NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2

这行代码是针对 NVIC（Nested Vectored Interrupt Controller，嵌套向量中断控制器）配置的一部分。在这里，我们设置了 `NVIC_IRQChannelSubPriority` 字段的值为 2。

NVIC 是 ARM 处理器上的一个重要组件，用于管理中断。`NVIC_IRQChannelSubPriority` 字段指定了中断通道的子优先级。子优先级用于在同一优先级组内进一步排序中断优先级。

通过将 `NVIC_IRQChannelSubPriority` 设置为 2，我们指定了该中断通道的子优先级为 2。这意味着，在同一优先级组内，具有较低优先级值的中断将比具有较高优先级值的中断优先执行。

请注意，具体的设置和作用还取决于你在代码其他部分所做的配置和使用。

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VIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

这段代码是用于配置 NVIC（Nested Vectored Interrupt Controller）的中断优先级的。以下是对这段代码的解释：

VIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;     // 中断抢占优先级设置为2
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;           // 中断子优先级设置为2

在 ARM Cortex-M 系列处理器中，中断优先级分为抢占优先级（Preemption Priority）和子优先级（Sub Priority），用于确定中断的优先级顺序。抢占优先级用于确定是否可以打断其他正在执行的中断或任务，而子优先级用于确定同一抢占优先级的多个中断之间的优先级顺序。

在这段代码中，`VIC_InitStructure` 是一个结构体变量，用于配置 NVIC 的相关参数。通过设置 `NVIC_IRQChannelPreemptionPriority` 和 `NVIC_IRQChannelSubPriority` 成员，我们可以指定特定中断通道的抢占优先级和子优先级。

具体的优先级数值可以根据实际需求进行调整，数值越小表示优先级越高。需要注意的是，不同的处理器和芯片可能对中断优先级的范围和位数有所限制，所以在设置中断优先级时需要参考相关文档和芯片手册的规定。此外，还要根据具体的应用场景和中断处理的要求，合理设置不同中断的优先级顺序。

在保持原来的代码逻辑的条件下，根据STM32F407的特性，把下面STM32F1的代码移植到STM32F407。void ExtiGpioInit(void) { GPIO_InitTypeDef GPIO_InitStruct; RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_AFIO, ENABLE); GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_InitStruct.GPIO_Pin = GPIO_Pin_4|GPIO_Pin_5 ; GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOC, &GPIO_InitStruct); } void ExtiNvicInit(void) { NVIC_InitTypeDef NVIC_InitStructure; NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn ; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); } void ExtiModeInit(void) { EXTI_InitTypeDef EXTI_InitStructure; GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource4); EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; EXTI_InitStructure.EXTI_Line = EXTI_Line4; EXTI_InitStructure.EXTI_LineCmd = ENABLE; EXTI_Init(&EXTI_InitStructure); GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource5); EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; EXTI_InitStructure.EXTI_Line = EXTI_Line5; EXTI_InitStructure.EXTI_LineCmd = ENABLE; EXTI_Init(&EXTI_InitStructure); }

void ExtiGpioInit(void)
{
GPIO_InitTypeDef GPIO_InitStruct;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_4|GPIO_Pin_5 ;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOC, &GPIO_InitStruct);

}

void ExtiNvicInit(void)
{
NVIC_InitTypeDef NVIC_InitStructure;

NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn ;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}

void ExtiModeInit(void)
{
EXTI_InitTypeDef EXTI_InitStructure;

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource4);
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_Line = EXTI_Line4;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource5);
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_Line = EXTI_Line5;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
}