text: /**
    ******************************************************************************
    * @file    GPIO/GPIO_IOToggle_VariableFreq/Src/main.c
    * @author  MCD Application Team
    * @brief   This example describes how to configure and use GPIOs through
    *          the STM32L0xx HAL API.
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; COPYRIGHT(c) 2016 STMicroelectronics</center></h2>
    *
    * 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 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 STMicroelectronics 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 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.
    *
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "main.h"
  
  /** @addtogroup STM32L0xx_HAL_Examples
    * @{
    */
  
  /** @addtogroup GPIO_IOToggle_VariableFreq
    * @{
    */
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  static GPIO_InitTypeDef  GPIO_InitStruct;
  
  /* Private function prototypes -----------------------------------------------*/
  void SystemClock_Config(void);
  
  
  /* Private functions ---------------------------------------------------------*/
  
  /**
    * @brief  Main program
    * @param  None
    * @retval None
    */
  int main(void)
  {
    /* This sample code shows how to use GPIO HAL API to toggle LED3 IO
      in an infinite loop. */
  
    /* STM32L0xx HAL library initialization:
         - Configure the Flash prefetch, Flash preread and Buffer caches
         - Systick timer is configured by default as source of time base, but user 
               can eventually implement his proper time base source (a general purpose 
               timer for example or other time source), keeping in mind that Time base 
               duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
               handled in milliseconds basis.
         - Low Level Initialization
       */
    HAL_Init();
  
    /* Configure the system clock */
    SystemClock_Config();
    
    /* Configure LED3 */
    BSP_LED_Init(LED3);
    
    /* Configure PA.12 (Arduino D2) button */
    GPIO_InitStruct.Pin = GPIO_PIN_12;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT; 
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
      
    __HAL_RCC_GPIOA_CLK_ENABLE();
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  
    /* Switch off LED3 */
    BSP_LED_Off(LED3);
    
    /* Toggle IO in an infinite loop */
    while (1)
    {
      /* If PA.12 (Arduino D2) is connected to GND */
      if(HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_12) == GPIO_PIN_RESET) 
      {
        BSP_LED_Toggle(LED3);
        /* Insert delay 1s */
        HAL_Delay(1000);
      }
      else
      {
        /* If PA.12 (Arduino D2) is not connected */
        BSP_LED_Toggle(LED3);
        /* Insert delay 100 ms */
        HAL_Delay(100);
      }
    }
  }
  
  /**
    * @brief  System Clock Configuration
    *         The system Clock is configured as follow : 
    *            System Clock source            = HSI
    *            SYSCLK(Hz)                     = 16000000
    *            HCLK(Hz)                       = 16000000
    *            AHB Prescaler                  = 1
    *            APB1 Prescaler                 = 4
    *            APB2 Prescaler                 = 2
    *            VDD(V)                         = 3.3
    * @param  None
    * @retval None
    */
  void SystemClock_Config(void)
  {
    RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
    RCC_OscInitTypeDef RCC_OscInitStruct = {0};
    
    /* Enable HSI as source */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
    RCC_OscInitStruct.HSIState = RCC_HSI_ON;
    RCC_OscInitStruct.HSICalibrationValue= RCC_HSICALIBRATION_DEFAULT;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct)!= HAL_OK)
    {
      /* Initialization Error */
      while(1); 
    }
  
    /* Select HSI as system clock source and configure the HCLK, PCLK1 and PCLK2 
       clocks dividers */
    RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;  
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;   
    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0)!= HAL_OK)
    {
      /* Initialization Error */
      while(1); 
    }
    /* Enable Power Control clock */
    __HAL_RCC_PWR_CLK_ENABLE();
    
    /* VCore set to 1,8V */
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
   
    /* Disable Power Control clock */
    __HAL_RCC_PWR_CLK_DISABLE(); 
  }
  
  #ifdef  USE_FULL_ASSERT
  
  /**
    * @brief  Reports the name of the source file and the source line number
    *         where the assert_param error has occurred.
    * @param  file: pointer to the source file name
    * @param  line: assert_param error line source number
    * @retval None
    */
  void assert_failed(uint8_t *file, uint32_t line)
  {
    /* User can add his own implementation to report the file name and line number,
       ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  
    /* Infinite loop */
    while (1)
    {
        BSP_LED_On(LED3);
    }
  }
  #endif
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  