text: /* 
   * Copyright (c) 2015 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 or object form under this license must not be reverse 
   *      engineered, decompiled, modified and/or disassembled. 
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER 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 NRF_TWI_H__
  #define NRF_TWI_H__
  
  /**
   * @defgroup nrf_twi_hal TWI HAL
   * @{
   * @ingroup nrf_twi
   *
   * @brief Hardware access layer for managing the TWI peripheral.
   */
  
  #include <stdint.h>
  #include <stddef.h>
  #include <stdbool.h>
  
  #include "nrf_peripherals.h"
  #include "nrf.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * @brief TWI tasks.
   */
  typedef enum
  {
      /*lint -save -e30*/
      NRF_TWI_TASK_STARTRX = offsetof(NRF_TWI_Type, TASKS_STARTRX), ///< Start TWI receive sequence.
      NRF_TWI_TASK_STARTTX = offsetof(NRF_TWI_Type, TASKS_STARTTX), ///< Start TWI transmit sequence.
      NRF_TWI_TASK_STOP    = offsetof(NRF_TWI_Type, TASKS_STOP),    ///< Stop TWI transaction.
      NRF_TWI_TASK_SUSPEND = offsetof(NRF_TWI_Type, TASKS_SUSPEND), ///< Suspend TWI transaction.
      NRF_TWI_TASK_RESUME  = offsetof(NRF_TWI_Type, TASKS_RESUME)   ///< Resume TWI transaction.
      /*lint -restore*/
  } nrf_twi_task_t;
  
  /**
   * @brief TWI events.
   */
  typedef enum
  {
      /*lint -save -e30*/
      NRF_TWI_EVENT_STOPPED   = offsetof(NRF_TWI_Type, EVENTS_STOPPED),  ///< TWI stopped.
      NRF_TWI_EVENT_RXDREADY  = offsetof(NRF_TWI_Type, EVENTS_RXDREADY), ///< TWI RXD byte received.
      NRF_TWI_EVENT_TXDSENT   = offsetof(NRF_TWI_Type, EVENTS_TXDSENT),  ///< TWI TXD byte sent.
      NRF_TWI_EVENT_ERROR     = offsetof(NRF_TWI_Type, EVENTS_ERROR),    ///< TWI error.
      NRF_TWI_EVENT_BB        = offsetof(NRF_TWI_Type, EVENTS_BB),       ///< TWI byte boundary, generated before each byte that is sent or received.
      NRF_TWI_EVENT_SUSPENDED = offsetof(NRF_TWI_Type, EVENTS_SUSPENDED) ///< TWI entered the suspended state.
      /*lint -restore*/
  } nrf_twi_event_t;
  
  /**
   * @brief TWI shortcuts.
   */
  typedef enum
  {
      NRF_TWI_SHORT_BB_SUSPEND_MASK = TWI_SHORTS_BB_SUSPEND_Msk, ///< Shortcut between BB event and SUSPEND task.
      NRF_TWI_SHORT_BB_STOP_MASK    = TWI_SHORTS_BB_STOP_Msk,    ///< Shortcut between BB event and STOP task.
  } nrf_twi_short_mask_t;
  
  /**
   * @brief TWI interrupts.
   */
  typedef enum
  {
      NRF_TWI_INT_STOPPED_MASK    = TWI_INTENSET_STOPPED_Msk,  ///< Interrupt on STOPPED event.
      NRF_TWI_INT_RXDREADY_MASK   = TWI_INTENSET_RXDREADY_Msk, ///< Interrupt on RXDREADY event.
      NRF_TWI_INT_TXDSENT_MASK    = TWI_INTENSET_TXDSENT_Msk,  ///< Interrupt on TXDSENT event.
      NRF_TWI_INT_ERROR_MASK      = TWI_INTENSET_ERROR_Msk,    ///< Interrupt on ERROR event.
      NRF_TWI_INT_BB_MASK         = TWI_INTENSET_BB_Msk,       ///< Interrupt on BB event.
      NRF_TWI_INT_SUSPENDED_MASK  = TWI_INTENSET_SUSPENDED_Msk ///< Interrupt on SUSPENDED event.
  } nrf_twi_int_mask_t;
  
  /**
   * @brief TWI error source.
   */
  typedef enum
  {
      NRF_TWI_ERROR_ADDRESS_NACK = TWI_ERRORSRC_ANACK_Msk,  ///< NACK received after sending the address.
      NRF_TWI_ERROR_DATA_NACK    = TWI_ERRORSRC_DNACK_Msk,  ///< NACK received after sending a data byte.
      NRF_TWI_ERROR_OVERRUN      = TWI_ERRORSRC_OVERRUN_Msk ///< Overrun error.
                                                            /**< A new byte was received before the previous byte was read
                                                             *   from the RXD register (previous data is lost). */
  } nrf_twi_error_t;
  
  /**
   * @brief TWI master clock frequency.
   */
  typedef enum
  {
      NRF_TWI_FREQ_100K = TWI_FREQUENCY_FREQUENCY_K100, ///< 100 kbps.
      NRF_TWI_FREQ_250K = TWI_FREQUENCY_FREQUENCY_K250, ///< 250 kbps.
      NRF_TWI_FREQ_400K = TWI_FREQUENCY_FREQUENCY_K400  ///< 400 kbps.
  } nrf_twi_frequency_t;
  
  
  /**
   * @brief Function for activating a specific TWI task.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   * @param[in] task  Task to activate.
   */
  __STATIC_INLINE void nrf_twi_task_trigger(NRF_TWI_Type * p_reg,
                                            nrf_twi_task_t task);
  
  /**
   * @brief Function for getting the address of a specific TWI task register.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   * @param[in] task  Requested task.
   *
   * @return Address of the specified task register.
   */
  __STATIC_INLINE uint32_t * nrf_twi_task_address_get(NRF_TWI_Type * p_reg,
                                                      nrf_twi_task_t task);
  
  /**
   * @brief Function for clearing a specific TWI event.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   * @param[in] event Event to clear.
   */
  __STATIC_INLINE void nrf_twi_event_clear(NRF_TWI_Type * p_reg,
                                           nrf_twi_event_t event);
  
  /**
   * @brief Function for checking the state of a specific event.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   * @param[in] event Event to check.
   *
   * @retval true If the event is set.
   * @retval false If the event is not set.
   */
  __STATIC_INLINE bool nrf_twi_event_check(NRF_TWI_Type  * p_reg,
                                           nrf_twi_event_t event);
  
  /**
   * @brief Function for getting the address of a specific TWI event register.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   * @param[in] event Requested event.
   *
   * @return Address of the specified event register.
   */
  __STATIC_INLINE uint32_t * nrf_twi_event_address_get(NRF_TWI_Type  * p_reg,
                                                       nrf_twi_event_t event);
  
  /**
   * @brief Function for enabling specified shortcuts.
   *
   * @param[in] p_reg       Pointer to the peripheral registers structure.
   * @param[in] shorts_mask Shortcuts to enable.
   */
  __STATIC_INLINE void nrf_twi_shorts_enable(NRF_TWI_Type * p_reg,
                                             uint32_t shorts_mask);
  
  /**
   * @brief Function for disabling specified shortcuts.
   *
   * @param[in] p_reg       Pointer to the peripheral registers structure.
   * @param[in] shorts_mask Shortcuts to disable.
   */
  __STATIC_INLINE void nrf_twi_shorts_disable(NRF_TWI_Type * p_reg,
                                              uint32_t shorts_mask);
  
  /**
   * @brief Function for enabling specified interrupts.
   *
   * @param[in] p_reg    Pointer to the peripheral registers structure.
   * @param[in] int_mask Interrupts to enable.
   */
  __STATIC_INLINE void nrf_twi_int_enable(NRF_TWI_Type * p_reg,
                                          uint32_t int_mask);
  
  /**
   * @brief Function for disabling specified interrupts.
   *
   * @param[in] p_reg    Pointer to the peripheral registers structure.
   * @param[in] int_mask Interrupts to disable.
   */
  __STATIC_INLINE void nrf_twi_int_disable(NRF_TWI_Type * p_reg,
                                           uint32_t int_mask);
  
  /**
   * @brief Function for retrieving the state of a given interrupt.
   *
   * @param[in] p_reg    Pointer to the peripheral registers structure.
   * @param[in] int_mask Interrupt to check.
   *
   * @retval true  If the interrupt is enabled.
   * @retval false If the interrupt is not enabled.
   */
  __STATIC_INLINE bool nrf_twi_int_enable_check(NRF_TWI_Type * p_reg,
                                                nrf_twi_int_mask_t int_mask);
  
  /**
   * @brief Function for enabling the TWI peripheral.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   */
  __STATIC_INLINE void nrf_twi_enable(NRF_TWI_Type * p_reg);
  
  /**
   * @brief Function for disabling the TWI peripheral.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   */
  __STATIC_INLINE void nrf_twi_disable(NRF_TWI_Type * p_reg);
  
  /**
   * @brief Function for configuring TWI pins.
   *
   *
   * @param[in] p_reg   Pointer to the peripheral registers structure.
   * @param[in] scl_pin SCL pin number.
   * @param[in] sda_pin SDA pin number.
   */
  __STATIC_INLINE void nrf_twi_pins_set(NRF_TWI_Type * p_reg,
                                        uint32_t scl_pin,
                                        uint32_t sda_pin);
  
  /**
   * @brief Function for setting the TWI master clock frequency.
   *
   * @param[in] p_reg     Pointer to the peripheral registers structure.
   * @param[in] frequency TWI frequency.
   */
  __STATIC_INLINE void nrf_twi_frequency_set(NRF_TWI_Type * p_reg,
                                             nrf_twi_frequency_t frequency);
  
  /**
   * @brief Function for checking the TWI error source.
   *
   * The error flags are cleared after reading.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   *
   * @return Mask with error source flags.
   */
  __STATIC_INLINE uint32_t nrf_twi_errorsrc_get_and_clear(NRF_TWI_Type * p_reg);
  
  /**
   * @brief Function for setting the address to be used in TWI transfers.
   *
   * @param[in] p_reg   Pointer to the peripheral registers structure.
   * @param[in] address Address to be used in transfers.
   */
  __STATIC_INLINE void nrf_twi_address_set(NRF_TWI_Type * p_reg, uint8_t address);
  
  /**
   * @brief Function for reading data received by TWI.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   *
   * @return Received data.
   */
  __STATIC_INLINE uint8_t nrf_twi_rxd_get(NRF_TWI_Type * p_reg);
  
  /**
   * @brief Function for writing data to be transmitted by TWI.
   *
   * @param[in] p_reg Pointer to the peripheral registers structure.
   * @param[in] data  Data to be transmitted.
   */
  __STATIC_INLINE void nrf_twi_txd_set(NRF_TWI_Type * p_reg, uint8_t data);
  
  __STATIC_INLINE void nrf_twi_shorts_set(NRF_TWI_Type * p_reg,
                                          uint32_t shorts_mask);
  
  /**
   * @}
   */
  
  
  #ifndef SUPPRESS_INLINE_IMPLEMENTATION
  
  __STATIC_INLINE void nrf_twi_task_trigger(NRF_TWI_Type * p_reg,
                                            nrf_twi_task_t task)
  {
      *((volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)task)) = 0x1UL;
  }
  
  __STATIC_INLINE uint32_t * nrf_twi_task_address_get(NRF_TWI_Type * p_reg,
                                                      nrf_twi_task_t task)
  {
      return (uint32_t *)((uint8_t *)p_reg + (uint32_t)task);
  }
  
  __STATIC_INLINE void nrf_twi_event_clear(NRF_TWI_Type  * p_reg,
                                           nrf_twi_event_t event)
  {
      *((volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event)) = 0x0UL;
  #if __CORTEX_M == 0x04
      volatile uint32_t dummy = *((volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event));
      (void)dummy;
  #endif
  }
  
  __STATIC_INLINE bool nrf_twi_event_check(NRF_TWI_Type  * p_reg,
                                           nrf_twi_event_t event)
  {
      return (bool)*(volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event);
  }
  
  __STATIC_INLINE uint32_t * nrf_twi_event_address_get(NRF_TWI_Type  * p_reg,
                                                       nrf_twi_event_t event)
  {
      return (uint32_t *)((uint8_t *)p_reg + (uint32_t)event);
  }
  
  __STATIC_INLINE void nrf_twi_shorts_enable(NRF_TWI_Type * p_reg,
                                             uint32_t shorts_mask)
  {
      p_reg->SHORTS |= shorts_mask;
  }
  
  __STATIC_INLINE void nrf_twi_shorts_disable(NRF_TWI_Type * p_reg,
                                              uint32_t shorts_mask)
  {
      p_reg->SHORTS &= ~(shorts_mask);
  }
  
  __STATIC_INLINE void nrf_twi_int_enable(NRF_TWI_Type * p_reg,
                                          uint32_t int_mask)
  {
      p_reg->INTENSET = int_mask;
  }
  
  __STATIC_INLINE void nrf_twi_int_disable(NRF_TWI_Type * p_reg,
                                           uint32_t int_mask)
  {
      p_reg->INTENCLR = int_mask;
  }
  
  __STATIC_INLINE bool nrf_twi_int_enable_check(NRF_TWI_Type * p_reg,
                                                nrf_twi_int_mask_t int_mask)
  {
      return (bool)(p_reg->INTENSET & int_mask);
  }
  
  __STATIC_INLINE void nrf_twi_enable(NRF_TWI_Type * p_reg)
  {
      p_reg->ENABLE = (TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos);
  }
  
  __STATIC_INLINE void nrf_twi_disable(NRF_TWI_Type * p_reg)
  {
      p_reg->ENABLE = (TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos);
  }
  
  __STATIC_INLINE void nrf_twi_pins_set(NRF_TWI_Type * p_reg,
                                        uint32_t scl_pin,
                                        uint32_t sda_pin)
  {
  #if defined(TWI_PSEL_SCL_CONNECT_Pos)
      p_reg->PSEL.SCL = scl_pin;
  #else
      p_reg->PSELSCL = scl_pin;
  #endif
  
  #if defined(TWI_PSEL_SDA_CONNECT_Pos)
      p_reg->PSEL.SDA = sda_pin;
  #else
      p_reg->PSELSDA = sda_pin;
  #endif
  }
  
  __STATIC_INLINE void nrf_twi_frequency_set(NRF_TWI_Type * p_reg,
                                             nrf_twi_frequency_t frequency)
  {
      p_reg->FREQUENCY = frequency;
  }
  
  __STATIC_INLINE uint32_t nrf_twi_errorsrc_get_and_clear(NRF_TWI_Type * p_reg)
  {
      uint32_t error_source = p_reg->ERRORSRC;
  
      // [error flags are cleared by writing '1' on their position]
      p_reg->ERRORSRC = error_source;
  
      return error_source;
  }
  
  __STATIC_INLINE void nrf_twi_address_set(NRF_TWI_Type * p_reg, uint8_t address)
  {
      p_reg->ADDRESS = address;
  }
  
  __STATIC_INLINE uint8_t nrf_twi_rxd_get(NRF_TWI_Type * p_reg)
  {
      return (uint8_t)p_reg->RXD;
  }
  
  __STATIC_INLINE void nrf_twi_txd_set(NRF_TWI_Type * p_reg, uint8_t data)
  {
      p_reg->TXD = data;
  }
  
  __STATIC_INLINE void nrf_twi_shorts_set(NRF_TWI_Type * p_reg,
                                          uint32_t shorts_mask)
  {
      p_reg->SHORTS = shorts_mask;
  }
  
  #endif // SUPPRESS_INLINE_IMPLEMENTATION
  
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif // NRF_TWI_H__
  