EXTI->IMR |= 1<<0; HAL_NVIC_SetPriority(EXTI0_IRQn, 15, 0); HAL_NVIC_EnableIRQ(EXTI0_IRQn); __HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE); //使能IDLE中断 HAL_UART_Receive_DMA(&huart1,rx1_buffer,BUFFER_SIZE); //启动串口DMA接收 HAL_TIM

看起来这是一段代码，但是似乎缺少了一些内容。这段代码主要是针对 STM32 系列芯片进行配置，设置了外部中断、串口接收和定时器等功能。其中，开启了串口 DMA 接收，可以实现在接收数据时不占用 CPU 资源，提高系统的并发性能。同时也开启了 UART 的 IDLE 中断，当接收到空闲帧时会触发该中断，可以通过中断服务函数进行处理。对于这段代码的具体作用和意义，需要结合整个项目的需求和功能来分析。

相关问题

EXTI->IMR的功能和作用并举例说明一下用法

EXTI->IMR是STM32F4系列芯片外部中断控制寄存器，用于控制外部中断线的中断使能。每个外部中断线都对应EXTI->IMR寄存器的一位，当对应位为1时，表示该外部中断线使能，可以触发中断服务程序；当对应位为0时，表示该外部中断线禁止，不会触发中断服务程序。

例如，若要使能外部中断线0和2，可以用以下代码实现：

EXTI->IMR |= 0x0005;  //使能外部中断线0和2

其中，0x0005的二进制表示为0000 0000 0000 0101，对应到EXTI->IMR寄存器的位上，就是将第0位和第2位设置为1，表示使能外部中断线0和2。这样，当外部中断线0或2产生中断事件时，就会触发中断服务程序。

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);
}