先来介绍一下UART空闲中断。UART常用的接收中断响应有：接收数据 就绪可读中断RXNE（这是最常用的）、数据溢出中断（ORE）、奇偶校验错中断（PE）和空闲中断（IDLE）。空闲中断是指当总线检测到一帧发完后， 总线空闲则会将此位置一，如果USART_CR1中的IDLEIE为’1’，则产生中断。空闲中断有两个比较有意思的特点：
1、清零方式：软件清零，先读USART_SR，然后读USART_DR
2、直到RXNE被置一后IDLE才能被重读置一，即IDLE被置一并软件清零后，只有之后再次接收到数据，IDLE才能被置一。这样就防止了总线长时间空闲而多次引发空闲中断。
好的废话不多说上例程。
以下都是通过DMA接收GPS串口的子模块程序
#define UART_RX_LEN 128
static char Uart_Rx[UART_RX_LEN];//GPS接收数据
void GPS_Init(void)
{
RCC_Configuration();//时钟打开
GPIO_Configuration();//GPIO配置
DMA_Configuration();//DMA配置
UART_Configuration();//UART配置
NVIC_Configuration();//中断优先级配置
}
void RCC_Configuration(void)
{
//打开串口对应的外设时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
//启动DMA时钟
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
}
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
void DMA_Configuration(void)
{
DMA_InitTypeDef DMA_InitStructure;
//DMA1通道5配置
DMA_DeInit(DMA1_Channel5);
//外设地址
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART1->DR);
//内存地址
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Uart_Rx;
//dma传输方向单向
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
//设置DMA在传输时缓冲区的长度
DMA_InitStructure.DMA_BufferSize = UART_RX_LEN;
//设置DMA的外设递增模式，一个外设
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
//设置DMA的内存递增模式
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
//外设数据字长
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
//内存数据字长
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
//设置DMA的传输模式
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
//设置DMA的优先级别
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
//设置DMA的2个memory中的变量互相访问
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel5,&DMA_InitStructure);
//使能通道5
DMA_Cmd(DMA1_Channel5,ENABLE);
}
void UART_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
//初始化参数
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_InitStructure.USART_BaudRate = 9600;
//初始化串口
USART_Init(USART1,&USART_InitStructure);
//中断配置
USART_ITConfig(USART1,USART_IT_TC,DISABLE);
USART_ITConfig(USART1,USART_IT_RXNE,DISABLE);
USART_ITConfig(USART1,USART_IT_IDLE,ENABLE);
//采用DMA方式接收
USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);
}
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
//配置UART1中断
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; //通道设置为串口1中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; //中断占先等级0
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //中断响应优先级0
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //打开中断
NVIC_Init(&NVIC_InitStructure);
}
void USART1_IRQHandler(void)
{
uint32_t Length = 0;//数据长度
if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)
{
DMA_Cmd(DMA1_Channel5,DISABLE);
Length = USART1->SR;
Length = USART1->DR; //清USART_IT_IDLE标志
Length = UART_RX_LEN - DMA_GetCurrDataCounter(DMA1_Channel5);
//设置传输数据长度
DMA1_Channel5->CNDTR = UART_RX_LEN;//重装填,并让接收地址偏址从0开始
DMA_Cmd(DMA1_Channel5, ENABLE);//处理完,重开DMA
}
__nop();
}
void GPS_Cmd(FunctionalState NewState)
{
USART_Cmd(USART1, NewState);
}
以下是调用函数，一般在main函数中
GPS_Init();
GPS_Cmd(ENABLE);
此程序经过博主亲测，有效可用。
