TIM_PWM_Input

  ******************** (C) COPYRIGHT 2010 STMicroelectronics *******************
  * @file    TIM/PWM_Input/readme.txt 
  * @author  MCD Application Team
  * @version V3.4.0
  * @date    10/15/2010
  * @brief   Description of the TIM PWM_Input example.
  ******************************************************************************
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
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  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  ******************************************************************************
   
Example Description

This example shows how to use the TIM peripheral to measure the frequency and duty cycle of an external signal.

The TIMxCLK frequency is set to SystemCoreClock (Hz), the Prescaler is 0 so the TIM3 counter clock is SystemCoreClock (Hz). SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density and Connectivity line devices. For Low-Density Value line, Medium-Density Value line and High-Density devices, SystemCoreClock is set to 24 MHz.

TIM3 is configured in PWM Input Mode: the external signal is connected to TIM3 Channel2 used as input pin. To measure the frequency and the duty cycle we use the TIM3 CC2 interrupt request, so In the TIM3_IRQHandler routine, the frequency and the duty cycle of the external signal are computed. The "Frequency" variable contains the external signal frequency: Frequency = TIM3 counter clock / TIM3_CCR2 in Hz, The "DutyCycle" variable contains the external signal duty cycle: DutyCycle = (TIM3_CCR1*100)/(TIM3_CCR2) in %.

For Low-density, Medium-density, High-density and Connectivity line devices, the minimum frequency value to measure is 1100 Hz. For Low-Density Value line and Medium-Density Value line devices, the minimum frequency value to measure is 366 Hz.

Directory contents
Hardware and Software environment
How to use it ?

In order to make the program work, you must do the following:

Tip: You can tailor the provided project template to run this example, for more details please refer to "stm32f10x_stdperiph_lib_um.chm" user manual; select "Peripheral Examples" then follow the instructions provided in "How to proceed" section.

Note:
  • Low-density Value line devices are STM32F100xx microcontrollers where the Flash memory density ranges between 16 and 32 Kbytes.
  • Low-density devices are STM32F101xx, STM32F102xx and STM32F103xx microcontrollers where the Flash memory density ranges between 16 and 32 Kbytes.
  • Medium-density Value line devices are STM32F100xx microcontrollers where the Flash memory density ranges between 64 and 128 Kbytes.
  • Medium-density devices are STM32F101xx, STM32F102xx and STM32F103xx microcontrollers where the Flash memory density ranges between 64 and 128 Kbytes.
  • High-density Value line devices are STM32F100xx microcontrollers where the Flash memory density ranges between 256 and 512 Kbytes.
  • High-density devices are STM32F101xx and STM32F103xx microcontrollers where the Flash memory density ranges between 256 and 512 Kbytes.
  • XL-density devices are STM32F101xx and STM32F103xx microcontrollers where the Flash memory density ranges between 512 and 1024 Kbytes.
  • Connectivity line devices are STM32F105xx and STM32F107xx microcontrollers.

© COPYRIGHT 2010 STMicroelectronics

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