text: /**
   * \file
   * \brief ATCA Hardware abstraction layer for SAM4S I2C over ASF drivers.
   *
   * Prerequisite: add "TWI - Two-Wire Interface (Common API) (service)" module to application in Atmel Studio
   *
   * \copyright (c) 2015-2018 Microchip Technology Inc. and its subsidiaries.
   *
   * \page License
   *
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   * and any derivatives exclusively with Microchip products. It is your
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   * use of third party software (including open source software) that may
   * accompany Microchip software.
   *
   * THIS SOFTWARE IS SUPPLIED BY MICROCHIP "AS IS". NO WARRANTIES, WHETHER
   * EXPRESS, IMPLIED OR STATUTORY, APPLY TO THIS SOFTWARE, INCLUDING ANY IMPLIED
   * WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY, AND FITNESS FOR A
   * PARTICULAR PURPOSE. IN NO EVENT WILL MICROCHIP BE LIABLE FOR ANY INDIRECT,
   * SPECIAL, PUNITIVE, INCIDENTAL OR CONSEQUENTIAL LOSS, DAMAGE, COST OR EXPENSE
   * OF ANY KIND WHATSOEVER RELATED TO THE SOFTWARE, HOWEVER CAUSED, EVEN IF
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   */
  
  #ifndef HAL_SAM4S_I2C_ASF_H_
  #define HAL_SAM4S_I2C_ASF_H_
  
  #include <asf.h>
  
  
  /**
   * \defgroup hal_ Hardware abstraction layer (hal_)
   *
   * \brief
   * These methods define the hardware abstraction layer for communicating with a CryptoAuth device
   * using I2C driver of ASF.
   *
     @{ */
  
  #define MAX_I2C_BUSES   2   // SAM4S has 2 TWI
  
  /**
   * \brief this is the hal_data for ATCA HAL
   */
  typedef struct atcaI2Cmaster
  {
      uint32_t twi_id;
      Twi *    twi_master_instance;
      int      ref_ct;
      // for conveniences during interface release phase
      int bus_index;
  } ATCAI2CMaster_t;
  
  void change_i2c_speed(ATCAIface iface, uint32_t speed);
  
  /** @} */
  
  #endif  /* HAL_SAM4S_I2C_ASF_H_ */