90 lines
3.6 KiB
Plaintext
90 lines
3.6 KiB
Plaintext
/**
|
|
@page TIM_TimeBase Time Base example
|
|
|
|
@verbatim
|
|
******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
|
|
* @file TIM/TIM_TimeBase/readme.txt
|
|
* @author MCD Application Team
|
|
* @brief Description of the TIM Time Base example
|
|
******************************************************************************
|
|
* @attention
|
|
*
|
|
* Copyright (c) 2016 STMicroelectronics.
|
|
* All rights reserved.
|
|
*
|
|
* This software is licensed under terms that can be found in the LICENSE file
|
|
* in the root directory of this software component.
|
|
* If no LICENSE file comes with this software, it is provided AS-IS.
|
|
*
|
|
******************************************************************************
|
|
@endverbatim
|
|
|
|
@par Example Description
|
|
|
|
Configuration of the TIM peripheral to generate a timebase of
|
|
one second with the corresponding interrupt request.
|
|
|
|
In this example TIM3 input clock (TIM3CLK) is set to APB1 clock (PCLK1) x2,
|
|
since APB1 prescaler is set to 4 (0x100).
|
|
TIM3CLK = PCLK1*2
|
|
PCLK1 = HCLK/2
|
|
=> TIM3CLK = PCLK1*2 = (HCLK/2)*2 = HCLK = SystemCoreClock
|
|
To get TIM3 counter clock at 10 KHz, the Prescaler is computed as following:
|
|
Prescaler = (TIM3CLK / TIM3 counter clock) - 1
|
|
Prescaler = (SystemCoreClock /10 KHz) - 1
|
|
|
|
SystemCoreClock is set to 64 MHz for STM32F1xx Devices.
|
|
|
|
The TIM3 ARR register value is equal to 10000 - 1,
|
|
Update rate = TIM3 counter clock / (Period + 1) = 1 Hz,
|
|
So the TIM3 generates an interrupt each 1 s
|
|
|
|
When the counter value reaches the auto-reload register value, the TIM update
|
|
interrupt is generated and, in the handler routine, pin PA.05 pin (pin 11 in CN10 connector) (connected to LED2 on board STM32F103RB-Nucleo)
|
|
is toggled at the following frequency: 0.5Hz.
|
|
|
|
|
|
@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
|
|
based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
|
|
a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
|
|
than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
|
|
To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
|
|
|
|
@note The application need to ensure that the SysTick time base is always set to 1 millisecond
|
|
to have correct HAL operation.
|
|
|
|
@par Directory contents
|
|
|
|
- TIM/TIM_TimeBase/Inc/stm32f1xx_hal_conf.h HAL configuration file
|
|
- TIM/TIM_TimeBase/Inc/stm32f1xx_it.h Interrupt handlers header file
|
|
- TIM/TIM_TimeBase/Inc/main.h Header for main.c module
|
|
- TIM/TIM_TimeBase/Src/stm32f1xx_it.c Interrupt handlers
|
|
- TIM/TIM_TimeBase/Src/main.c Main program
|
|
- TIM/TIM_TimeBase/Src/stm32f1xx_hal_msp.c HAL MSP file
|
|
- TIM/TIM_TimeBase/Src/system_stm32f1xx.c STM32F1xx system source file
|
|
|
|
|
|
@par Hardware and Software environment
|
|
|
|
- This example runs on STM32F103RB devices.
|
|
- In this example, the clock is set to 64 MHz.
|
|
|
|
- This example has been tested with STMicroelectronics STM32F103RB-Nucleo
|
|
board and can be easily tailored to any other supported device
|
|
and development board.
|
|
|
|
- STM32F103RB-Nucleo Set-up
|
|
- Use LED2 connected to PA.05 pin (pin 11 in CN10 connector) pin and connect them on an oscilloscope
|
|
to show the Time Base signal.
|
|
|
|
|
|
@par How to use it ?
|
|
|
|
In order to make the program work, you must do the following :
|
|
- Open your preferred toolchain
|
|
- Rebuild all files and load your image into target memory
|
|
- Run the example
|
|
|
|
|
|
*/
|