如题。现在用TIM4的通道2输入PWM，上升沿捕获。在几千赫兹时测得脉冲数还算准确，在更低的时候就不行了。比如100hz时，测了1s,脉冲数为0。请问香版主这是咋回事？是我stm32哪里配置不对吗？
void TIM4_Configuration(void) //只用一个外部脉冲端口
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
//配置TIMER1作为计数器
TIM4_Config();
TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM_TimeBaseStructure.TIM_Prescaler = 0x00;
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); // Time base configuration
//TIM_ETRClockMode2Config(TIM4, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 0);
TIM_TIxExternalClockConfig(TIM4,TIM_TIxExternalCLK1Source_TI2,TIM_ICPolarity_Rising,0);
/* Enable TIM2 Update interrupt [TIM2溢出中断允许]*/
TIM_ITConfig(TIM4, TIM_IT_Update, ENABLE);
TIM_SetCounter(TIM4, 0);
TIM_Cmd(TIM4, ENABLE);
}
void TIM4_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
/* TIM4 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
/* GPIOB clock enable */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
/* TIM4 chennel2 configuration : PB.07 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
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(GPIOB, &GPIO_InitStructure);
/* Connect TIM pin to AF2 */
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_TIM4);
/* Enable the TIM4 global Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
} |
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