text: /**
   * @file    pb.h
   * @brief   Pushbutton driver header file.
   */
  /* ****************************************************************************
   * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
   *
   * 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 MAXIM INTEGRATED 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.
   *
   * Except as contained in this notice, the name of Maxim Integrated
   * Products, Inc. shall not be used except as stated in the Maxim Integrated
   * Products, Inc. Branding Policy.
   *
   * The mere transfer of this software does not imply any licenses
   * of trade secrets, proprietary technology, copyrights, patents,
   * trademarks, maskwork rights, or any other form of intellectual
   * property whatsoever. Maxim Integrated Products, Inc. retains all
   * ownership rights.
   *
   * $Date: 2018-10-31 15:32:51 +0000 (Wed, 31 Oct 2018) $
   * $Revision: 38826 $
   *
   *************************************************************************** */
  
  #ifndef _PB_H_
  #define _PB_H_
  
  #include "gpio.h"
  
  #include <stdbool.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  /**
   * @ingroup bsp
   * @defgroup pushbutton_evkit Push button driver board support
   * @{
   */
  /* **** Global Variables **** */
  extern const gpio_cfg_t pb_pin[];
  extern const unsigned int num_pbs;
  
  /* **** Function Prototypes **** */
  
  /**
   * @brief      Initialize all push buttons.
   * @return  \c #E_NO_ERROR  Push buttons initialized successfully.
   * @return     "Error Code" @ref MXC_Error_Codes "Error Code" if unsuccessful.
   *
   */
  int PB_Init(void);
  
  /**
   * Type alias @c pb_callback for the push button callback.
   * @details The function is of type:
   * @code
   *  void pb_callback(unsigned int pb, bool falling)
   * @endcode
   * To receive notification of a push button event, define a callback
   * function and pass it as a pointer to the PB_RegisterCallback(unsigned int pb, pb_callback callback) function.
   * @param      pb    push button index that triggered the callback.
   */
  typedef void (*pb_callback)(unsigned int pb, bool falling);
  
  /**
   * @brief      Register or Unregister a callback handler for events on the @p pb push button.
   * @details
   * - Calling this function with a pointer to a function @p callback, configures the pushbutton @p pb and enables the
   * interrupt to handle the push button events.
   * - Calling this function with a <tt>NULL</tt> pointer will disable the interrupt and unregister the
   * callback function.
   * @p pb must be a value between 0 and \c num_pbs.
   *
   * @param      pb        push button index to receive event callbacks.
   * @param      callback  Callback function pointer of type @c pb_callback
   * @return     #E_NO_ERROR if configured and callback registered successfully.
   * @return     "Error Code" @ref MXC_Error_Codes "Error Code" if unsuccessful.
   */
  int PB_RegisterCallback(unsigned int pb, pb_callback callback);
  
  /**
   * @brief      Register or Unregister a callback handler for rising and falling events on the @p pb push button.
   * @details
   * - Calling this function with a pointer to a function @p callback, configures the pushbutton @p pb and enables the
   * interrupt to handle the push button events.
   * - Calling this function with a <tt>NULL</tt> pointer will disable the interrupt and unregister the
   * callback function.
   * @p pb must be a value between 0 and \c num_pbs.
   *
   * @param      pb        push button index to receive event callbacks.
   * @param      callback  Callback function pointer of type @c pb_callback
   * @return     #E_NO_ERROR if configured and callback registered successfully.
   * @return     "Error Code" @ref MXC_Error_Codes "Error Code" if unsuccessful.
   */
  int PB_RegisterRiseFallCallback(unsigned int pb, pb_callback callback);
  
  /**
   * @brief   Enable a callback interrupt.
   * @note    PB_RegisterCallback must be called prior to enabling the callback interrupt.
   * @param   pb          push button index value between 0 and \c num_pbs.
   */
  void PB_IntEnable(unsigned int pb);
  
  /**
   * @brief   Disable a callback interrupt.
   * @param   pb          push button index
   */
  void PB_IntDisable(unsigned int pb);
  
  /**
   * @brief   Clear a callback interrupt.
   * @param   pb          push button index value between 0 and \c num_pbs.
   */
  void PB_IntClear(unsigned int pb);
  
  /**
   * @brief      Get the current state of the push button.
   * @param      pb     push button index value between 0 and \c num_pbs.
   * @return     TRUE   The button is pressed.
   * @return     FALSE  The button is not pressed.
   */
  int PB_Get(unsigned int pb);
  /**@}*/
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* _PB_H_ */
  