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/**
@page COMP_CompareGpioVsVrefInt_IT_Init COMP example
@verbatim
******************************************************************************
* @file Examples_LL/COMP/COMP_CompareGpioVsVrefInt_IT_Init/readme.txt
* @author MCD Application Team
* @brief Description of the COMP_CompareGpioVsVrefInt_IT_Init example.
******************************************************************************
*
* Copyright (c) 2019-2021 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
How to use a comparator peripheral to compare a voltage level applied on a GPIO
pin to the the internal voltage reference (VREFINT), in interrupt mode. This example
is based on the STM32WBxx COMP LL API. The peripheral initialization
uses the LL initialization function to demonstrate LL init usage.
Example configuration:
Comparator instance COMP1 is configured to compare:
- input plus set to a GPIO pin (cf pin below) in analog mode.
- input minus set to internal voltage reference VrefInt (voltage level 1.2V,
refer to device datasheet for min/typ/max values)
Comparator interruption is enabled through EXTI line 20 with trigger edge
set to both edges rising and falling.
Comparator is set in power mode ultra low power.
Example execution:
From the main program execution, comparator is enabled.
Each time the voltage level applied on GPIO pin (comparator input plus)
is crossing VrefInt voltage threshold (comparator input minus),
the comparator generates an interruption.
LED2 is turned on or off depending on comparator output state:
turned on if comparator voltage level on input plus is higher than input minus,
turned-off otherwise.
Connection needed:
A voltage must be supplied to the analog input pin (cf pin below),
between 0V and Vdda=3.3V. Otherwise this pin can be let floating (but in this
case COMP comparison level will be undetermined).
To check comparator threshold, you can:
- Either use a wire to connect the GPIO pin of comparator input (cf pin below)
to other connectors on board:
- below comparator threshold: to ground
- above comparator threshold: to voltage of power supply Vdda
(on board Nucleo: by default, Vdda connected to 3.3V)
- Either use an external power supply
Other peripheral used:
1 GPIO for LED2
1 GPIO for analog input of comparator: PC.05 (Morpho connector CN7 pin 3)
EXTI line 20 (connected to COMP1 output)
@par Keywords
Comparator, COMP, analog, voltage, analog input, threshold, VrefInt
@par Directory contents
- COMP/COMP_CompareGpioVsVrefInt_IT_Init/Inc/stm32wbxx_it.h Interrupt handlers header file
- COMP/COMP_CompareGpioVsVrefInt_IT_Init/Inc/main.h Header for main.c module
- COMP/COMP_CompareGpioVsVrefInt_IT_Init/Inc/stm32_assert.h Template file to include assert_failed function
- COMP/COMP_CompareGpioVsVrefInt_IT_Init/Src/stm32wbxx_it.c Interrupt handlers
- COMP/COMP_CompareGpioVsVrefInt_IT_Init/Src/main.c Main program
- COMP/COMP_CompareGpioVsVrefInt_IT_Init/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB55RGVx devices.
- This example has been tested with P-NUCLEO-WB55 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>
*/
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