text: /*-----------------------------------------------------------------------------
   * Name:    Buttons_STM32F030-Discovery.c
   * Purpose: Buttons interface for STM32F030-Discovery evaluation board
   * Rev.:    1.00
   *----------------------------------------------------------------------------*/
  
  /* Copyright (c) 2013 - 2015 ARM LIMITED
  
     All rights reserved.
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions are met:
     - Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
     - Redistributions in binary form 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.
     - Neither the name of ARM nor the names of its contributors may be used
       to endorse or promote products derived from this software without
       specific prior written permission.
     *
     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 COPYRIGHT HOLDERS AND 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.
     ---------------------------------------------------------------------------*/
  
  #include "stm32f0xx.h"                  // Device header
  #include "Board_Buttons.h"              // ::Board Support:Buttons
  
  #define NUM_KEYS  1                     /* Number of available keys           */
  
  /* Keys for STM32F030-Discovery Board */
  #define USER    1
  
  
  /**
    \fn          int32_t Buttons_Initialize (void)
    \brief       Initialize buttons
    \returns
     - \b  0: function succeeded
     - \b -1: function failed
  */
  int32_t Buttons_Initialize (void) {
  
    RCC->AHBENR  |= ((1UL << 17) );               /* Enable GPIOA clock         */
  
    GPIOA->MODER    &= ~((3UL << 2*0)  );         /* PA.0 is input              */
    GPIOA->OSPEEDR  &= ~((3UL << 2*0)  );         /* PA.0 is Low Speed          */
    GPIOA->PUPDR    &= ~((3UL << 2*0)  );         /* PA.0 is no Pull up         */
  
    return (0);
  }
  
  
  /**
    \fn          int32_t Buttons_Uninitialize (void)
    \brief       De-initialize buttons
    \returns
     - \b  0: function succeeded
     - \b -1: function failed
  */
  int32_t Buttons_Uninitialize (void) {
  
    GPIOA->MODER    &= ~((3UL << 2*0)  );
  
    return (0);
  }
  
  
  /**
    \fn          uint32_t Buttons_GetState (void)
    \brief       Get buttons state
    \returns     Buttons state
  */
  uint32_t Buttons_GetState (void) {
  
    uint32_t val = 0;
  
    if ((GPIOA->IDR & (1ul << 0)) != 0) {
      /* USER button */
      val |= USER;
    }
  
    return (val);
  }
  
  
  /**
    \fn          uint32_t Buttons_GetCount (void)
    \brief       Get number of available buttons
    \return      Number of available buttons
  */
  uint32_t Buttons_GetCount (void) {
    return (NUM_KEYS);
  }
  
  