stm32f103,pwm输出使用PWM1模式和PWM2模式的示波器显示

wangsongboke@16

两种模式下PWM1模式输出电压相对与PWM2模式稳定一些（用示波器查看），不知道在实际对舵机的控制中影响如何。下面是源码：
int main(void)
 {
  u16 led0pwmval=0;
u8 dir=1;
delay_init();     //???±??????????  
NVIC_Configuration(); //?è??NVIC????·?×é2:2??????????????2???ì????????
uart_init(9600); //?®??????????9600
  LED_Init();     //LED??????????
  TIM3_PWM_Init(4000,36); //??·?????PWM????=72000000/900=80Khz
TIM_SetCompare2(TIM3,2000);
    while(1)
{
  //delay_ms(10);  
if(dir)
{
led0pwmval=led0pwmval+100;
}
else 
{
     led0pwmval=led0pwmval-100;
    }

  if(3000+led0pwmval>4000)dir=0;
{
//TIM_SetCompare2(TIM3,3000);
}
if(2000+led0pwmval==2000)dir=1;
{
//TIM_SetCompare2(TIM3,2000);
}
   
           
    LED0=!LED0;
    LED1=!LED1;
delay_ms(100);
TIM_SetCompare2(TIM3,2000+led0pwmval);
delay_ms(10000);
}  
 }
pwm 初始化
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); //?????¨?±?÷3?±??
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC  | RCC_APB2Periph_AFIO, ENABLE);  //????GPIO???è??AFIO???????????é?±??

GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE); //Timer3??·???????  TIM3_CH2->B5    
 
   //?è??????????????????????,????TIM3 CH2??PWM?????¨?? GPIOB.5
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //???????ì????
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOC, &GPIO_InitStructure);//??????GPIO
 
   //??????TIM3
TIM_TimeBaseStructure.TIM_Period = arr; //?è???????????ü??????×°????????×?????×°???????÷????????
TIM_TimeBaseStructure.TIM_Prescaler =psc; //?è??????×÷??TIMx?±?????????????¤·????? 
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //?è???±??·???:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM?ò??????????
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //?ù??TIM_TimeBaseInitStruct?????¨????????????TIMx???±???ù??????

//??????TIM3 Channel2 PWM????  
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //?????¨?±?÷????:TIM?????í???÷??????2
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //±???????????
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //????????:TIM????±?????????
TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //?ù??T???¨???????????????èTIM3 OC2

TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //????TIM3??CCR2?????¤×°???????÷
 
TIM_Cmd(TIM3, ENABLE);  //????TIM3


}

正点原子

就是输出电平高低的区别啊。