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119 lines
5.6 KiB
Plaintext
119 lines
5.6 KiB
Plaintext
/**
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@page WWDG_Example Window Watchdog example
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file WWDG/WWDG_Example/readme.txt
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* @author MCD Application Team
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* @brief Description of the Window Watchdog example.
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******************************************************************************
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. Neither the name of STMicroelectronics nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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Configuration of the HAL API to periodically update the WWDG counter and simulate a software fault that
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generates an MCU WWDG reset when a predefined time period has elapsed.
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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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Then the SystemClock_Config() function is used to configure the system
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clock (SYSCLK) to run at 48 MHz.
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The WWDG peripheral configuration is ensured by the HAL_WWDG_Init() function.
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This later is calling the HAL_WWDG_MspInit()function which core is implementing
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the configuration of the needed WWDG resources according to the used hardware (CLOCK,
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GPIO, DMA and NVIC). You may update this function to change WWDG configuration.
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The WWDG timeout is set, through counter value, to 43.7 ms.
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The refresh window is set in order to make user wait 33 ms after a wadchdog refresh,
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before writing again counter. Hence the WWDG counter is refreshed each (33 + 1) ms in the
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main program infinite loop to prevent a WWDG reset.
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LED3 is toggling at same frequency, indicating that the program is running.
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An EXTI Line is connected to a GPIO pin, and configured to generate an interrupt
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on the rising edge of the signal.
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The EXTI Line is used to simulate a software failure: once the EXTI Line event
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occurs, by putting or removing a jumper between PA.12 (Arduino D2) and GND,
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the corresponding interrupt is served.
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In the ISR, a write to invalid address generates a Hardfault exception containing
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an infinite loop and preventing to return to main program (the WWDG counter is
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not refreshed).
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As a result, when the WWDG counter falls to 0x3F and WWDG reset occurs.
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If the WWDG reset is generated, after the system resumes from reset, LED3 is turned ON for 4 seconds.
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If the EXTI Line event does not occur, the WWDG counter is indefinitely refreshed
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in the main program infinite loop, and there is no WWDG reset.
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LED3 is turned OFF if any error occurs.
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@note This example must be tested in standalone mode (not in debug).
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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 SysTick ISR. This
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implies that if HAL_Delay() is called from a peripheral ISR process, then
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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 application 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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@par Directory contents
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- WWDG/WWDG_Example/Inc/stm32f0xx_hal_conf.h HAL configuration file
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- WWDG/WWDG_Example/Inc/stm32f0xx_it.h Interrupt handlers header file
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- WWDG/WWDG_Example/Inc/main.h Header for main.c module
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- WWDG/WWDG_Example/Src/stm32f0xx_it.c Interrupt handlers
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- WWDG/WWDG_Example/Src/main.c Main program
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- WWDG/WWDG_Example/Src/stm32f0xx_hal_msp.c HAL MSP file
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- WWDG/WWDG_Example/Src/system_stm32f0xx.c STM32F0xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F042x6 devices.
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- This example has been tested with STM32F042K6-Nucleo(revC) 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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* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
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*/
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