|
最近想使用STM32F103的定时器捕获功能测量两个方波输入信号的延迟,使用TIM2的ch1和ch2,都设置为上升沿捕获,使能定时器输入捕获中断,在定时器当中处理延迟测量。定时器初始化部分代码如下:
static void TIM2_NVIC_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
static void TIM2_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_ICInitTypeDef TIM_ICInitStructure;
// TIM2 clock enable
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
// GPIOA clock enable
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
// TIM2 channel1 pin(PA.00) configuration
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
// CH1 configuration: Input Capture mode, Rising Edge
TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
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);
// TIM2 channel2 pin(PA.01) configuration
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
// CH2 configuration: Input Capture mode, Rising Edge
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 enable counter */
TIM_Cmd(TIM2, ENABLE);
/* Enable the CC1/CC2 Interrupt Request */
TIM_ITConfig(TIM2, TIM_IT_CC1, ENABLE);
TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);
}
void Timer_Init(void)
{
TIM2_NVIC_Config();
TIM2_Config();
}
TIM2中断处理部分代码如下:
void TIM2_IRQHandler(void)
{
if(TIM_GetITStatus(TIM2, TIM_IT_CC1) == SET)
{
/* Clear TIM2 Capture compare interrupt pending bit */
TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);
if(CaptureNumber == 0)
{
/* Get the Input Capture value */
IC3ReadValue1 = TIM_GetCapture2(TIM2);
CaptureNumber = 1;
}
}
if(TIM_GetITStatus(TIM2, TIM_IT_CC2) == SET)
{
/* Clear TIM2 Capture compare interrupt pending bit */
TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
if(CaptureNumber == 1)
{
/* Get the Input Capture value */
IC3ReadValue2 = TIM_GetCapture2(TIM2);
CaptureNumber = 0;
/* Capture computation */
if (IC3ReadValue2 > IC3ReadValue1)
{
Capture = (IC3ReadValue2 - IC3ReadValue1);
}
else
{
Capture = ((0xFFFF - IC3ReadValue1) + IC3ReadValue2);
}
}
}
}
定时器驱动时钟为72MHz,外部输入两路信号均为3KHz,两路信号相位差为70deg,但目前得到的Capture始终为24000,不知是和缘故。是否还需要其他什么配置才能够保证用同一个计数器的两个通道捕获?求教。
|
阿莫论坛20周年了!感谢大家的支持与爱护!!
一只鸟敢站在脆弱的枝条上歇脚,它依仗的不是枝条不会断,而是自己有翅膀,会飞。
|