readme.txt

STM32 的定时器控制实例程序！ 可以直接使用

/******************** (C) COPYRIGHT 2007 STMicroelectronics ********************
* File Name          : readme.txt
* Author             : MCD Application Team
* Version            : V1.0
* Date               : 10/08/2007
* Description        : Description of the TIM Example6.
********************************************************************************
* THE PRESENT SOFTWARE 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 DIRECT,
* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
* CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
*******************************************************************************/
本例展示了如何设置TIM，用它来测量一个外部输入信号的频率和占空比。

TIM2时钟设置为72MHz，预分频设置为0，TIM2计数器时钟可表达为：
TIM2 counter clock = TIMxCLK / (Prescaler +1) = 72 MHz，因此可测量的最小频率值为1100Hz。

设置TIM2工作在PWM输入模式（PWM Input Mode），把外部信号作为输入连接到TIM2通道2。

利用TIM2计数器中断来测量信号的频率和占空比。在TIM2_IRQHandler中，计算信号的频率和占空比，方法如下：

变量"Frequency"为由下式得到的外部信号频率：
Frequency = TIM2 counter clock / TIM2_CCR2  单位Hz
变量"Duty_Cycle"为由下式得到的外部信号占空比：
Duty_Cycle = (TIM2_CCR1*100)/(TIM2_CCR2) 单位%

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 72 MHz, the Prescaler is 0 so the TIM2 counter 
clock is 72 MHz. so the minimum frequency value to measure is 1100 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. 
The "Frequency" variable contains the external signal frequency:
Frequency = TIM2 counter clock / TIM2_CCR2 in Hz, 
The "Duty_Cycle" variable contains the external signal duty cycle:
Duty_Cycle = (TIM2_CCR1*100)/(TIM2_CCR2) in %.


Directory contents
==================
stm32F10x_conf.h  Library Configuration file
stm32F10x_it.c    Interrupt handlers
stm32F10x_it.h    Interrupt handlers header file
main.c            Main program
 

Hardware environment
====================
Connect the external signal to measure to the TIM2 CH2 pin (PA.01)
   
  
How to use it
=============
In order to make the program work, you must do the following:
- Create a project and setup all your toolchain's start-up files
- Compile the directory content files and required Library files:
  + stm32F10x_lib.c
  + stm32F10x_tim.c
  + stm32F10x_gpio.c
  + stm32F10x_rcc.c
  + stm32F10x_nvic.c
  + stm32F10x_flash.c

- Link all compiled files and load your image into either RAM or Flash
- Run the example


******************* (C) COPYRIGHT 2007 STMicroelectronics *****END OF FILE******