91 lines
3.8 KiB
Plaintext
91 lines
3.8 KiB
Plaintext
/**
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@page LPTIM_PulseCounter Low power timer pulse counter example
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@verbatim
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******************************************************************************
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* @file LPTIM/LPTIM_PulseCounter/readme.txt
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* @author MCD Application Team
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* @brief Description of the LPTIM Pulse counter example
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******************************************************************************
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*
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* Copyright (c) 2020 STMicroelectronics. All rights reserved.
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*
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* This software component is licensed by ST under BSD 3-Clause license,
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* the "License"; You may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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* opensource.org/licenses/BSD-3-Clause
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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How to configure and use, through the LPTIM HAL API, the LPTIM peripheral
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to count pulses.
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To reduce power consumption, MCU enters stop mode after starting counting. Each
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time the counter reaches the maximum value (Period/Autoreload), an interruption
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is generated, the MCU is woke up from stop mode and LED2 toggles the last state.
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In this example Period value is set to 1000, so each time the counter counts
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(1000 + 1) rising edges on LPTIM Input pin PC0, an interrupt is generated and LED2
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toggles.
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In this example the internal clock provided to the LPTIM1 is LSI (32 Khz),
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so the external input is sampled with LSI clock. In order not to miss any event,
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the frequency of the changes on the external Input1 signal should never exceed the
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frequency of the internal clock provided to the LPTIM1 (LSI for the
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present example).
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@note This example can not be used in DEBUG mode, this is due to the fact
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that the Cortex-M4 core is no longer clocked during low power mode
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so debugging features are disabled.
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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 This example 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 Keywords
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Timer, Low Power, Pulse Counter, Stop mode, Interrupt
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@par Directory contents
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- LPTIM/LPTIM_PulseCounter/Inc/stm32wlxx_nucleo_conf.h BSP configuration file
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- LPTIM/LPTIM_PulseCounter/Inc/stm32wlxx_hal_conf.h HAL configuration file
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- LPTIM/LPTIM_PulseCounter/Inc/stm32wlxx_it.h Interrupt handlers header file
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- LPTIM/LPTIM_PulseCounter/Inc/main.h Header for main.c module
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- LPTIM/LPTIM_PulseCounter/Src/stm32wlxx_it.c Interrupt handlers
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- LPTIM/LPTIM_PulseCounter/Src/main.c Main program
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- LPTIM/LPTIM_PulseCounter/Src/stm32wlxx_hal_msp.c HAL MSP module
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- LPTIM/LPTIM_PulseCounter/Src/system_stm32wlxx.c STM32WLxx system source file
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@par Hardware and Software environment
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- This example runs on STM32WL55JCIx devices.
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- This example has been tested with STMicroelectronics NUCLEO-WL55JC RevC
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board and can be easily tailored to any other supported device
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and development board.
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- Generate pulses on PC0 (pin 14 in CN10 connector). (Connect a square waveform).
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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 tool chain
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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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