text: /**
   * Copyright (c) 2015 - 2019, Nordic Semiconductor ASA
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without modification,
   * are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form, except as embedded into a Nordic
   *    Semiconductor ASA integrated circuit in a product or a software update for
   *    such product, must reproduce the above copyright notice, this list of
   *    conditions and the following disclaimer in the documentation and/or other
   *    materials provided with the distribution.
   *
   * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
   *    contributors may be used to endorse or promote products derived from this
   *    software without specific prior written permission.
   *
   * 4. This software, with or without modification, must only be used with a
   *    Nordic Semiconductor ASA integrated circuit.
   *
   * 5. Any software provided in binary form under this license must not be reverse
   *    engineered, decompiled, modified and/or disassembled.
   *
   * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
   * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
   * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   */
  
  #ifndef NRFX_PDM_H__
  #define NRFX_PDM_H__
  
  #include <nrfx.h>
  #include <hal/nrf_pdm.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * @defgroup nrfx_pdm PDM driver
   * @{
   * @ingroup nrf_pdm
   * @brief   Pulse Density Modulation (PDM) peripheral driver.
   */
  
  /** @brief Maximum supported PDM buffer size. */
  #define NRFX_PDM_MAX_BUFFER_SIZE 32767
  
  /** @brief PDM error type. */
  typedef enum
  {
      NRFX_PDM_NO_ERROR = 0,      ///< No error.
      NRFX_PDM_ERROR_OVERFLOW = 1 ///< Overflow error.
  } nrfx_pdm_error_t;
  
  /** @brief PDM event structure. */
  typedef struct
  {
      bool             buffer_requested; ///< Buffer request flag.
      int16_t *        buffer_released;  ///< Pointer to the released buffer. Can be NULL.
      nrfx_pdm_error_t error;            ///< Error type.
  } nrfx_pdm_evt_t;
  
  /** @brief PDM interface driver configuration structure. */
  typedef struct
  {
      nrf_pdm_mode_t mode;               ///< Interface operation mode.
      nrf_pdm_edge_t edge;               ///< Sampling mode.
      uint8_t        pin_clk;            ///< CLK pin.
      uint8_t        pin_din;            ///< DIN pin.
      nrf_pdm_freq_t clock_freq;         ///< Clock frequency.
      nrf_pdm_gain_t gain_l;             ///< Left channel gain.
      nrf_pdm_gain_t gain_r;             ///< Right channel gain.
      uint8_t        interrupt_priority; ///< Interrupt priority.
  } nrfx_pdm_config_t;
  
  /**
   * @brief Macro for setting @ref nrfx_pdm_config_t to default settings
   *        in the single-ended mode.
   *
   * @param _pin_clk  CLK output pin.
   * @param _pin_din  DIN input pin.
   */
  #define NRFX_PDM_DEFAULT_CONFIG(_pin_clk, _pin_din)                   \
  {                                                                     \
      .mode               = (nrf_pdm_mode_t)NRFX_PDM_CONFIG_MODE,       \
      .edge               = (nrf_pdm_edge_t)NRFX_PDM_CONFIG_EDGE,       \
      .pin_clk            = _pin_clk,                                   \
      .pin_din            = _pin_din,                                   \
      .clock_freq         = (nrf_pdm_freq_t)NRFX_PDM_CONFIG_CLOCK_FREQ, \
      .gain_l             = NRF_PDM_GAIN_DEFAULT,                       \
      .gain_r             = NRF_PDM_GAIN_DEFAULT,                       \
      .interrupt_priority = NRFX_PDM_CONFIG_IRQ_PRIORITY                \
  }
  
  /**
   * @brief Handler for the PDM interface ready events.
   *
   * This event handler is called on a buffer request, an error or when a buffer
   * is full and ready to be processed.
   *
   * @param[in] p_evt Pointer to the PDM event structure.
   */
  typedef void (*nrfx_pdm_event_handler_t)(nrfx_pdm_evt_t const * const p_evt);
  
  
  /**
   * @brief Function for initializing the PDM interface.
   *
   * @param[in] p_config      Pointer to the structure with the initial configuration.
   * @param[in] event_handler Event handler provided by the user. Cannot be NULL.
   *
   * @retval NRFX_SUCCESS             Initialization was successful.
   * @retval NRFX_ERROR_INVALID_STATE The driver is already initialized.
   * @retval NRFX_ERROR_INVALID_PARAM Invalid configuration was specified.
   */
  nrfx_err_t nrfx_pdm_init(nrfx_pdm_config_t const * p_config,
                           nrfx_pdm_event_handler_t  event_handler);
  
  /**
   * @brief Function for uninitializing the PDM interface.
   *
   * This function stops PDM sampling, if it is in progress.
   */
  void nrfx_pdm_uninit(void);
  
  /**
   * @brief Function for getting the address of a PDM interface task.
   *
   * @param[in] task Task.
   *
   * @return Task address.
   */
  __STATIC_INLINE uint32_t nrfx_pdm_task_address_get(nrf_pdm_task_t task)
  {
      return nrf_pdm_task_address_get(task);
  }
  
  /**
   * @brief Function for getting the state of the PDM interface.
   *
   * @retval true  The PDM interface is enabled.
   * @retval false The PDM interface is disabled.
   */
  __STATIC_INLINE bool nrfx_pdm_enable_check(void)
  {
      return nrf_pdm_enable_check();
  }
  
  /**
   * @brief Function for starting the PDM sampling.
   *
   * @retval NRFX_SUCCESS    Sampling was started successfully or was already in progress.
   * @retval NRFX_ERROR_BUSY Previous start/stop operation is in progress.
   */
  nrfx_err_t nrfx_pdm_start(void);
  
  /**
   * @brief Function for stopping the PDM sampling.
   *
   * When this function is called, the PDM interface is stopped after finishing
   * the current frame.
   * The event handler function might be called once more after calling this function.
   *
   * @retval NRFX_SUCCESS    Sampling was stopped successfully or was already stopped before.
   * @retval NRFX_ERROR_BUSY Previous start/stop operation is in progress.
   */
  nrfx_err_t nrfx_pdm_stop(void);
  
  /**
   * @brief Function for supplying the sample buffer.
   *
   * Call this function after every buffer request event.
   *
   * @param[in] buffer        Pointer to the receive buffer. Cannot be NULL.
   * @param[in] buffer_length Length of the receive buffer in 16-bit words.
   *
   * @retval NRFX_SUCCESS             The buffer was applied successfully.
   * @retval NRFX_ERROR_BUSY          The buffer was already supplied or the peripheral is currently being stopped.
   * @retval NRFX_ERROR_INVALID_STATE The driver was not initialized.
   * @retval NRFX_ERROR_INVALID_PARAM Invalid parameters were provided.
   */
  nrfx_err_t nrfx_pdm_buffer_set(int16_t * buffer, uint16_t buffer_length);
  
  /** @} */
  
  
  void nrfx_pdm_irq_handler(void);
  
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif // NRFX_PDM_H__
  