void TIM3_PWM_Init(u16 arr,u16 psc)
{  
	GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	

	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);	//使能定时器3时钟
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB  | RCC_APB2Periph_AFIO, ENABLE);  //使能GPIO外设和AFIO复用功能模块时钟
	
	GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射  TIM3_CH2->PB5    
 
   //设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形	GPIOB.5
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //复用推挽输出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIO
 
   //初始化TIM3
	TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
	TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 
	TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
	
	//初始化TIM3 Channel2 PWM模式	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC2

	TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //使能TIM3在CCR2上的预装载寄存器
 
	TIM_Cmd(TIM3, ENABLE);  //使能TIM3
	

}

#include "stm32f4xx.h"



TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
uint16_t CCR1_Val = 333;
uint16_t CCR2_Val = 249;
uint16_t CCR3_Val = 166;
uint16_t CCR4_Val = 83;
uint16_t PrescalerValue = 0;


 void TIM_Config(void);
 void PWM_Config (void);
int main()
{

	TIM_Config();
	PWM_Config();
	while (1)
	{
		
	
	}



}




 void TIM_Config(void)
 {
	GPIO_InitTypeDef GPIO_InitStructure;

   /* TIM3 clock enable */
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
 
   /* GPIOC clock enable */
	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);
  
   /* GPIOC Configuration: TIM3 CH1 (PC6), TIM3 CH2 (PC7), TIM3 CH3 (PC8) and TIM3 CH4 (PC9) */
	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_100MHz;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
	GPIO_Init(GPIOC, &GPIO_InitStructure); 
 
   /* Connect TIM3 pins to AF2 */  
	GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_TIM3);
	GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_TIM3); 
	GPIO_PinAFConfig(GPIOC, GPIO_PinSource8, GPIO_AF_TIM3);
	GPIO_PinAFConfig(GPIOC, GPIO_PinSource9, GPIO_AF_TIM3); 
 }


void PWM_Config (void)
{
	PrescalerValue = (uint16_t) ((SystemCoreClock /2) / 21000000) - 1;
	
	/* Time base configuration */
	TIM_TimeBaseStructure.TIM_Period = 665;
	TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
	
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
	
	/* PWM1 Mode configuration: Channel1 */
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
	
	TIM_OC1Init(TIM3, &TIM_OCInitStructure);
	
	TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
	
	/* PWM1 Mode configuration: Channel2 */
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
	
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);
	
	TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
	
	/* PWM1 Mode configuration: Channel3 */
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
	
	TIM_OC3Init(TIM3, &TIM_OCInitStructure);
	
	TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
	
	/* PWM1 Mode configuration: Channel4 */
	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
	TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
	
	TIM_OC4Init(TIM3, &TIM_OCInitStructure);
	
	TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);
	
	TIM_ARRPreloadConfig(TIM3, ENABLE);
	
	/* TIM3 enable counter */
	TIM_Cmd(TIM3, ENABLE);



}