STM32CubeF0/Projects/STM32072B_EVAL/Applications/FreeRTOS/FreeRTOS_Semaphore/readme.txt

/**
  @page FreeRTOS_Semaphore FreeRTOS Semaphore example
 
  @verbatim
  ******************************************************************************
  * @file    FreeRTOS/FreeRTOS_Semaphore/readme.txt
  * @author  MCD Application Team
  * @brief   Description of the FreeRTOS Semaphore example.
  ******************************************************************************
  *
  * Copyright (c) 2016 STMicroelectronics International N.V. All rights reserved.
  *
  * 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.
  *
  ******************************************************************************
  @endverbatim

@par Application Description

This application shows how to use semaphores with CMSIS RTOS API .

This example creates two threads that toggle LEDs through a shared semaphore,
as following:

The first thread which have the higher priority obtains the semaphore and 
toggle the LED1 each 200 ms. After 5 seconds it releases the semaphore and 
suspends itself.

The low priority thread can execute now, it obtains the semaphore and 
resume execution of the first thread, as it has the higher priority
the first thread will try to obtain the semaphore but it fails because
the semaphore is already taken by the low priority thread, which will
toggle the LED2 each 200 ms for 5 seconds before releasing the semaphore
to begin a new cycle

@note Care must be taken when using HAL_Delay(), this function provides accurate
      delay (in milliseconds) based on variable incremented in HAL time base ISR.
      This implies that if HAL_Delay() is called from a peripheral ISR process, then
      the HAL time base interrupt must have higher priority (numerically lower) than
      the peripheral interrupt. Otherwise the caller ISR process will be blocked.
      To change the HAL time base interrupt priority you have to use HAL_NVIC_SetPriority()
      function.
 
@note The application needs to ensure that the HAL time base is always set to 1 millisecond
      to have correct HAL operation.

@note The FreeRTOS heap size configTOTAL_HEAP_SIZE defined in FreeRTOSConfig.h is set accordingly to the 
      OS resources memory requirements of the application with +10% margin and rounded to the upper Kbyte boundary.

For more details about FreeRTOS implementation on STM32Cube, please refer to UM1722 "Developing Applications 
on STM32Cube with RTOS".


@par Directory contents
    - FreeRTOS/FreeRTOS_Semaphore/Src/main.c                       Main program
    - FreeRTOS/FreeRTOS_Semaphore/Src/stm32f0xx_hal_timebase_tim.c HAL timebase file
    - FreeRTOS/FreeRTOS_Semaphore/Src/stm32f0xx_it.c               Interrupt handlers
    - FreeRTOS/FreeRTOS_Semaphore/Src/system_stm32f0xx.c           STM32F0xx system clock configuration file
    - FreeRTOS/FreeRTOS_Semaphore/Inc/main.h                       Main program header file
    - FreeRTOS/FreeRTOS_Semaphore/Inc/stm32f0xx_hal_conf.h         HAL Library Configuration file
    - FreeRTOS/FreeRTOS_Semaphore/Inc/stm32f0xx_it.h               Interrupt handlers header file
    - FreeRTOS/FreeRTOS_Semaphore/Inc/FreeRTOSConfig.h             FreeRTOS Configuration file

@par Hardware and Software environment

  - This example runs on STM32F072xB devices.
    
  - This example has been tested with STM32072B-EVAL RevB board and can be
    easily tailored to any other supported device and development board.
    

@par How to use it ?

In order to make the program work, you must do the following:
 - Open your preferred toolchain 
 - Rebuild all files and load your image into target memory
 - Run the example
  
 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */