text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2020 microDev
   *
   * 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 "peripherals/pcnt.h"
  
  #define PCNT_UNIT_ACTIVE    1
  #define PCNT_UNIT_INACTIVE  0
  
  static uint8_t pcnt_unit_state[4];
  
  void peripherals_pcnt_reset(void) {
      for (uint8_t i = 0; i <= 3; i++) {
          pcnt_unit_state[i] = PCNT_UNIT_INACTIVE;
      }
  }
  
  int peripherals_pcnt_get_unit(pcnt_config_t pcnt_config) {
      // Look for available pcnt unit
      for (uint8_t i = 0; i <= 3; i++) {
          if (pcnt_unit_state[i] == PCNT_UNIT_INACTIVE) {
              pcnt_config.unit = (pcnt_unit_t)i;
              pcnt_unit_state[i] = PCNT_UNIT_ACTIVE;
              break;
          } else if (i == 3) {
              return -1;
          }
      }
  
      return pcnt_config.unit;
  }
  
  int peripherals_pcnt_init(pcnt_config_t pcnt_config) {
      // Look for available pcnt unit
  
      const int8_t unit = peripherals_pcnt_get_unit(pcnt_config);
      if (unit == -1) {
          return -1;
      }
  
      // Initialize PCNT unit
      pcnt_unit_config(&pcnt_config);
  
      // Initialize PCNT's counter
      pcnt_counter_pause(pcnt_config.unit);
      pcnt_counter_clear(pcnt_config.unit);
  
      // Everything is set up, now go to counting
      pcnt_counter_resume(pcnt_config.unit);
  
      return pcnt_config.unit;
  }
  
  void peripherals_pcnt_deinit(pcnt_unit_t *unit) {
      pcnt_unit_state[*unit] = PCNT_UNIT_INACTIVE;
      *unit = PCNT_UNIT_MAX;
  }
  