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103 lines
4.7 KiB
Plaintext
103 lines
4.7 KiB
Plaintext
/**
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@page TIM_TimeBase TIM_TimeBase example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file TIM/TIM_TimeBase/readme.txt
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* @author MCD Application Team
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* @brief Description of the TIM Time Base example
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******************************************************************************
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. Neither the name of STMicroelectronics nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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This example shows how to configure the TIM peripheral to generate a time base of
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one second with the corresponding Interrupt request.
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In this example TIM3 input clock (TIM3CLK) is set to 2 * APB1 clock (PCLK1),
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since APB1 prescaler is different from 1.
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TIM3CLK = 2 * PCLK1
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PCLK1 = HCLK / 2
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=> TIM3CLK = HCLK = SystemCoreClock (Hz)
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To get TIM3 counter clock at 10 KHz, the Prescaler is computed as following:
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- Prescaler = (TIM3CLK / TIM3 counter clock) - 1
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SystemCoreClock is set to 168MHz for STM32F4xx Devices.
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The TIM3 ARR register value is equal to 10000 - 1,
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Update rate = TIM3 counter clock / (Period + 1) = 1 Hz,
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So the TIM3 generates an interrupt each 1 s
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When the counter value reaches the auto-reload register value, the TIM upadate
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interrupt is generated and, in the handler routine, PD.12 is toggled with the
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following frequency:
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- PD.12: 0.5Hz
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then 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 The application 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 Directory contents
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- TIM/TIM_TimeBase/Inc/stm32f4xx_hal_conf.h HAL configuration file
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- TIM/TIM_TimeBase/Inc/stm32f4xx_it.h Interrupt handlers header file
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- TIM/TIM_TimeBase/Inc/main.h Main program header file
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- TIM/TIM_TimeBase/Src/stm32f4xx_it.c Interrupt handlers
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- TIM/TIM_TimeBase/Src/main.c Main program
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- TIM/TIM_TimeBase/Src/stm32f4xx_hal_msp.c HAL MSP module
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- TIM/TIM_TimeBase/Src/system_stm32f4xx.c STM32F4xx system clock configuration file
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@par Hardware and Software environment
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- This example runs on STM32F401xCx devices.
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- This example has been tested with STM32F401-Discovery RevB board (MB1115B)and can be
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easily tailored to any other supported device and development board.
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- STM32F401-Discovery RevB board (MB1115B) Set-up
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- Use LED4(GREEN) connected respectively PD.12 pin and connect it on an
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oscilloscope to show the different Time Base signals.
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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 toolchain
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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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