/**
@page TIM_OCToggle TIM_OCToggle example
@verbatim
******************************************************************************
* @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.
******************************************************************************
*
* Copyright (c) 2020 STMicroelectronics. All rights reserved.
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
@endverbatim
@par Example Description
Configuration of the TIM peripheral to generate four different
signals at four different frequencies.
At the beginning of the main program the HAL_Init() function is called to reset
all the peripherals, initialize the Flash interface and the systick.
The SystemClock_Config() function is used to configure the system clock for STM32WL55JCIx Devices :
The CPU at 48 MHz
The TIM1 frequency is set to SystemCoreClock, and the objective is
to get TIM1 counter clock at 1 MHz so the Prescaler is computed as following:
- Prescaler = (TIM1CLK /TIM1 counter clock) - 1
SystemCoreClock is set to 48 MHz for STM32WLxx Devices.
The TIM1 CCR1 register value is equal to 625:
CC1 update rate = TIM1 counter clock / CCR1_Val = 1600 Hz,
so the TIM1 Channel 1 generates a periodic signal with a frequency equal to 800 Hz.
The TIM1 CCR2 register value is equal to 1250:
CC2 update rate = TIM1 counter clock / CCR2_Val = 800 Hz,
so the TIM1 channel 2 generates a periodic signal with a frequency equal to 400 Hz.
The TIM1 CCR3 register value is equal to 2500:
CC3 update rate = TIM1 counter clock / CCR3_Val = 400 Hz,
so the TIM1 channel 3 generates a periodic signal with a frequency equal to 200 Hz.
The TIM1 CCR4 register value is equal to 5000:
CC4 update rate = TIM1 counter clock / CCR4_Val = 200 Hz,
so the TIM1 channel 4 generates a periodic signal with a frequency equal to 100 Hz.
@note PWM signal frequency values mentioned above are theoretical (obtained when the system clock frequency
is exactly 48 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 This example needs to ensure that the SysTick time base is always set to 1 millisecond
to have correct HAL operation.
LED3 is ON when there are an error.
@par Keywords
Timer, Output, signals, Output compare toggle, PWM, Oscilloscope
@par Directory contents
- TIM/TIM_OCToggle/Inc/stm32wlxx_nucleo_conf.h BSP configuration file
- TIM/TIM_OCToggle/Inc/stm32wlxx_hal_conf.h HAL configuration file
- TIM/TIM_OCToggle/Inc/stm32wlxx_it.h Interrupt handlers header file
- TIM/TIM_OCToggle/Inc/main.h Header for main.c module
- TIM/TIM_OCToggle/Src/stm32wlxx_it.c Interrupt handlers
- TIM/TIM_OCToggle/Src/main.c Main program
- TIM/TIM_OCToggle/Src/stm32wlxx_hal_msp.c HAL MSP file
- TIM/TIM_OCToggle/Src/system_stm32wlxx.c STM32WLxx system source file
@par Hardware and Software environment
- This example runs on STM32WL55JCIx devices.
- This example has been tested with STMicroelectronics NUCLEO-WL55JC RevC
board and can be easily tailored to any other supported device
and development board.
- NUCLEO-WL55JC RevC Set-up
Connect the following pins to an oscilloscope to monitor the different waveforms:
- PA8: (TIM1_CH1) (pin 16 in CN10 connector)
- PA9: (TIM1_CH2) (pin 19 in CN10 connector)
- PA10: (TIM1_CH3) (pin 32 in CN7 connector)
- PA11: (TIM1_CH4) (pin 5 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
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
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