/**
@page LPTIM_PulseCounter Low power timer pulse counter example
@verbatim
******************************************************************************
* @file LPTIM/LPTIM_PulseCounter/readme.txt
* @author MCD Application Team
* @brief Description of the LPTIM Pulse counter example
******************************************************************************
*
* Copyright (c) 2020 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 configure and use, through the LPTIM HAL API, the LPTIM peripheral
to count pulses.
To reduce power consumption, MCU enters stop mode after starting counting. Each
time the counter reaches the maximum value (Period/Autoreload), an interruption
is generated, the MCU is woke up from stop mode and LED2 toggles the last state.
In this example Period value is set to 1000, so each time the counter counts
(1000 + 1) rising edges on LPTIM Input pin PC0, an interrupt is generated and LED2
toggles.
In this example the internal clock provided to the LPTIM1 is LSI (32 Khz),
so the external input is sampled with LSI clock. In order not to miss any event,
the frequency of the changes on the external Input1 signal should never exceed the
frequency of the internal clock provided to the LPTIM1 (LSI for the
present example).
@note This example can not be used in DEBUG mode, this is due to the fact
that the Cortex-M4 core is no longer clocked during low power mode
so debugging features are disabled.
@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 This example needs to ensure that the SysTick time base is always set to 1 millisecond
to have correct HAL operation.
@par Keywords
Timer, Low Power, Pulse Counter, Stop mode, Interrupt
@par Directory contents
- LPTIM/LPTIM_PulseCounter/Inc/stm32wlxx_nucleo_conf.h BSP configuration file
- LPTIM/LPTIM_PulseCounter/Inc/stm32wlxx_hal_conf.h HAL configuration file
- LPTIM/LPTIM_PulseCounter/Inc/stm32wlxx_it.h Interrupt handlers header file
- LPTIM/LPTIM_PulseCounter/Inc/main.h Header for main.c module
- LPTIM/LPTIM_PulseCounter/Src/stm32wlxx_it.c Interrupt handlers
- LPTIM/LPTIM_PulseCounter/Src/main.c Main program
- LPTIM/LPTIM_PulseCounter/Src/stm32wlxx_hal_msp.c HAL MSP module
- LPTIM/LPTIM_PulseCounter/Src/system_stm32wlxx.c STM32WLxx system source file
@par Hardware and Software environment
- This example runs on STM32WL55JCIx devices.
- This example has been tested with STMicroelectronics NUCLEO-WL55JC RevC
board and can be easily tailored to any other supported device
and development board.
- Generate pulses on PC0 (pin 14 in CN10 connector). (Connect a square waveform).
@par How to use it ?
In order to make the program work, you must do the following :
- Open your preferred tool chain
- Rebuild all files and load your image into target memory
- Run the example
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
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