今天帮别人做了一下PWM波的高精度捕获,因为要求精度比较高,所以确定使用双通道的捕获
PWM捕获很多,但是使用双通道的很少,网上大多都是像正点原子一样,使用定时器单通道,捕获到上升沿之后再将定时器设置为下降沿捕获,来获得高电平时间
在要求精度比较高的情况下,可以使用一个定时器,双通道,分别捕获上升沿和下降沿,程序如下
- TIM2使用通道1和通道2 设置为主从模式
- 使用F407
uint32_t Cap_Data1 ;
uint32_t Cap_Data2 ;
float Fre_Cap = 0.0;
float zhouqi_Cap = 0.0;
float Pwm_Duty = 0.0;
TIM_ICInitTypeDef TIM_ICInitStructure;
void Capture_Init(u16 arr, u16 psc)
{
NVIC_InitTypeDef NVIC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //TIM时钟使能
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); //使能PORTA时钟
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度100MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //下拉
GPIO_Init(GPIOA, &GPIO_InitStructure); //初始化
GPIO_PinAFConfig(GPIOA, GPIO_PinSource0 ,GPIO_AF_TIM2); //复用位定时器
TIM_TimeBaseStructure.TIM_Prescaler = psc; //定时器分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseStructure.TIM_Period = arr; //自动重装载值
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //初始化TIM
TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; //选择通道1
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //输入上升沿捕获
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; // 通道方向选择
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //每次检测到捕获输入就触发一次捕获
TIM_ICInitStructure.TIM_ICFilter = 0x0; //
TIM_ICInit(TIM2, &TIM_ICInitStructure);
TIM_ICInitStructure.TIM_Channel = TIM_Channel_2; //选择通道2
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling; //输入上升沿捕获
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_IndirectTI; // 通道方向选择
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //每次检测到捕获输入就触发一次捕获
TIM_ICInitStructure.TIM_ICFilter = 0x0;
TIM_ICInit(TIM2, &TIM_ICInitStructure);
/* Select the TIM2 Input Trigger: TI2FP2 【输入触发源选择】*/
TIM_SelectInputTrigger(TIM2, TIM_TS_TI1FP1); //参考TIM结构图选择滤波后的TI2输入 寄存器SMCR
/* Select the slave Mode: Reset Mode */
TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset); //复位模式-选中的触发输入(TRGI)的上升沿初始化计数器,并且产生一个更新线号
/* Enable the Master/Slave Mode */
TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable); //主从模式选择
TIM_ITConfig(TIM2, TIM_IT_Update | TIM_IT_CC1 | TIM_IT_CC2, ENABLE); //允许更新中断 ,允许捕获中断
TIM_Cmd(TIM2, ENABLE); //使能
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;//抢占优先级
NVIC_InitStructure.NVIC_IRQChannelSubPriority =3; //子优先级
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能
NVIC_Init(&NVIC_InitStructure); //根据指定的参数初始化VIC寄存器
}
void TIM2_IRQHandler(void)
{
Cap_Data1 = TIM2->CCR1; //读取CCR1也可以清CC1IF标志位
if(Cap_Data1 != 0 )
{
Fre_Cap = 8.4 * 1000000/Cap_Data1;
zhouqi_Cap = 1 / Fre_Cap;
Pwm_Duty = Cap_Data2 * 1.0 /Cap_Data1;
}
Cap_Data2 = TIM2->CCR2; //读取CCR1也可以清CC2IF标志位
TIM2->SR &= ~(1 << 1); //清除中断标志位
}