/**
@page TIM_OCToggle TIM_OCToggle example
@verbatim
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
* @file TIM/TIM_OCToggle/readme.txt
* @author MCD Application Team
* @brief This example shows how to configure the Timer to generate four different
* signals with four different frequencies.
******************************************************************************
* @attention
*
* Copyright (c) 2017 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
This example shows how to configure the TIM peripheral to generate four different
signals with four different frequencies.
The TIM3 frequency is set to SystemCoreClock, and the objective is
to get TIM3 counter clock at 12.5 MHz so the Prescaler is computed as following:
- Prescaler = (TIM3CLK /TIM3 counter clock) - 1
SystemCoreClock is set to 100 MHz for STM32F413xx/STM32F423xx Devices.
The TIM3 CCR1 register value is equal to 32051:
CC1 update rate = TIM3 counter clock / CCR1_Val = 390 Hz,
so the TIM3 Channel 1 generates a periodic signal with a frequency equal to 195 Hz.
The TIM3 CCR2 register value is equal to 16025:
CC2 update rate = TIM3 counter clock / CCR2_Val = 780 Hz,
so the TIM3 channel 2 generates a periodic signal with a frequency equal to 390 Hz.
The TIM3 CCR3 register value is equal to 8012:
CC3 update rate = TIM3 counter clock / CCR3_Val = 1560 Hz,
so the TIM3 channel 3 generates a periodic signal with a frequency equal to 780 Hz.
The TIM3 CCR4 register value is equal to 4006:
CC4 update rate = TIM3 counter clock / CCR4_Val = 3120 Hz,
so the TIM3 channel 4 generates a periodic signal with a frequency equal to 1560 Hz.
@note PWM signal frequency values mentioned above are theoretical (obtained when the system clock frequency
is exactly 100 MHz). Since the generated system clock frequency may vary from one board to another observed
PWM signal frequency might be slightly different.
@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 Keywords
Timers, Output, signals, Output compare toggle, PWM, Oscilloscope
@par Directory contents
- TIM/TIM_OCToggle/Inc/stm32f4xx_hal_conf.h HAL configuration file
- TIM/TIM_OCToggle/Inc/stm32f4xx_it.h Interrupt handlers header file
- TIM/TIM_OCToggle/Inc/main.h Header for main.c module
- TIM/TIM_OCToggle/Src/stm32f4xx_it.c Interrupt handlers
- TIM/TIM_OCToggle/Src/main.c Main program
- TIM/TIM_OCToggle/Src/stm32f4xx_hal_msp.c HAL MSP file
- TIM/TIM_OCToggle/Src/system_stm32f4xx.c STM32F4xx system source file
@par Hardware and Software environment
- This example runs on STM32F413xx/STM32F423xx devices.
- This example has been tested with STMicroelectronics STM32F413ZH-Nucleo
board and can be easily tailored to any other supported device
and development board.
- STM32F413ZH-Nucleo Set-up
Connect the following pins to an oscilloscope to monitor the different waveforms:
- PB.04: (TIM3_CH1) (connected to PB.04 (pin 19 in CN7 connector))
- PB.05: (TIM3_CH2) (connected to PB.05 (pin 13 in CN7 connector))
- PB.00: (TIM3_CH3) (connected to PB.00 (pin 31 in CN10 connector))
- PB.01: (TIM3_CH4) (connected to PB.01 (pin 7 in CN10 connector))
@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
*/
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