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diff --git a/Projects/NUCLEO-WB35CE/Examples/HAL/HAL_TimeBase_RTC_WKUP/readme.txt b/Projects/NUCLEO-WB35CE/Examples/HAL/HAL_TimeBase_RTC_WKUP/readme.txt new file mode 100644 index 000000000..ec37c97c8 --- /dev/null +++ b/Projects/NUCLEO-WB35CE/Examples/HAL/HAL_TimeBase_RTC_WKUP/readme.txt @@ -0,0 +1,93 @@ +/** + @page HAL_TimeBase_RTC_WKUP HAL TimeBase RTC WakeUp + + @verbatim + ****************************************************************************** + * @file HAL/HAL_TimeBase_RTC_WAKUP/readme.txt + * @author MCD Application Team + * @brief Description of the HAL TimeBase RTC WakeUp example. + ****************************************************************************** + * + * Copyright (c) 2019 STMicroelectronics. All rights reserved. + * + * This software component is licensed by ST under BSD 3-Clause license, + * the "License"; You may not use this file except in compliance with the + * License. You may obtain a copy of the License at: + * opensource.org/licenses/BSD-3-Clause + * + ****************************************************************************** + @endverbatim + +@par Example Description + +How to customize HAL using RTC wakeup as main source of time base, +instead of Systick. + +The User push-button (SW1) is used to suspend or resume tick increment. + +Each time the button is pressed; an interrupt is generated (External line 0) +and in the ISR the uwIncrementState is checked: + 1- If the uwIncrementState = 0: the tick increment is suspended by calling + HAL_SuspendTick() API (RTC wakeup timer interrupt is disabled). + 2- If the uwIncrementState = 1: the tick increment is Resumed by calling + HAL_ResumeTick() API(RTC wakeup timer interrupt is enabled). + +The wakeup feature is configured to assert an interrupt each 1ms + +The example brings, in user file, a new implementation of the following HAL weak functions: + +HAL_InitTick() +HAL_SuspendTick() +HAL_ResumeTick() + +This implementation will overwrite native implementation in stm32wbxx_hal.c +and so user functions will be invoked instead when called. + +The following time base functions are kept as implemented natively: + +HAL_IncTick() +HAL_Delay() + +In an infinite loop, LED2 toggles spaced out over 500ms delay, except when tick increment is suspended. + +@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. + +@par Keywords + +System, RTC Wakeup, Time base, HAL + +@par Directory contents + + - HAL/HAL_TimeBase_RTC_WKUP/Inc/stm32wbxx_hal_conf.h HAL configuration file + - HAL/HAL_TimeBase_RTC_WKUP/Inc/stm32wbxx_it.h Interrupt handlers header file + - HAL/HAL_TimeBase_RTC_WKUP/Inc/main.h Header for main.c module + - HAL/HAL_TimeBase_RTC_WKUP/Src/stm32wbxx_it.c Interrupt handlers + - HAL/HAL_TimeBase_RTC_WKUP/Src/main.c Main program + - HAL/HAL_TimeBase_RTC_WKUP/Src/stm32wbxx_hal_msp.c HAL MSP file + - HAL/HAL_TimeBase_RTC_WKUP/Src/stm32wbxx_hal_timebase_rtc_wakeup.c HAL time base functions + - HAL/HAL_TimeBase_RTC_WKUP/Src/system_stm32wbxx.c STM32WBxx system source file + +@par Hardware and Software environment + + - This example runs on STM32WB35CEUx devices. + + - This example has been tested with STMicroelectronics NUCLEO-WB35CE board and can be + easily tailored to any other supported device and development board. + +@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 + + * <h3><center>© COPYRIGHT STMicroelectronics</center></h3> + */ |