STM32CubeF7/Projects/STM32756G_EVAL/Applications/FreeRTOS/FreeRTOS_Mutexes/readme.txt

/**
  @page FreeRTOS_Mutexes FreeRTOS Mutexes application
 
  @verbatim
  ******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
  * @file    FreeRTOS/FreeRTOS_Mutexes/readme.txt
  * @author  MCD Application Team
  * @brief   Description of the FreeRTOS Mutexes application.
  ******************************************************************************
  *
  * @attention
  *
  * Copyright (c) 2017 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  @endverbatim

@par Description

How to use mutexes with CMSIS RTOS API.

This application creates three threads with different priorities, 
and access the same mutex

MutexHighPriorityThread() has the highest priority so executes 
first and grabs the mutex and sleeps for a short period to let the lower 
priority threads execute.  When it has completed its demo functionality
it gives the mutex back before suspending itself. 
 
MutexMeduimPriorityThread() attempts to access the mutex by performing
a blocking 'wait'.  This thread blocks when the mutex is already taken 
by the high priority thread. It does not unblock until the highest 
priority thread  has released the mutex, and it does not actually run until 
the highest priority thread has suspended itself.
When it eventually does obtain the mutex all it does is give the mutex back
prior to also suspending itself.  At this point both the high and medium
priority threads are suspended.

MutexLowPriorityThread() runs at the idle priority.  It spins round
a tight loop attempting to obtain the mutex with a non-blocking call.  As
the lowest priority thread it will not successfully obtain the mutex until
both high and medium priority threads are suspended.  Once it eventually 
does obtain the mutex it first resume both suspended threads prior to giving
the mutex back - resulting in the low priority thread temporarily inheriting
the highest thread priority.       

Add the following variables to LiveWatch, these variables must remain equals all the time:
 - HighPriorityThreadCycles
 - MediumPriorityThreadCycles
 - LowPriorityThreadCycles

STM32 Eval board's LEDs can be used to monitor the application status:
  - LED1, LED2 and LED4 should toggle when the application runs successfully.
  - LED3 is ON when any error occurs.

@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 according 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 Keywords

RTOS, FreeRTOS, Threading, Mutexes

@Note<74>If the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
 <20><><EFBFBD><EFBFBD><EFBFBD>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>The address and the size of cacheable buffers (shared between CPU and other masters)  must be properly updated to be aligned to cache line size (32 bytes).

@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Even though the user must manage the cache coherence for read accesses.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>

@par Directory contents

    - FreeRTOS/FreeRTOS_Mutexes/Inc/main.h                Main program header file
    - FreeRTOS/FreeRTOS_Mutexes/Inc/stm32f7xx_hal_conf.h  HAL Library Configuration file
    - FreeRTOS/FreeRTOS_Mutexes/Inc/stm32f7xx_it.h        Interrupt handlers header file
    - FreeRTOS/FreeRTOS_Mutexes/Inc/FreeRTOSConfig.h      FreeRTOS Configuration file
    - FreeRTOS/FreeRTOS_Mutexes/Src/main.c                Main program
    - FreeRTOS/FreeRTOS_Mutexes/Src/stm32f7xx_it.c        Interrupt handlers


@par Hardware and Software environment

  - This application runs on STM32F756xx/STM32F746xx devices.
    
  - This example has been tested with STM327x6G_EVAL evaluation board and can be
    easily tailored to any other supported device and development board.

  - STM327x6G_EVAL Set-up
    - Ensure that JP24 is in position 2-3 to use LED1.
    - Ensure that JP23 is in position 2-3 to use LED3. 

@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
  

 */