STM32L151 PWM输出示例

最近做个项目,需要用PWM控制4线风扇的速度,调试完后顺便将其记录下来.

typedef struct {
	u16 pwm_change_flag;
	u16 pwm_value;
}Pwm_Fan_t;


Pwm_Fan_t Pwm_Fan;

void Pwm_Param_Init(void)
{
	Pwm_Fan.pwm_change_flag=0;
	Pwm_Fan.pwm_value=80;
}


//PD14->TIM4_CH3
void PWM_GPIO_Config(void)  
{ 
  GPIO_InitTypeDef GPIO_InitStructure; 
 
	RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOD, ENABLE);

  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_14; 
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;           // 复用推挽输出 
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; 
  GPIO_Init(GPIOD, &GPIO_InitStructure); 
}


/**************************************************************** 
2017年8月14日14:37:57:cpu的风扇是使用25Khz pwm来调制的
 ***************************************************************/  
void TIM4_Config(u16 pwm)
{  
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;  
	TIM_OCInitTypeDef  TIM_OCInitStructure;  
	/* PWM信号电平跳变值 */     
	u16 CCR3;  

	if(pwm>160-1)
		pwm=160-1;
	
	CCR3=pwm;
	
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);  
	GPIO_PinAFConfig(GPIOD, GPIO_PinSource14, GPIO_AF_TIM4); 										//对于L系列的,这句千万别漏掉了
	
	TIM_Cmd(TIM4, DISABLE);                          
	
	/* Time base configuration */                                            
	TIM_TimeBaseStructure.TIM_Period =160 - 1;//0xEA5F;  
	TIM_TimeBaseStructure.TIM_Prescaler = 8-1;                                  //设置预分频：预分频=2，即为72/3=24MHz  
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;                                //设置时钟分频系数：不分频  
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;                 //向上计数溢出模式  
	TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);  

	/* PWM1 Mode configuration: Channel3 */  
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;                           //配置为PWM模式1  
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;                
	TIM_OCInitStructure.TIM_Pulse = CCR3;                                       //设置跳变值，当计数器计数到这个值时，电平发生跳变  
	TIM_OCInitStructure.TIM_OCPolarity =TIM_OCPolarity_Low;                     //当定时器计数值小于CCR1时为低电平  
	TIM_OC3Init(TIM4, &TIM_OCInitStructure);                                    //使能通道3     
	TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);  
	
	TIM_ARRPreloadConfig(TIM4, ENABLE);                                         //使能TIM4重载寄存器ARR  
	
	/* TIM4 enable counter */  
	TIM_Cmd(TIM4, ENABLE);                                                      //使能TIM4   
}