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/**
@page COMP_CompareGpioVsVrefInt_Window_IT_Init COMP example
@verbatim
******************************************************************************
* @file Examples_LL/COMP/COMP_CompareGpioVsVrefInt_Window_IT_Init/readme.txt
* @author MCD Application Team
* @brief Description of the COMP_CompareGpioVsVrefInt_Window_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 pair of comparator peripherals to compare a voltage level applied on
a GPIO pin to two thresholds: the internal voltage reference (VREFINT) and a fraction
of the internal voltage reference (VREFINT/2), in interrupt mode. This example is
based on the STM32WBxx COMP LL API. The peripheral initialization
uses LL unitary service functions for optimization purposes (performance and size).
Example configuration:
Comparator instances COMP1 and COMP2 are configured to work together
in window mode to compare 2 thresholds:
- COMP1 input plus set to a GPIO pin (cf pin below) in analog mode.
COMP2 input plus is not used (connected internally to the
same input plus as COMP1).
- COMP1 input minus set to internal voltage reference VrefInt
(voltage level 1.2V, refer to device datasheet for min/typ/max values)
- COMP2 input minus set to 1/2 of internal voltage reference VrefInt
(voltage level 0.6V)
Comparator interruption is enabled through EXTI lines 20 and 21
with trigger edge set to both edges rising and falling.
Comparators are 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 or 1/2 VrefInt voltage thresholds (comparator input minus),
the comparator with corresponding threshold generates an interruption.
LED2 is turned on or off depending on the pair of comparators output state:
turned on if comparator voltage level is inside the window (between VrefInt
and 1/2 VrefInt: between 1.2V and 0.6V), turned off otherwise.
Connection needed:
A voltage must be supplied to the analog input pin (cf pin below),
between Vdda=3.3V and 0V. Otherwise this pin can be let floating (but in this
case COMP comparison level will be undetermined).
To check comparator window thresholds, you must use an external power supply
to set voltage level below, above or within comparator thresholds.
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)
EXTI line 21 (connected to COMP2 output)
@par Keywords
Comparator, COMP, analog, voltage, analog input, threshold, VrefInt, window
@par Directory contents
- COMP/COMP_CompareGpioVsVrefInt_Window_IT_Init/Inc/stm32wbxx_it.h Interrupt handlers header file
- COMP/COMP_CompareGpioVsVrefInt_Window_IT_Init/Inc/main.h Header for main.c module
- COMP/COMP_CompareGpioVsVrefInt_Window_IT_Init/Inc/stm32_assert.h Template file to include assert_failed function
- COMP/COMP_CompareGpioVsVrefInt_Window_IT_Init/Src/stm32wbxx_it.c Interrupt handlers
- COMP/COMP_CompareGpioVsVrefInt_Window_IT_Init/Src/main.c Main program
- COMP/COMP_CompareGpioVsVrefInt_Window_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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