby();
          }
      }
  
      return 0;
  }
  