STM32F4定时器3应用——PWM输出

只看该作者 · 2013-1-31 16:13

/**
  ******************************************************************************
  * @file bsp.c
  * @author  wangfei
  * @version V1.0.1
  * @date 2012-09-03
  * @brief Initialize board  peripheral
  ******************************************************************************
**/
#include "stm32f4xx.h"
#include "bsp.h"
void Bsp_Init(void)
{
Bsp_GPIO_Config();
Bsp_TIM3_Config();
}
void Bsp_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //Open GPIOD Clock
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC,ENABLE); //Open GPIOC Clock

//config PA8 MCO Output
GPIO_PinAFConfig(GPIOA,GPIO_PinSource8,GPIO_AF_MCO);
  GPIO_InitStructure.GPIO_Pin=GPIO_Pin_8;
  GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType=GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd=GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

//Connect TIM3 Pin to AF2
  GPIO_PinAFConfig(GPIOC,GPIO_PinSource6,GPIO_AF_TIM3);  //TIM3_Ch1
  GPIO_PinAFConfig(GPIOC,GPIO_PinSource7,GPIO_AF_TIM3);  //TIM3_Ch2
  GPIO_PinAFConfig(GPIOC,GPIO_PinSource8,GPIO_AF_TIM3);  //TIM3_Ch3
  GPIO_PinAFConfig(GPIOC,GPIO_PinSource9,GPIO_AF_TIM3);  //TIM3_Ch4
// Config TIM3 Pin
GPIO_InitStructure.GPIO_Pin=(GPIO_Pin_6|GPIO_Pin_7|GPIO_Pin_8|GPIO_Pin_9);
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
GPIO_Init(GPIOC, &GPIO_InitStructure);
}
void Bsp_TIM3_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //Open TIM3  Clock
/*******************************************************************************
TIM3 Config:generate 4 PWM Signals
TIM3CLK(CK_PSC)=2*PCLK1=2*SYSCLK/4=SYSCLK/2=84MHZ

To get TIM3 counter clock at 21 MHz, the prescaler is computed as follows:
TIM3CLK(CK_CNT)=Fclk_psc/(psc[15:0]+1);
psc[15:0]=(Fclk_psc/Fclk_cnt)-1;
prescaler=psc[15:0]=(Fclk_psc/Fclk_cnt)-1=(84/21)-1=3;

To get TIM3 output clock at 30 KHz, the period (ARR)) is computed as follows:
Fout_clk=Fclk_cnt/(ARR+1);
ARR=(Fclk_cnt/Fout_clk)-1=(21000000/30000)-1=699;

TIM3 Channelx duty cycle=(TIM3_CCRx/ TIM3_ARR)*100;
TIM3 Channel1 duty cycle=(TIM3_CCR1/ TIM3_ARR)*100=350/699=50%
TIM3 Channel2 duty cycle=(TIM3_CCR2/ TIM3_ARR)*100=200/699=28.6%
TIM3 Channel3 duty cycle=(TIM3_CCR3/ TIM3_ARR)*100=100/699=14.3%
TIM3 Channel4 duty cycle=(TIM3_CCR4/ TIM3_ARR)*100=500/699=71.5%
********************************************************************************/
TIM_TimeBaseStructure.TIM_Prescaler=3;       //clk_cnt prescale
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //TIM3 Count mode
TIM_TimeBaseStructure.TIM_Period=699;       //Fout_clk=Fclk_cnt/(ARR+1)=21000000/700=30KHZ
TIM_TimeBaseStructure.TIM_ClockDivision=0;

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

/* PWM1 Mode configuration: TIM3_Ch1 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc1 as output
TIM_OCInitStructure.TIM_Pulse=350;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc1 high level avaliable
TIM_OC1Init(TIM3, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc1 preload

/* PWM1 Mode configuration: TIM3_Ch2 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc2 as output
TIM_OCInitStructure.TIM_Pulse=200;                         //config TIM3_CCR2 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc2 high level avaliable
TIM_OC2Init(TIM3, &TIM_OCInitStructure);

TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc2 preload

/* PWM1 Mode configuration: TIM3_CH3 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc3 as output
TIM_OCInitStructure.TIM_Pulse=100;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc3 high level avaliable
TIM_OC3Init(TIM3, &TIM_OCInitStructure);

TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc3 preload

/* PWM1 Mode configuration: TIM3_CH4 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;             //select PWM1 mode
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //config oc4 as output
TIM_OCInitStructure.TIM_Pulse=500;                         //config TIM3_CCR1 vaule
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //config oc4 high level avaliable
TIM_OC4Init(TIM3, &TIM_OCInitStructure);

TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);       // turn on oc4 preload

TIM_ARRPreloadConfig(TIM3, ENABLE);
  /* TIM3 enable counter */
  TIM_Cmd(TIM3, ENABLE);
}