这里教程是选择的STM32F407。STM32F103也测试过。
1.首先选择串口,选择异步通信。
2.添加DMA
3.打开中断
4.生成代码,生成代码选择了每个外设单独使用.c/.h
5.我使用的是Keil5。打开工程,首先注释掉dma.c里的DMA接收中断,因为不需要DMA接收中断,DMA发送中断是需要的。(dma.c)
void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA2_CLK_ENABLE();
/* DMA interrupt init */
/* DMA2_Stream0_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA2_Stream0_IRQn, 2, 0);
HAL_NVIC_EnableIRQ(DMA2_Stream0_IRQn);
/* DMA2_Stream2_IRQn interrupt configuration */
// HAL_NVIC_SetPriority(DMA2_Stream2_IRQn, 0, 0);
// HAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);
/* DMA2_Stream7_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA2_Stream7_IRQn, 1, 0);
HAL_NVIC_EnableIRQ(DMA2_Stream7_IRQn);
}
6.在usart.h文件里定义串口接收数据类型我是如下定义的(usart.h)
/* USER CODE BEGIN Private defines */
#define RECEIVELEN 1024
#define USART_DMA_SENDING 1//发送未完成
#define USART_DMA_SENDOVER 0//发送完成
typedef struct
{
uint8_t receive_flag:1;//空闲接收标记
uint8_t dmaSend_flag:1;//发送完成标记
uint16_t rx_len;//接收长度
uint8_t usartDMA_rxBuf[RECEIVELEN];//DMA接收缓存
}USART_RECEIVETYPE;
extern USART_RECEIVETYPE UsartType1;
/* USER CODE END Private defines */
7.然后在usart.c里需要添加空闲中断处理函数,以及DMA发送函数等。(usart.c)
首先定义串口数据类型:
/* USER CODE BEGIN 0 */
USART_RECEIVETYPE UsartType1;
/* USER CODE END 0 */
然后定义空闲中断处理函数和DMA发送函数
/* USER CODE BEGIN 1 */
#ifdef __GNUC__
/* With GCC/RAISONANCE, small printf (option LD Linker->Libraries->Small printf
set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif /* __GNUC__ */
PUTCHAR_PROTOTYPE
{
HAL_UART_Transmit(&huart1 , (uint8_t *)&ch, 1, 0xFFFF);
return ch;
}
//DMA发送函数
void Usart1SendData_DMA(uint8_t *pdata, uint16_t Length)
{
while(UsartType1.dmaSend_flag == USART_DMA_SENDING);
UsartType1.dmaSend_flag = USART_DMA_SENDING;
HAL_UART_Transmit_DMA(&huart1, pdata, Length);
}
//DMA发送完成中断回调函数
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{
__HAL_DMA_DISABLE(huart->hdmatx);
UsartType1.dmaSend_flag = USART_DMA_SENDOVER;
}
//串口接收空闲中断
void UsartReceive_IDLE(UART_HandleTypeDef *huart)
{
uint32_t temp;
if((__HAL_UART_GET_FLAG(huart,UART_FLAG_IDLE) != RESET))
{
__HAL_UART_CLEAR_IDLEFLAG(&huart1);
HAL_UART_DMAStop(&huart1);
temp = huart1.hdmarx->Instance->NDTR;
UsartType1.rx_len = RECEIVELEN - temp;
UsartType1.receive_flag=1;
HAL_UART_Receive_DMA(&huart1,UsartType1.usartDMA_rxBuf,RECEIVELEN);
}
}
/* USER CODE END 1 */
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8.在中断文件里添加(当然,上面的空闲中断处理函数需要声明)(stm32f4xxit.c)
void USART1_IRQHandler(void)
{
/* USER CODE BEGIN USART1_IRQn 0 */
UsartReceive_IDLE(&huart1);
/* USER CODE END USART1_IRQn 0 */
HAL_UART_IRQHandler(&huart1);
/* USER CODE BEGIN USART1_IRQn 1 */
/* USER CODE END USART1_IRQn 1 */
}
9.主函数里,打开空闲中断,初始化DMA接收
/* USER CODE BEGIN 2 */
HAL_UART_Receive_DMA(&huart1, UsartType1.usartDMA_rxBuf, RECEIVELEN);
__HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
/* USER CODE END 2 */
10.然后就可以在while(1)里处理数据了
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
if(UsartType1.receive_flag)//如果产生了空闲中断
{
UsartType1.receive_flag=0;//清零标记
Usart1SendData_DMA(UsartType1.usartDMA_rxBuf,UsartType1.rx_len);//串口打印收到的数据。
}
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */