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 Example9.
********************************************************************************
* 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.
*******************************************************************************/
本例展示了如何在串联模式（cascade mode）下同步多个定时期（TIM）外设。

在本例程中，使用3个定时器，串联模式下同步它们：

1. 设置TIM2为主定时器
 - 使用PWM模式
 - TIM2更新事项作为触发输出

2. 设置TIM3为TIM2的从定时器，为TIM4的主定时器
 - 使用PWM模式
 - 使用ITR1(TIM2)作为这个定时器的触发输入
 - 使用门控模式（Gated mode），从定时器的启动和停止都由主定时器TIM2的触发输出信号（Master trigger output signal）控制。
 - TIM3更新事项作为触发输出

3. 设置TIM4为TIM3的从定时器
 - 使用PWM模式
 - 使用ITR2(TIM3)作为这个定时器的触发输入
 - 使用门控模式（Gated mode），从定时器的启动和停止都由主定时器TIM3的触发输出信号（Master trigger output signal）控制。

TIMxCLK固定为72 MHz，TIM2计数器时钟为72 MHz。

主定时器TIM2输出频率为TIM2频率（TIM2 frequency），
TIM2 frequency = TIM2 counter clock/ (TIM2 period + 1) = 281.250 KHz；
占空比为TIM2_CCR1/(TIM2_ARR + 1) = 25%的信号。

TIM3输出频率为 (TIM2 frequency)/ (TIM3 period + 1) = 70.312 KHz；
占空比为TIM3_CCR1/(TIM3_ARR + 1) = 25%的信号。

TIM4输出频率为  (TIM3 frequency)/ (TIM4 period + 1) = 17.578 Hz；
占空比为TIM4_CCR1/(TIM4_ARR + 1) = 25%的信号。

Example description
===================

This example shows how to synchronize TIM peripherals in cascade mode.
In this example three timers are used:

Timers synchronisation in cascade mode:
1/TIM2 is configured as Master Timer:
 - PWM Mode is used
 - The TIM2 Update event is used as Trigger Output  

2/TIM3 is slave for TIM2 and Master for TIM4,
 - PWM Mode is used
 - The ITR1(TIM2) is used as input trigger 
 - Gated mode is used, so start and stop of slave counter
	  are controlled by the Master trigger output signal(TIM2 update event).
 - The TIM3 Update event is used as Trigger Output. 

3/TIM4 is slave for TIM3,
 - PWM Mode is used
 - The ITR2(TIM3) is used as input trigger
 - Gated mode is used, so start and stop of slave counter  are controlled by the
   Master trigger output signal(TIM3 update event).

The TIMxCLK is fixed to 72 MHz, the TIM2 counter clock is 72 MHz.
The Master Timer TIM2 is running at TIM2 frequency :
TIM2 frequency = (TIM2 counter clock)/ (TIM2 period + 1) = 281.250 KHz 
and the duty cycle = TIM2_CCR1/(TIM2_ARR + 1) = 25%.

The TIM3 is running:
 - At (TIM2 frequency)/ (TIM3 period + 1) = 70.312 KHz and a duty cycle equal 
to TIM3_CCR1/(TIM3_ARR + 1) = 25%

The TIM4 is running:
 - At (TIM3 frequency)/ (TIM4 period + 1) = 17.578 Hz and a duty cycle equal 
to TIM4_CCR1/(TIM4_ARR + 1) = 25%
  

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 
- TIM2 CH1 (PA.00) 
- TIM3 CH1 (PA.06)
- TIM4 CH1 (PB.06) 
pins to an oscilloscope to show the waveforms.
   
  
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******