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147 lines
7.0 KiB
Plaintext
147 lines
7.0 KiB
Plaintext
/**
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@page RTC_Alarm RTC Alarm Example
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@verbatim
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******************************************************************************
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* @file RTC/RTC_Alarm/readme.txt
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* @author MCD Application Team
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* @brief Description of the RTC Alarm example.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2018 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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How to configure and generate an RTC alarm.
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In this example, the code is executed from QSPI external memory while data is
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in internalSRAM memory.
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In this example, the Time is set to 16:30:00 and the Alarm must be generated after
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30 seconds at 16:30:30.
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Before the 30 seconds are elapsed, LED6 is toggled with a period of one second.
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It is turned ON when the RTC Alarm is generated correctly.
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The current time is updated and displayed on the debugger in aShowTime variable.
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In case of error, LED5 is toggled with a period of one second.
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At the beginning of the main program the HAL_Init() function is called to reset
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all the peripherals, initialize the Flash interface and the systick.
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The SystemClock_Config() function is used to configure the system clock.
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The RTC peripheral configuration is ensured by the HAL_RTC_Init() function.
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This latter is calling the HAL_RTC_MspInit()function which core is implementing
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the configuration of the needed RTC resources according to the used hardware (CLOCK,
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PWR, RTC clock source and Backup). You may update this function to change RTC configuration.
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@note LSE oscillator clock is used as RTC clock source by default.
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The user can use also LSI as RTC clock source. The user uncomment the adequate
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line on the main.h file.
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@code
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#define RTC_CLOCK_SOURCE_LSE
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/* #define RTC_CLOCK_SOURCE_LSI */
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@endcode
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LSI oscillator clock must be calibrated first to deliver exactly a 32 kHz signal.
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LSE (when available on board) is delivered by a 32.768 kHz crystal.
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This projects is configured for STM32F730xx devices using STM32CubeF7 HAL and running on
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STM32F7308-DISCO board from STMicroelectronics.
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@note Make sure that chosen configuration matches ExtMem_Boot configuration
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in memory.h file.
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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 SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the SysTick 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 SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
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@note The example needs to ensure that the SysTick time base is always set to 1 millisecond
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to have correct HAL operation.
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@note The STM32F7xx devices can reach a maximum clock frequency of 216MHz but as this application uses SDRAM,
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the system clock is limited to 200MHz. Indeed proper functioning of the SDRAM is only guaranteed
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at a maximum system clock frequency of 200MHz.
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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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then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
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In case of constraints it is possible to configure the MPU as "Write through/not shareable" to guarantee the cache coherence at write access but the user
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has to ensure the cache maintenance at read access though.
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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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It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
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In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
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Even though the user must manage the cache coherence for read accesses.
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Please refer to the AN4838 (Managing memory protection unit (MPU) in STM32 MCUs)
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Please refer to the AN4839 (Level 1 cache on STM32F7 Series)
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@par Keywords
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System, RTC, Alarm, wakeup timer, Backup domain, Counter, LSE, LSI
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@par Directory contents
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- "RTC/RTC_Alarm/Inc": contains the example firmware header files
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- RTC/RTC_Alarm/Inc/main.h Main configuration file
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- RTC/RTC_Alarm/Inc/stm32f7xx_it.h Interrupt handlers header file
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- RTC/RTC_Alarm/Inc/stm32f7xx_hal_conf.h HAL Configuration file
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- "RTC/RTC_Alarm/Src": contains the example firmware source files
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- RTC/RTC_Alarm/Src/main.c Main program
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- RTC/RTC_Alarm/Src/stm32f7xx_hal_msp.c Microcontroller specific packages initialization file.
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- RTC/RTC_Alarm/Src/stm32f7xx_it.c Interrupt handlers
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- RTC/RTC_Alarm/Src/system_stm32f7xx.c STM32F7xx system clock configuration file
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@par Hardware and Software environment
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- This example runs on STM32F730xx devices.
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- This example has been tested with STMicroelectronics STM32F7308-DISCO
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board and can be easily tailored to any other supported device
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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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1. Select required configuration in memory.h in Templates\ExtMem_Boot\Inc.
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The default configuration is the right one:
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- DATA_AREA set to USE_INTERNAL_SRAM
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- CODE_AREA set to USE_QSPI
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2. Program the internal Flash with the ExtMem_Boot (see below).
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3. Program the external memory with the example "Examples\RTC\RTC_Alarm" (see below).
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4. Start debugging user example or reset for free running.
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In order to load the ExtMem_Boot code :
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- Open your preferred toolchain :
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- Open the Project
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- Rebuild all files
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- Load project image
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In order to load the example "Examples\RTC\RTC_Alarm" to the external memory:
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- Open your preferred toolchain
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- Open the Project
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- Use project matching ExtMem_Boot selected configuration
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- Rebuild all files
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- Run & debug the program:
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- For an XiP configuration (eXecute in Place from QSPI):
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- Using EWARM or MDK-ARM : Load project image from the IDE (Project->Debug)
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- Using SW4STM32 :
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- Open the STM32CubeProgrammer tool
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- Select the QSPI external flash loader "MX25L512G_STM32F7308-DISCO"
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- From Erasing & Programming menu, browse and open the output binary file relative to this example
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- Load the file into the external QSPI flash using "Start Programming" at the address APPLICATION_ADDRESS (0x90000000)
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*/ |