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/**
@page COMP_CompareGpioVsVrefInt_Window_IT COMP example
@verbatim
******************************************************************************
* @file Examples/COMP/COMP_CompareGpioVsVrefInt_Window_IT/readme.txt
* @author MCD Application Team
* @brief Description of the COMP_CompareGpioVsVrefInt_Window_IT 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
This example shows how to make an analog watchdog using the COMP peripherals in window mode.
At the beginning of the main program the HAL_Init() function is called to reset all the peripherals, initialize
the Flash interface and the systick.
The SystemClock_Config() function is used to configure the system clock for STM32WB55RGVx Devices :
- The upper threshold is set to VREFINT = 1.22V
- The lower threshold is set to VREFINT / 4 = 1.22V / 4 = 0.305V
- The input voltage is configured to be connected to PA1
LEDs on P-NUCLEO-WB55 can be used to monitor the voltage level compared to comparators thresholds:
- LED1 blinks slowly (period 1 s) if input voltage is under the lower threshold.
- LED2 blinks slowly (period 1 s) if input voltage is under the higher threshold.
- If the input voltage is within the thresholds, the MCU is set in STOP mode, LEDs are turned off.
NB: The MCU wakes up from STOP mode when the input voltage is out of the thresholds window.
@note Care must be taken when using HAL_Delay(), this function provides
accurate delay (in milliseconds) based on variable incremented in SysTick ISR.
This implies that if HAL_Delay() is called from a peripheral ISR process, then
the SysTick interrupt must have higher priority (numerically lower) than the
peripheral interrupt. Otherwise the caller ISR process will be blocked.
To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
@note The application need to ensure that the SysTick time base is always set
to 1 millisecond to have correct HAL operation.
@note This example can not be used in DEBUG mode due to the fact that the Cortex-M4 core is no longer
clocked during low power mode so debugging features are disabled. Power on/off is needed to run
correctly the example.
@par Keywords
Comparator, COMP, analog, voltage, analog input, threshold, VrefInt, window
@par Directory contents
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Inc/stm32wbxx_hal_conf.h HAL configuration file
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Inc/stm32wbxx_it.h COMP interrupt handlers header file
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Inc/main.h Header for main.c module
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Src/stm32wbxx_it.c COMP interrupt handlers
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Src/main.c Main program
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Src/stm32wbxx_hal_msp.c HAL MSP file
- COMP/COMP_CompareGpioVsVrefInt_Window_IT/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB55xx devices.
- This example has been tested with P-NUCLEO-WB55 board and can be
easily tailored to any other supported device and development board.
- Apply an external variable voltage on PA1 (Arduino connector CN8 pin A2, Morpho connector CN7 pin 32) with average voltage 1.22V.
@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>
*/
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