【求助】STM32捕获频率问题

asdy00000 · 发表于 2012-9-9 12:02:45

芯片：STM32F103RBT6，库：3.4.0，晶振：外部8MHz
下面是主要函数设置

void RCC_cfg()
{ ErrorStatus HSEStartUpStatus;
   RCC_DeInit();
   RCC_HSEConfig(RCC_HSE_ON);
   HSEStartUpStatus = RCC_WaitForHSEStartUp();
if(HSEStartUpStatus == SUCCESS)
{
    RCC_HCLKConfig(RCC_SYSCLK_Div1);
    RCC_PCLK2Config(RCC_HCLK_Div1);
    RCC_PCLK1Config(RCC_HCLK_Div2);
    FLASH_SetLatency(FLASH_Latency_2);
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);
    RCC_PLLCmd(ENABLE);
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET) {}
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
    while(RCC_GetSYSCLKSource() != 0x08) {}
}
}

void TIME2_cfg()
{
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision =0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period =65535;
TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);
TIM_PrescalerConfig(TIM2,0,TIM_PSCReloadMode_Immediate);
  TIM_ICInitStructure.TIM_Channel =TIM_Channel_2;
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM_ICInitStructure.TIM_ICFilter = 0x0;
TIM_ICInit(TIM2, &TIM_ICInitStructure);
TIM_PWMIConfig(TIM2, &TIM_ICInitStructure);
TIM_SelectInputTrigger(TIM2, TIM_TS_TI1FP1);
TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset);
TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);
TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);
TIM_Cmd(TIM2, ENABLE);
}

为什么的捕获的频率最大才是600k啊？捕获1MHz的信号根本不行！
我的设置哪个地方不对啊？！请大侠指点小弟一下！！