text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2019 Lucian Copeland for Adafruit Industries
   *
   * 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 "common-hal/pulseio/PulseOut.h"
  
  #include "shared-bindings/pwmio/PWMOut.h"
  #include "py/runtime.h"
  
  // Requires rmt.c void esp32s2_peripherals_reset_all(void) to reset
  
  void common_hal_pulseio_pulseout_construct(pulseio_pulseout_obj_t *self,
      const mcu_pin_obj_t *pin,
      uint32_t frequency,
      uint16_t duty_cycle) {
  
      rmt_channel_t channel = esp32s2_peripherals_find_and_reserve_rmt();
      if (channel == RMT_CHANNEL_MAX) {
          mp_raise_RuntimeError(translate("All timers in use"));
      }
  
      // Configure Channel
      rmt_config_t config = RMT_DEFAULT_CONFIG_TX(pin->number, channel);
      config.tx_config.carrier_en = true;
      config.tx_config.carrier_duty_percent = (duty_cycle * 100) / (1 << 16);
      config.tx_config.carrier_freq_hz = frequency;
      config.clk_div = 80;
  
      rmt_config(&config);
      rmt_driver_install(channel, 0, 0);
  
      self->channel = channel;
  }
  
  bool common_hal_pulseio_pulseout_deinited(pulseio_pulseout_obj_t *self) {
      return self->channel == RMT_CHANNEL_MAX;
  }
  
  void common_hal_pulseio_pulseout_deinit(pulseio_pulseout_obj_t *self) {
      esp32s2_peripherals_free_rmt(self->channel);
      self->channel = RMT_CHANNEL_MAX;
  
  }
  
  void common_hal_pulseio_pulseout_send(pulseio_pulseout_obj_t *self, uint16_t *pulses, uint16_t length) {
      rmt_item32_t items[length];
  
      // Circuitpython allows 16 bit pulse values, while ESP32 only allows 15 bits
      // Thus, we use entire items for one pulse, rather than switching inside each item
      for (size_t i = 0; i < length; i++) {
          // Setting the RMT duration to 0 has undefined behavior, so avoid that pre-emptively.
          if (pulses[i] == 0) {
              pulses[i] = 1;
          }
          uint32_t level = (i % 2) ? 0 : 1;
          const rmt_item32_t item = {{{ (pulses[i] & 0x8000 ? 0x7FFF : 1), level, (pulses[i] & 0x7FFF), level}}};
          items[i] = item;
      }
  
      rmt_write_items(self->channel, items, length, true);
      while (rmt_wait_tx_done(self->channel, 0) != ESP_OK) {
          RUN_BACKGROUND_TASKS;
      }
  }
  