98 lines
4.1 KiB
Plaintext
98 lines
4.1 KiB
Plaintext
/**
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@page FreeRTOS_LowPower FreeRTOS Low Power example
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@verbatim
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******************************************************************************
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* @file FreeRTOS/FreeRTOS_LowPower/readme.txt
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* @author MCD Application Team
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* @brief Description of the FreeRTOS low power example.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2016 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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@endverbatim
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@par Application Description
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How to enter and exit low-power mode with CMSIS RTOS API.
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This example creates two threads.
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+ An Rx thread that blocks on a queue to wait for data, blinking the LED1 each
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time data is received (turning it on and then off again) before returning
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to block on the queue once more.
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+ A Tx thread that repeatedly enters blocked state for 500ms.
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On exiting the blocked state the Tx thread sends a value through the queue
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to the Rx thread (causing the Rx thread to exit the blocked state and blink
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the LED1).
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Blocking for a finite period allows the kernel to stop tick interrupt
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and place STM32 into Sleep mode - the lowest-power mode possible
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that allows the CPU registers and RAM to retain their state.
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In this example, non-used GPIOs are configured to analog, thus helping to reduce
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the power consumption of the device.
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Observed behaviour:
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Every 500ms the MCU will come out of the low power state to turn the LED1 on,
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then return to the low power state for 20ms before leaving the low power
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state again to turn the LED1 off. This will be observed as a fast blinking
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on the LED1.
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The RTOS tick is suppressed while the MCU is in its low power state.
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@note Care must be taken when using HAL_Delay(), this function provides accurate
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delay (in milliseconds) based on variable incremented in HAL time base ISR.
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This implies that if HAL_Delay() is called from a peripheral ISR process, then
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the HAL time base interrupt must have higher priority (numerically lower) than
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the peripheral interrupt. Otherwise the caller ISR process will be blocked.
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To change the HAL time base interrupt priority you have to use HAL_NVIC_SetPriority()
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function.
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@note The application needs to ensure that the HAL time base is always set to 1 millisecond
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to have correct HAL operation.
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@note The FreeRTOS heap size configTOTAL_HEAP_SIZE defined in FreeRTOSConfig.h is set accordingly to the
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OS resources memory requirements of the application with +10% margin and rounded to the upper Kbyte boundary.
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For more details about FreeRTOS implementation on STM32Cube, please refer to UM1722 "Developing Applications
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on STM32Cube with RTOS".
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@par Directory contents
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- FreeRTOS/FreeRTOS_LowPower/Src/main.c Main program
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- FreeRTOS/FreeRTOS_LowPower/Src/stm32f0xx_hal_timebase_tim.c HAL timebase file
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- FreeRTOS/FreeRTOS_LowPower/Src/stm32f0xx_it.c Interrupt handlers
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- FreeRTOS/FreeRTOS_LowPower/Src/system_stm32f0xx.c STM32F0xx system clock configuration file
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- FreeRTOS/FreeRTOS_LowPower/Inc/main.h Main program header file
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- FreeRTOS/FreeRTOS_LowPower/Inc/stm32f0xx_hal_conf.h HAL Library Configuration file
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- FreeRTOS/FreeRTOS_LowPower/Inc/stm32f0xx_it.h Interrupt handlers header file
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- FreeRTOS/FreeRTOS_LowPower/Inc/FreeRTOSConfig.h FreeRTOS Configuration file
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@par Hardware and Software environment
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- This example runs on STM32091xC devices.
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- This example has been tested with STM32091C-EVAL board and can be
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easily tailored to any other supported device and development board.
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@par How to use it ?
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In order to make the program work, you must do the following:
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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*/
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