/**
@page FreeRTOS_LowPower FreeRTOS Low Power application
@verbatim
******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
* @file FreeRTOS/FreeRTOS_LowPower/readme.txt
* @author MCD Application Team
* @brief Description of the FreeRTOS Low Power 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 enter and exit low-power mode with CMSIS RTOS API.
This application creates two threads.
+ A Rx thread that blocks on a queue to wait for data, blinking a LED each
time data is received (turning it on and then off again) before returning
to block on the queue once more.
+ A Tx thread that repeatedly enters the Blocked state for 500ms.
On exiting the blocked state the Tx thread sends a value through the queue
to the Rx thread (causing the Rx thread to exit the blocked state and blink
the LED).
Blocking for a finite period allows the kernel to stop the tick interrupt
and place the STM32 into sleep mode - the lowest power mode possible
that allows the CPU registers and RAM to retain their state.
In this application, not used GPIOs are configured to analog, this helps to reduce
the power consumption of the device
Observed behaviour:
Every 500ms the MCU will come out of the low power state to turn the LED1 on,
then return to the low power state for 20ms before leaving the low power
state again to turn the LED1 off. This will be observed as a fast blinking
on the LED1.
The RTOS tick is suppressed while the MCU is in its low power state.
@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, Low Power, Sleep mode,
@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><><A0><A0><A0>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
<0A><><A0><A0><A0><A0>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
<0A><><A0><A0><A0> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
<0A><><A0><A0><A0><A0>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
<0A><><A0><A0><A0><A0>Even though the user must manage the cache coherence for read accesses.
<0A><><A0><A0><A0><A0>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
<0A><><A0><A0><A0><A0>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>
@par Directory contents
- FreeRTOS/FreeRTOS_LowPower/Inc/main.h Main program header file
- FreeRTOS/FreeRTOS_LowPower/Inc/stm32f7xx_hal_conf.h HAL Library Configuration file
- FreeRTOS/FreeRTOS_LowPower/Inc/stm32f7xx_it.h Interrupt handlers header file
- FreeRTOS/FreeRTOS_LowPower/Inc/FreeRTOSConfig.h FreeRTOS Configuration file
- FreeRTOS/FreeRTOS_LowPower/Src/main.c Main program
- FreeRTOS/FreeRTOS_LowPower/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.
@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
*/