/******************** (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******