设计一个脉冲计数器，脉冲从外部输入给STM32，我的实现方法是利用通用定时器的输入捕获模式，设置上升沿触发中断，然后每进一次中断计数值加一；
但是就是在初始化定时器的时候有些疑问，感觉利用捕获模式时，定时器的分频值和重装计数器的值可以设置为任意值，因为并不需要定时器更新中断，只需要打开输入捕获中断就可以，
可以这样设置吗？@fire @flyleaf @cancore
static void NVIC_TIM3_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
static void TIM3_GPIO_Config(void)
{
//初始化TIM3_CH2引脚,即GPIOA的Pin_7
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
static void TIM3_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_ICInitTypeDef TIM_ICInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
TIM_TimeBaseStructure.TIM_Prescaler = 72-1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period = 1000-1;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //设置上升沿触发
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICFilter = 0;
TIM_ICInit(TIM3, &TIM_ICInitStructure);
TIM_ClearFlag(TIM3, TIM_IT_CC2);
TIM_ITConfig(TIM3, TIM_IT_CC2, ENABLE);
TIM_Cmd(TIM3, ENABLE);
}
void TIM3_Init(void)
{
NVIC_TIM3_Config();
TIM3_GPIO_Config();
TIM3_Mode_Config();
} |
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