107 lines
4.7 KiB
Plaintext
107 lines
4.7 KiB
Plaintext
/**
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@page TIM_OCToggle TIM_OCToggle example
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@verbatim
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******************************************************************************
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* @file TIM/TIM_OCToggle/readme.txt
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* @author MCD Application Team
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* @brief This example shows how to configure the Timer to generate four different
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* signals with four different frequencies.
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******************************************************************************
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*
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* Copyright (c) 2020 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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Configuration of the TIM peripheral to generate four different
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signals at four different frequencies.
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At the beginning of the main program the HAL_Init() function is called to reset
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all the peripherals, initialize the Flash interface and the systick.
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The SystemClock_Config() function is used to configure the system clock for STM32WL55JCIx Devices :
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The CPU at 48 MHz
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The TIM1 frequency is set to SystemCoreClock, and the objective is
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to get TIM1 counter clock at 1 MHz so the Prescaler is computed as following:
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- Prescaler = (TIM1CLK /TIM1 counter clock) - 1
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SystemCoreClock is set to 48 MHz for STM32WLxx Devices.
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The TIM1 CCR1 register value is equal to 625:
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CC1 update rate = TIM1 counter clock / CCR1_Val = 1600 Hz,
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so the TIM1 Channel 1 generates a periodic signal with a frequency equal to 800 Hz.
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The TIM1 CCR2 register value is equal to 1250:
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CC2 update rate = TIM1 counter clock / CCR2_Val = 800 Hz,
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so the TIM1 channel 2 generates a periodic signal with a frequency equal to 400 Hz.
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The TIM1 CCR3 register value is equal to 2500:
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CC3 update rate = TIM1 counter clock / CCR3_Val = 400 Hz,
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so the TIM1 channel 3 generates a periodic signal with a frequency equal to 200 Hz.
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The TIM1 CCR4 register value is equal to 5000:
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CC4 update rate = TIM1 counter clock / CCR4_Val = 200 Hz,
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so the TIM1 channel 4 generates a periodic signal with a frequency equal to 100 Hz.
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@note PWM signal frequency values mentioned above are theoretical (obtained when the system clock frequency
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is exactly 48 MHz). Since the generated system clock frequency may vary from one board to another observed
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PWM signal frequency might be slightly different.
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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 This example needs 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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LED3 is ON when there are an error.
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@par Keywords
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Timer, Output, signals, Output compare toggle, PWM, Oscilloscope
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@par Directory contents
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- TIM/TIM_OCToggle/Inc/stm32wlxx_nucleo_conf.h BSP configuration file
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- TIM/TIM_OCToggle/Inc/stm32wlxx_hal_conf.h HAL configuration file
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- TIM/TIM_OCToggle/Inc/stm32wlxx_it.h Interrupt handlers header file
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- TIM/TIM_OCToggle/Inc/main.h Header for main.c module
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- TIM/TIM_OCToggle/Src/stm32wlxx_it.c Interrupt handlers
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- TIM/TIM_OCToggle/Src/main.c Main program
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- TIM/TIM_OCToggle/Src/stm32wlxx_hal_msp.c HAL MSP file
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- TIM/TIM_OCToggle/Src/system_stm32wlxx.c STM32WLxx system source file
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@par Hardware and Software environment
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- This example runs on STM32WL55JCIx devices.
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- This example has been tested with STMicroelectronics NUCLEO-WL55JC RevC
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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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- NUCLEO-WL55JC RevC Set-up
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Connect the following pins to an oscilloscope to monitor the different waveforms:
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- PA8: (TIM1_CH1) (pin 16 in CN10 connector)
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- PA9: (TIM1_CH2) (pin 19 in CN10 connector)
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- PA10: (TIM1_CH3) (pin 32 in CN7 connector)
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- PA11: (TIM1_CH4) (pin 5 in CN10 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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