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/**
@page TIM_OCActive TIM_OCActive example
@verbatim
******************************************************************************
* @file TIM/TIM_OCActive/readme.txt
* @author MCD Application Team
* @brief This example shows how to configure the Timer to generate four
* delayed signals.
******************************************************************************
*
* Copyright (c) 2019 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 in Output Compare Active mode
(when the counter matches the capture/compare register, the corresponding output
pin is set to its active state).
The TIM2 frequency is set to SystemCoreClock, and the objective is
to get TIM2 counter clock at 10 kHz so the Prescaler is computed as following:
- Prescaler = (TIM2CLK /TIM2 counter clock) - 1
SystemCoreClock is set to 64 MHz for STM32WBxx Devices.
The TIM2 CCR1 register value is equal to 10000:
TIM2_CH1 delay = CCR1_Val/TIM2 counter clock = 1s
so the TIM2 Channel 1 generates a signal with a delay equal to 1s.
The TIM2 CCR2 register value is equal to 5000:
TIM2_CH2 delay = CCR2_Val/TIM2 counter clock = 500 ms
so the TIM2 Channel 2 generates a signal with a delay equal to 500 ms.
The TIM2 CCR3 register value is equal to 2500:
TIM2_CH3 delay = CCR3_Val/TIM2 counter clock = 250 ms
so the TIM2 Channel 3 generates a signal with a delay equal to 250 ms.
The TIM2 CCR4 register value is equal to 1250:
TIM2_CH4 delay = CCR4_Val/TIM2 counter clock = 125 ms
so the TIM2 Channel 4 generates a signal with a delay equal to 125 ms.
The delay correspond to the time difference between PB0 rising edge and
TIM2_CHx signal rising edges.
STM32 board LED can be used to monitor the example status:
- LED2 turns ON if example is OK.
- LED3 toggles slowly in case of error.
@note Delay values mentioned above are theoretical (obtained when the system clock frequency
is exactly 64 MHz). Since the generated system clock frequency may vary from one board to another observed
delay 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.
@par Keywords
Timer, Output, Compare, Active, Signals,
@par Directory contents
- TIM/TIM_OCActive/Inc/stm32wbxx_hal_conf.h HAL configuration file
- TIM/TIM_OCActive/Inc/stm32wbxx_it.h Interrupt handlers header file
- TIM/TIM_OCActive/Inc/main.h Header for main.c module
- TIM/TIM_OCActive/Src/stm32wbxx_it.c Interrupt handlers
- TIM/TIM_OCActive/Src/main.c Main program
- TIM/TIM_OCActive/Src/stm32wbxx_hal_msp.c HAL MSP file
- TIM/TIM_OCActive/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB55xx devices.
- This example has been tested with STMicroelectronics P-NUCLEO-WB55
board and can be easily tailored to any other supported device
and development board.
- P-NUCLEO-WB55 Set-up
Connect the following pins to an oscilloscope to monitor the different waveforms:
- Use LED2 connected to PB0 (Reference) (pin 22 in CN10 connector)
- PA0: (TIM2_CH1) (pin 34 in CN7 connector)
- PA1: (TIM2_CH2) (pin 32 in CN7 connector)
- PA2: (TIM2_CH3) (pin 35 in CN10 connector)
- PA3: (TIM2_CH4) (pin 37 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
You should see these waveforms on oscilloscope :
CH1 ________________
_______________________________________________________________|
<---------------------- 1sec------------------------->
CH2 __________________________________________
______________________________________|
<------------500ms--------->
CH3 _____________________________________________________
___________________________|
<----250ms------->
CH4 ____________________________________________________________
_____________________|
<--125ms--->
LED ______________________________________________________________________
__________|
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
|
