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/******************** (C) COPYRIGHT 2008 STMicroelectronics ********************
* File Name : readme.txt
* Author : MCD Application Team
* Version : V2.0.1
* Date : 06/13/2008
* Description : Description of the TIM PWM_Output 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 DIRECT,
* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING 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 configure the TIM peripheral in PWM (Pulse Width Modulation)
mode.
The TIMxCLK frequency is set to 36 MHz, the Prescaler is 0 so the TIM3 counter clock is
36 MHz.
The TIM3 is running at 36 KHz: TIM3 Frequency = TIM3 counter clock/(ARR + 1)
The TIM3 CCR1 register value is equal to 500, so the TIM3 Channel 1 generates a
PWM signal with a frequency equal to 36 KHz and a duty cycle equal to 50%:
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR + 1)* 100 = 50%
The TIM3 CCR2 register value is equal to 375, so the TIM3 Channel 2 generates a
PWM signal with a frequency equal to 36 KHz and a duty cycle equal to 37.5%:
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR + 1)* 100 = 37.5%
The TIM3 CCR3 register value is equal to 250, so the TIM3 Channel 3 generates a
PWM signal with a frequency equal to 36 KHz and a duty cycle equal to 25%:
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR + 1)* 100 = 25%
The TIM3 CCR4 register value is equal to 125, so the TIM3 Channel 4 generates a
PWM signal with a frequency equal to 36 KHz and a duty cycle equal to 12.5%:
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR + 1)* 100 = 12.5%
The PWM waveform can be displayed using an oscilloscope.
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
====================
This example runs on STMicroelectronics STM3210B-EVAL and STM3210E-EVAL evaluation
boards and can be easily tailored to any other hardware.
There is no need for any modification when switching between these two boards.
Connect the:
- PA.06: (TIM3_CH1)
- PA.07: (TIM3_CH2)
- PB.00: (TIM3_CH3)
- PB.01: (TIM3_CH4)
pins to an oscilloscope to monitor the different 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 target memory
- Run the example
******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE******
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