/**
@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
******************************************************************************
* @attention
*
* Copyright (c) 2016 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 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 LED1 toggles the last state.
In this example Period value is set to 1000, so each time the counter counts
(1000 + 1) rising edges on LPTIM1_IN1 pin, an interrupt is generated and LED1
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 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.
@par Keywords
Timer, Low Power, Pulse Counter, Stop mode, Interrupt,
@Note<74>If the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
<20><><A0><A0><A0>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
<0A><><A0><A0><A0><A0>The address and the size of cacheable buffers (shared between CPU and other masters) must be properly updated to be aligned to cache line size (32 bytes).
@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
<0A><><A0><A0><A0> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
<0A><><A0><A0><A0><A0>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
<0A><><A0><A0><A0><A0>Even though the user must manage the cache coherence for read accesses.
<0A><><A0><A0><A0><A0>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
<0A><><A0><A0><A0><A0>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>
@par Directory contents
- LPTIM/LPTIM_PulseCounter/Inc/stm32f7xx_hal_conf.h HAL configuration file
- LPTIM/LPTIM_PulseCounter/Inc/stm32f7xx_it.h Interrupt handlers header file
- LPTIM/LPTIM_PulseCounter/Inc/main.h Header for main.c module
- LPTIM/LPTIM_PulseCounter/Src/stm32f7xx_it.c Interrupt handlers
- LPTIM/LPTIM_PulseCounter/Src/main.c Main program
- LPTIM/LPTIM_PulseCounter/Src/stm32f7xx_hal_msp.c HAL MSP module
- LPTIM/LPTIM_PulseCounter/Src/system_stm32f7xx.c STM32F7xx system source file
@par Hardware and Software environment
- This example runs on STM32F769xx/STM32F779xx/STM32F777xx/STM32F767xx devices.
- This example has been tested with STMicroelectronics STM32F769I-EVAL
board and can be easily tailored to any other supported device
and development board.
- Generate pulses on PD12 (). (Connect a square waveform).
@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
*/
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