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93 lines
3.7 KiB
Plaintext
93 lines
3.7 KiB
Plaintext
/**
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@page TIM_OnePulse TIM One Pulse example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file TIM/TIM_OnePulse/readme.txt
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* @author MCD Application Team
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* @brief Description of the TIM One Pulse example.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2017 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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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 use the TIM peripheral to generate a One pulse Mode
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after a Rising edge of an external signal is received in Timer Input pin.
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TIM2CLK = SystemCoreClock/2, we want to get TIM2 counter clock at 42 MHz:
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- Prescaler = (TIM2CLK / TIM2 counter clock) - 1
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SystemCoreClock is set to 180 MHz.
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The Autoreload value is 65535 (TIM4->ARR), so the maximum frequency value to
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trigger the TIM4 input is 45000000/65535 = 687 Hz.
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The TIM4 is configured as follows:
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The One Pulse mode is used, the external signal is connected to TIM4 CH2 pin (PB.07),
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the rising edge is used as active edge, the One Pulse signal is output
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on TIM4_CH1 (PB.06).
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The TIM_Pulse defines the delay value, the delay value is fixed to:
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delay = CCR1/TIM4 counter clock = 16383 / 45000000 = 364 us.
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The (TIM_Period - TIM_Pulse) defines the One Pulse value, the pulse value is fixed to:
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One Pulse value = (TIM_Period - TIM_Pulse)/TIM4 counter clock
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= (65535 - 16383) / 45000000 = 1.092 ms.
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The one pulse waveform can be displayed using an oscilloscope.
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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 Keywords
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Timers, Output, signals, One Pulse, PWM, Oscilloscope, External signal, Autoreload, Waveform
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@par Directory contents
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- TIM/TIM_OnePulse/system_stm32f4xx.c STM32F4xx system clock configuration file
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- TIM/TIM_OnePulse/stm32f4xx_hal_conf.h HAL configuration file
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- TIM/TIM_OnePulse/stm32f4xx_it.h Interrupt handlers header file
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- TIM/TIM_OnePulse/stm32f4xx_it.c Interrupt handlers
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- TIM/TIM_OnePulse/main.c Main program
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- TIM/TIM_OnePulse/main.h Main program header file
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@par Hardware and Software environment
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- This example runs on STM32F429xx/STM32F439xx Devices.
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- This example has been tested with STM324x9I-EVAL RevB evaluation board and can be
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easily tailored to any other supported device and development board.
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- STM324x9I-EVAL RevB Set-up
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- Connect the external signal to the TIM4_CH2 pin (PB.07)
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- Connect the TIM4_CH1 (PB.06) pin to an oscilloscope to monitor the 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 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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*/
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