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112 lines
4.7 KiB
Plaintext
112 lines
4.7 KiB
Plaintext
/**
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@page TIM_ExtTriggerSynchro TIM External Trigger Synchro example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file TIM/TIM_ExtTriggerSynchro/readme.txt
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* @author MCD Application Team
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* @brief Description of the TIM External Trigger Synchro example.
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******************************************************************************
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*
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* Copyright (c) 2017 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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This example shows how to synchronize TIM peripherals in cascade mode with an
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external trigger.
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In this example three timers are used:
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1/TIM1 is configured as Master Timer:
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- Toggle Mode is used
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- The TIM1 Enable event is used as Trigger Output
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2/TIM1 is configured as Slave Timer for an external Trigger connected to TIM1
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TI2 pin (TIM1 CH2 configured as input pin):
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- The TIM1 TI2FP2 is used as Trigger Input
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- Rising edge is used to start and stop the TIM1: Gated Mode.
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3/TIM4 is slave for TIM1 and Master for TIM5,
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- Toggle Mode is used
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- The ITR0 (TIM1) is used as input trigger
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- Gated mode is used, so start and stop of slave counter
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are controlled by the Master trigger output signal(TIM1 enable event).
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- The TIM4 enable event is used as Trigger Output.
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4/TIM5 is slave for TIM4,
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- Toggle Mode is used
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- The ITR2 (TIM4) is used as input trigger
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- Gated mode is used, so start and stop of slave counter
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are controlled by the Master trigger output signal(TIM4 enable event).
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The TIM1CLK is set to SystemCoreClock,
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TIM4CLK is set to (SystemCoreClock/2) and
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TIM5CLK frequency is set to (SystemCoreClock/2),
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to get TIMx counter clock at 18 MHz the Prescaler is computed as following:
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- Prescaler = (TIMx CLK / TIMx counter clock) - 1
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SystemCoreClock is set to 180 MHz.
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TIMx frequency = TIMx counter clock/ 2*(TIMx_Period + 1) = 100 KHz.
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The starts and stops of the TIM1 counters are controlled by the external trigger.
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The TIM4 starts and stops are controlled by the TIM1, and the TIM5 starts and
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stops are controlled by the TIM4.
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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 The application need 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, PWM, External Trigger, Synchronization, Cascade mode, Master, Slave, Duty Cycle, Waveform,
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Oscilloscope, Output, Signal
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@par Directory contents
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- TIM/TIM_ExtTriggerSynchro/Inc/stm32f4xx_hal_conf.h HAL configuration file
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- TIM/TIM_ExtTriggerSynchro/Inc/stm32f4xx_it.h Interrupt handlers header file
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- TIM/TIM_ExtTriggerSynchro/Inc/main.h Header for main.c module
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- TIM/TIM_ExtTriggerSynchro/Src/stm32f4xx_it.c Interrupt handlers
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- TIM/TIM_ExtTriggerSynchro/Src/main.c Main program
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- TIM/TIM_ExtTriggerSynchro/Src/stm32f4xx_hal_msp.c HAL MSP file
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- TIM/TIM_ExtTriggerSynchro/Src/system_stm32f4xx.c STM32F4xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F446xx devices.
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- This example has been tested with STMicroelectronics STM32446E-EVAL
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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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- STM32446E-EVAL Set-up
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- Connect an external trigger to the TIM1 CH2 PA.09 (pin 11 in CN10 connector).
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- Connect the following pins to an oscilloscope to monitor the different waveforms:
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- TIM1 CH1 PA.08 (pin 1 in CN6 connector)
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- TIM4 CH3 PB.08 (pin 16 in CN10 connector)
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- TIM5 CH1 PA.00 (pin 27 in CN13 connector)
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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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