下面是我的程序,我要测量输入PWM的频率是50Hz,你看看有什么问题吗?
void tim2_config(void)
{
TIM_DeInit(TIM2);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
TIM_BaseInitStructure.TIM_Period = 65535; //ARR
TIM_BaseInitStructure.TIM_Prescaler = 199; //PSC
TIM_BaseInitStructure.TIM_ClockDivision = 0;
TIM_BaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_BaseInitStructure);
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_PWMIConfig(TIM2, &TIM_ICInitStructure);
TIM_SelectInputTrigger(TIM2, TIM_TS_TI2FP2); /* Select the TIM2 Input Trigger: TI2FP2 */
TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset); //复位模式为从模式
TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable); //使能主从模式
TIM_Cmd(TIM2, ENABLE); //使能TIM2计数器
TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE); //使能CC2中断请求
}
void TIM2_IRQHandler(void)
{
/* Clear TIM2 Capture compare interrupt pending bit */
TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
/* Get the Input Capture value */
IC2Value = TIM_GetCapture2(TIM2);
}
/*******************************************************************************
* Function Name : NVIC_Configuration
* Description : Configures NVIC and Vector Table base location.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void NVIC_Configuration(void)
{
// NVIC_InitTypeDef NVIC_InitStructure;
#ifdef VECT_TAB_RAM
/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else /* VECT_TAB_FLASH */
/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif
/* Configure the NVIC Preemption Priority Bits */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
/* Enable the USART1 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
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