105 lines
4.8 KiB
Plaintext
105 lines
4.8 KiB
Plaintext
/**
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@page HAL_TimeBase_RTC_ALARM HAL TimeBase RTC Alarm example
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@verbatim
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******************************************************************************
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* @file HAL/HAL_TimeBase_RTC_ALARM/readme.txt
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* @author MCD Application Team
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* @brief Description of the HAL TimeBase RTC Alarm 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 Example Description
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This example describes how to customize the HAL time base using RTC alarm instead
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of Systick as main source of time base. The User push-button (connected to EXTI Line[15:10])
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will be used to Suspend or Resume tick increment.
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Each time, the User push-button is pressed; EXTI15_10 interrupt is generated and in the ISR
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the uwIncrementState is checked:
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1- If the uwIncrementState = 0: the tick increment is suspended by calling
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HAL_SuspendTick() API (RTC alarm interrupt is disabled).
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2- If the uwIncrementState = 1: the tick increment is Resumed by calling
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HAL_ResumeTick() API(RTC alarm interrupt is enabled).
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The alarm is configured to assert an interrupt when the RTC reaches 1 ms
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The example brings, in user file, a new implementation of the following HAL weak functions:
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HAL_InitTick()
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HAL_SuspendTick()
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HAL_ResumeTick()
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This implementation will overwrite native implementation in stm32f7xx_hal.c
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and so user functions will be invoked instead when called.
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The following time base functions are kept as implemented natively:
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HAL_IncTick()
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HAL_Delay()
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When user pushes the User push-button, the Tick increment is suspended if it is already
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enabled, else it will be resumed.
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In an infinite loop, LED1 toggles spaced out over 1s delay.
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in HAL time base ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the HAL time base interrupt must have higher priority (numerically lower)
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than 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() 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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@par Keywords
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System, RTC Alarm, Time base, HAL
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@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,
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<20><><EFBFBD><EFBFBD><EFBFBD>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
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<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).
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@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Even though the user must manage the cache coherence for read accesses.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>
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@par Directory contents
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- HAL/HAL_TimeBase_RTC_ALARM/Inc/stm32f7xx_hal_conf.h HAL configuration file
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- HAL/HAL_TimeBase_RTC_ALARM/Inc/stm32f7xx_it.h Interrupt handlers header file
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- HAL/HAL_TimeBase_RTC_ALARM/Inc/main.h Header for main.c module
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- HAL/HAL_TimeBase_RTC_ALARM/Src/stm32f7xx_it.c Interrupt handlers
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- HAL/HAL_TimeBase_RTC_ALARM/Src/main.c Main program
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- HAL/HAL_TimeBase_RTC_ALARM/Src/stm32f7xx_hal_timebase_rtc_alarm.c HAL time base functions
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- HAL/HAL_TimeBase_RTC_ALARM/Src/system_stm32f7xx.c STM32F7xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F723xx/STM32F722xx/STM32F732xx/STM32F733xx Devices.
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- This example has been tested with STMicroelectronics STM32F722ZE-Nucleo 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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