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90 lines
3.4 KiB
Plaintext
90 lines
3.4 KiB
Plaintext
/**
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@page TIM_DMA TIM DMA example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file TIM/TIM_DMA/readme.txt
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* @author MCD Application Team
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* @brief Description of the TIM DMA 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 provides a description of how to use DMA with TIM1 Update request
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to transfer Data from memory to TIM1 Capture Compare Register 3 (CCR3).
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The following configuration values are used in this example:
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- TIM1CLK = SystemCoreClock
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- Prescaler = 0
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- TIM1 counter clock = SystemCoreClock
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- SystemCoreClock is set to 180 MHz for STM32F4xx
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The objective is to configure TIM1 channel 3 to generate complementary PWM
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(Pulse Width Modulation) signal with a frequency equal to 17.57 KHz, and a variable
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duty cycle that is changed by the DMA after a specific number of Update DMA request.
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The number of this repetitive requests is defined by the TIM1 Repetition counter,
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each (3 +1) Update Requests, the TIM1 Channel 3 Duty Cycle changes to the next new
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value defined by the aSRC_Buffer.
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The PWM waveforms 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, DMA, PWM, Frequency, Duty Cycle, Waveform, Oscilloscope, Output, Signal
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@par Directory contents
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- TIM/TIM_DMA/system_stm32f4xx.c STM32F4xx system clock configuration file
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- TIM/TIM_DMA/stm32f4xx_hal_conf.h HAL configuration file
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- TIM/TIM_DMA/stm32f4xx_it.h Interrupt handlers header file
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- TIM/TIM_DMA/stm32f4xx_it.c Interrupt handlers
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- TIM/TIM_DMA/main.c Main program
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- TIM/TIM_DMA/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 STMicroelectronics STM324x9I-EVAL RevB
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evaluation board and can be easily tailored to any other supported device
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and development board.
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- STM324x9I-EVAL RevB Set-up:
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- Connect the TIM1 pins to an oscilloscope to monitor the different waveforms:
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- TIM1 CH3 (PE.13)
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- TIM1 CH3N (PB.15)
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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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