紧急求助，我用Timer5设定采样时间（10ms），用Timer2捕获电机的转速，并用串口打印到上位机上，结果不准确！！

Bois1993

void TIM5_Int_Init(u16 arr,u16 psc)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);


TIM_TimeBaseStructure.TIM_Period = arr; 
TIM_TimeBaseStructure.TIM_Prescaler =psc; 
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; 
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  
TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure); 
 
TIM_ITConfig(TIM5,TIM_IT_Update,ENABLE ); 


NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn;  
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;  
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 
NVIC_Init(&NVIC_InitStructure); 


TIM_Cmd(TIM5, ENABLE);    
}
void TIM2_Mode_Config(void)
{
   GPIO_InitTypeDef GPIO_InitStructure; //定义一个GPIO结构体变量
   TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;//定义一个定时器结构体变量
   TIM_ICInitTypeDef TIM_ICInitStructure; //定义一个定时器编码器结构体变量
  
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//使能GPIOA时钟
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);//使能定时器2
  
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1; //配置PA0->TIM2_CH1,PA1->TIM2_CH2
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //设置50MHz时钟
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD; //设置为下拉输入模式
   GPIO_Init(GPIOA, &GPIO_InitStructure);

   TIM_TimeBaseStructure.TIM_Period = 0xffff; //计数器最大值
   TIM_TimeBaseStructure.TIM_Prescaler = 0; //时钟不分频
   TIM_TimeBaseStructure.TIM_ClockDivision = 0; // 使用的采样频率之间的分频比例
   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数
   TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //初始化定时器2

   TIM_EncoderInterfaceConfig(TIM2, TIM_EncoderMode_TI12,TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
   TIM_ICStructInit(&TIM_ICInitStructure);
   TIM_ICInitStructure.TIM_ICFilter = 6;
   TIM_ICInit(TIM2, &TIM_ICInitStructure);
  
TIM_SetCounter(TIM2, 0);

  TIM_ClearFlag(TIM2, TIM_FLAG_Update);

  TIM_Cmd(TIM2, ENABLE);  //计数器使能，开始计数
}

u16 Get_Speed(void)
{
u16 speed;
speed = TIM_GetCounter(TIM2);
TIM_SetCounter(TIM2, 0);

return speed;
}

 void TIM5_IRQHandler(void)
{
if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)  //检查TIM5更新中断发生与否
{
  TIM_ClearITPendingBit(TIM5,  TIM_IT_Update); 
  
  if ( 0==flag )
{ 
     flag=1;  
   }
   } 
}

u8 flag;
 int main(void)
 {
  flag = 0;
delay_init();     //延时函数初始化  
NVIC_Configuration(); //设置NVIC中断分组2:2位抢占优先级，2位响应优先级
uart_init(9600); //串口初始化为9600
TIM2_Mode_Config();
TIM5_Int_Init(9999,71);
while(1)
{
if(flag == 1)
{
printf("%d   ",Get_Speed());
flag = 0;
}
    }
 }

Bois1993

这是捕获的速度，明显不对

Bois1993

求助啊！！！