text: /**
    ******************************************************************************
    * @file    FreeRTOS/FreeRTOS_Semaphore/Src/main.c
    * @author  MCD Application Team
    * @brief   Main program body
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics International N.V. 
    * All rights reserved.</center></h2>
    *
    * Redistribution and use in source and binary forms, with or without 
    * modification, are permitted, provided that the following conditions are met:
    *
    * 1. Redistribution 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 other 
    *    contributors to this software may be used to endorse or promote products 
    *    derived from this software without specific written permission.
    * 4. This software, including modifications and/or derivative works of this 
    *    software, must execute solely and exclusively on microcontroller or
    *    microprocessor devices manufactured by or for STMicroelectronics.
    * 5. Redistribution and use of this software other than as permitted under 
    *    this license is void and will automatically terminate your rights under 
    *    this license. 
    *
    * THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS" 
    * AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT 
    * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
    * PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
    * RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT 
    * SHALL STMICROELECTRONICS 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"
  #include "cmsis_os.h"
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  #define semtstSTACK_SIZE			configMINIMAL_STACK_SIZE
  /* Private variables ---------------------------------------------------------*/
  osThreadId SemThread1Handle, SemThread2Handle;
  osSemaphoreId osSemaphore;
  
  /* Private function prototypes -----------------------------------------------*/
  static void SemaphoreThread1(void const *argument);
  static void SemaphoreThread2(void const *argument);
  static void SystemClock_Config(void);
  static void Error_Handler(void); 
  
  /* Private functions ---------------------------------------------------------*/
  /**
    * @brief  Main program
    * @param  None
    * @retval None
    */
  int main(void)
  {
    /* STM32F4xx HAL library initialization:
         - Configure the Flash prefetch, instruction and Data caches
         - Configure the Systick to generate an interrupt each 1 msec
         - Set NVIC Group Priority to 4
         - Global MSP (MCU Support Package) initialization
       */
    HAL_Init();  
    
    /* Configure the system clock to 180 MHz */
    SystemClock_Config();
    
    /* Configure LED1 and LED3 */
    BSP_LED_Init(LED1);
    BSP_LED_Init(LED3);
  
    /* Define used semaphore */
    osSemaphoreDef(SEM);
    
    /* Create the semaphore used by the two threads. */
    osSemaphore = osSemaphoreCreate(osSemaphore(SEM) , 1);
    osSemaphoreRelease(osSemaphore);
    
    /* Create the first Thread */
    osThreadDef(SEM_Thread1, SemaphoreThread1, osPriorityLow, 0, semtstSTACK_SIZE);
    SemThread1Handle = osThreadCreate(osThread(SEM_Thread1), (void *) osSemaphore);
    
    /* Create the second Thread */
    osThreadDef(SEM_Thread2, SemaphoreThread2, osPriorityIdle, 0, semtstSTACK_SIZE);
    SemThread2Handle = osThreadCreate(osThread(SEM_Thread2), (void *) osSemaphore);
    
    /* Start scheduler */
    osKernelStart();
    
    /* We should never get here as control is now taken by the scheduler */
    for(;;);
  }
  
  /**
    * @brief  Semaphore Thread 1 function
    * @param  argument: shared semaphore
    * @retval None
    */
  static void SemaphoreThread1 (void const *argument)
  {  
    uint32_t count = 0;
    osSemaphoreId semaphore = (osSemaphoreId) argument;
    
    for(;;)
    {
      if (semaphore != NULL)
      {
        /* Try to obtain the semaphore. */
        if(osSemaphoreWait(semaphore , 100) == osOK)
        {
          count = osKernelSysTick() + 5000;
          
          while (count >= osKernelSysTick())
          {
            /* Toggle LED1 */
            BSP_LED_Toggle(LED1);
            
            /* Delay 200 ms */
            osDelay(200);
          }
          
          /* Turn off LED1 */
          BSP_LED_Off(LED1);
  
          /* Release the semaphore */
          osSemaphoreRelease(semaphore);
  
          /* Suspend ourseleves to execute thread 2 (lower priority)  */
          osThreadSuspend(NULL); 
        }
      }
    }
  }
  
  /**
    * @brief  Semaphore Thread 2 function
    * @param  argument: shared semaphore
    * @retval None
    */
  static void SemaphoreThread2 (void const *argument)
  { 
    uint32_t count = 0;
    osSemaphoreId semaphore = (osSemaphoreId) argument;
    
    for(;;)
    {
      if (semaphore != NULL)
      {
        /* Try to obtain the semaphore. */
        if(osSemaphoreWait(semaphore , 0) == osOK)
        {
          /* Resume Thread 1 (higher priority)*/
          osThreadResume(SemThread1Handle);
          
          count = osKernelSysTick() + 5000;
          
          /* Toggle LED3 every 200 ms for 5 seconds*/
          while (count >= osKernelSysTick())
          {
            BSP_LED_Toggle(LED3);
            
            osDelay(200);
          }
          
          /* Turn off LED3 */
          BSP_LED_Off(LED3);
  
          /* Release the semaphore to unblock Thread 1 (higher priority)  */
          osSemaphoreRelease(semaphore);
        }
      }
    }
  }
  
  /**
    * @brief  System Clock Configuration
    *         The system Clock is configured as follow : 
    *            System Clock source            = PLL (HSE)
    *            SYSCLK(Hz)                     = 180000000
    *            HCLK(Hz)                       = 180000000
    *            AHB Prescaler                  = 1
    *            APB1 Prescaler                 = 4
    *            APB2 Prescaler                 = 2
    *            HSE Frequency(Hz)              = 8000000
    *            PLL_M                          = 8
    *            PLL_N                          = 360
    *            PLL_P                          = 2
    *            PLL_Q                          = 7
    *            VDD(V)                         = 3.3
    *            Main regulator output voltage  = Scale1 mode
    *            Flash Latency(WS)              = 5
    * @param  None
    * @retval None
    */
  static void SystemClock_Config(void)
  {
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    RCC_OscInitTypeDef RCC_OscInitStruct;
    HAL_StatusTypeDef ret = HAL_OK;
  
    /* Enable Power Control clock */
    __HAL_RCC_PWR_CLK_ENABLE();
  
    /* The voltage scaling allows optimizing the power consumption when the device is 
       clocked below the maximum system frequency, to update the voltage scaling value 
       regarding system frequency refer to product datasheet.  */
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  
    /* Enable HSE Oscillator and activate PLL with HSE as source */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
    RCC_OscInitStruct.HSEState = RCC_HSE_ON;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
    RCC_OscInitStruct.PLL.PLLM = 8;
    RCC_OscInitStruct.PLL.PLLN = 360;
    RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
    RCC_OscInitStruct.PLL.PLLQ = 7;
    RCC_OscInitStruct.PLL.PLLR = 2;
    ret = HAL_RCC_OscConfig(&RCC_OscInitStruct);
    
    if(ret != HAL_OK)
    {
      Error_Handler();
   }
    /* activate the OverDrive to reach the 180 Mhz Frequency */  
    ret = HAL_PWREx_EnableOverDrive();
    if(ret != HAL_OK)
    {
      Error_Handler();
    }
    
    /* Select PLL 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_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;  
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;  
    ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);
    if(ret != HAL_OK)
    {
      Error_Handler();
    }
  }
  
  /**
    * @brief  This function is executed in case of error occurrence.
    * @param  None
    * @retval None
    */
  static void Error_Handler(void)
  {
    /* Turn LED3 on: Transfer Error */
    BSP_LED_On(LED3);
    while (1)
    {
    }
  }
  
  #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)
    {
    }
  }
  #endif
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  