关于江协科技的中断实验

在江协科技的stm32的中断实验的视频中的实验。为什么最后即使加了再次判断引脚电平，但是还是不稳定，还会有跳变啊？有没有大神解答一下疑惑？

附代码：

#include "stm32f10x.h"                  // Device header

int16_t Encoder_Count;

void Encoder_Init(void)

{

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource0);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource1);

EXTI_InitTypeDef EXTI_InitStructure;
EXTI_InitStructure.EXTI_Line = EXTI_Line0 | EXTI_Line1;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_Init(&EXTI_InitStructure);

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_Init(&NVIC_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_Init(&NVIC_InitStructure);


}

int16_t Encoder_Get(void)

{

int16_t Temp;

Temp = Encoder_Count;

Encoder_Count = 0;

return Temp;

}

void EXTI0_IRQHandler(void)

{

if (EXTI_GetITStatus(EXTI_Line0) == SET)

{

/ *如果出现数据乱跳的现象，可再次判断引脚电平，以避免抖动* /

if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_0) == 0)

{

if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_1) == 0)

{

Encoder_Count --;

}

}

EXTI_ClearITPendingBit(EXTI_Line0);

}

}

void EXTI1_IRQHandler(void)

{

if (EXTI_GetITStatus(EXTI_Line1) == SET)

{

/ *如果出现数据乱跳的现象，可再次判断引脚电平，以避免抖动* /

if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_1) == 0)

{

if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_0) == 0)

{

Encoder_Count ++;

}

}

EXTI_ClearITPendingBit(EXTI_Line1);

}

}