92 lines
3.7 KiB
Plaintext
92 lines
3.7 KiB
Plaintext
/**
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@page TIM_TimeBase Time Base example
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@verbatim
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******************** (C) COPYRIGHT 2016 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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* @attention
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*
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* <h2><center>© Copyright (c) 2016 STMicroelectronics.
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* All rights reserved.</center></h2>
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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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Configuration of the TIM peripheral to generate a timebase 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 APB1 clock (PCLK1) x2,
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since APB1 prescaler is set to 4 (0x100).
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TIM3CLK = PCLK1*2
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PCLK1 = HCLK/2
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=> TIM3CLK = PCLK1*2 = (HCLK/2)*2 = HCLK = SystemCoreClock
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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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Prescaler = (SystemCoreClock /10 KHz) - 1
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SystemCoreClock is set to 72 MHz for STM32F1xx 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 update
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interrupt is generated and, in the handler routine, pin PF.08 (connected to LED3 on board STM3210E-EVAL RevD)
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is toggled at the following frequency: 0.5Hz.
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In case of error, LED4 is turned ON.
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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 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 Directory contents
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- TIM/TIM_TimeBase/Inc/stm32f1xx_hal_conf.h HAL configuration file
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- TIM/TIM_TimeBase/Inc/stm32f1xx_it.h Interrupt handlers header file
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- TIM/TIM_TimeBase/Inc/main.h Header for main.c module
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- TIM/TIM_TimeBase/Src/stm32f1xx_it.c Interrupt handlers
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- TIM/TIM_TimeBase/Src/main.c Main program
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- TIM/TIM_TimeBase/Src/stm32f1xx_hal_msp.c HAL MSP file
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- TIM/TIM_TimeBase/Src/system_stm32f1xx.c STM32F1xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F103xG devices.
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- In this example, the clock is set to 72 MHz.
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- This example has been tested with STMicroelectronics STM3210E-EVAL RevD
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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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- STM3210E-EVAL RevD Set-up
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- Use LED3 connected to PF.08 pin and connect them on an oscilloscope
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to show the Time Base signal.
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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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