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diff --git a/Projects/NUCLEO-WB35CE/Examples_MIX/TIM/TIM_PWMInput/readme.txt b/Projects/NUCLEO-WB35CE/Examples_MIX/TIM/TIM_PWMInput/readme.txt new file mode 100644 index 000000000..062b19569 --- /dev/null +++ b/Projects/NUCLEO-WB35CE/Examples_MIX/TIM/TIM_PWMInput/readme.txt @@ -0,0 +1,92 @@ +/** + @page TIM_PWMInput TIM PWM Input example + + @verbatim + ****************************************************************************** + * @file TIM/TIM_PWMInput/readme.txt + * @author MCD Application Team + * @brief Description of the TIM PWM_Input example. + ****************************************************************************** + * + * 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 + +Use of the TIM peripheral to measure an external signal frequency and +duty cycle. + +The TIM2CLK frequency is set to SystemCoreClock/1 (Hz), the Prescaler is 0 so the +counter clock is SystemCoreClock/1 (Hz). + +TIM2 is configured in PWM Input Mode: the external signal is connected to +TIM2 Channel2 used as input pin. +To measure the frequency and the duty cycle, we use the TIM2 CC2 interrupt request, +so in the TIM2_IRQHandler routine, the frequency and the duty cycle of the external +signal are computed. + +"uwFrequency" variable contains the external signal frequency: +TIM2 counter clock = SystemCoreClock/1, +uwFrequency = TIM2 counter clock / TIM2_CCR2 in Hz, + +"uwDutyCycle" variable contains the external signal duty cycle: +uwDutyCycle = (TIM2_CCR1*100)/(TIM2_CCR2) in %. + +The minimum frequency value to measure is (TIM2 counter clock / CCR MAX) + = (64 MHz/1)/ 65535 + = 915,5 Hz + +TIM1 can be used to generate the external signal in case a function generator +is not available. TIM1 is configured in PWM Output Mode to produce a square wave on PA8. +Frequency and duty cycles can be changed by pressing the User Button (PC13). +Six combinations are available (see tables aFrequency[] and aDutyCycle[]). + +@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_PWMInput/Inc/stm32wbxx_hal_conf.h HAL configuration file + - TIM/TIM_PWMInput/Inc/stm32wbxx_it.h Interrupt handlers header file + - TIM/TIM_PWMInput/Inc/main.h Header for main.c module + - TIM/TIM_PWMInput/Src/stm32wbxx_it.c Interrupt handlers + - TIM/TIM_PWMInput/Src/main.c Main program + - TIM/TIM_PWMInput/Src/stm32wbxx_hal_msp.c HAL MSP file + - TIM/TIM_PWMInput/Src/system_stm32wbxx.c STM32WBxx system source file + + +@par Hardware and Software environment + + - This example runs on STM32WB35CEUx devices. + + - This example has been tested with STMicroelectronics NUCLEO-WB35CE + board and can be easily tailored to any other supported device + and development board. + + - NUCLEO-WB35CE Set-up + - You can either Connect the external signal to measure to the TIM2 CH2 pin (PA1) (pin 32 in CN7 connector). + - Or connect TIM1 CH1 pin PA8 (pin 25 in CN10 connector) to the TIM2 CH2 pin (PA1) instead of an external 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 + + * <h3><center>© COPYRIGHT STMicroelectronics</center></h3> + */ |