STM32F103 UART中断接收 DMA发送

以USART3为例，

（1）首先在【stm32f1xx_hal_conf.h】中使能DMA模块，工程增加stm32f1xx_hal_dma.c。

（2）main.c中头部增加以下声明

UART_HandleTypeDef huart3;
DMA_HandleTypeDef hdma1_uart3;

（3）main.c中增加USART的初始化

/* USART3 init function */
static void MX_USART3_UART_Init(void)
{
	huart3.Instance = USART3;
	huart3.Init.BaudRate = 115200;
	huart3.Init.WordLength = UART_WORDLENGTH_8B;
	huart3.Init.StopBits = UART_STOPBITS_1;
	huart3.Init.Parity = UART_PARITY_NONE;
	huart3.Init.Mode = UART_MODE_TX_RX;
	huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
	huart3.Init.OverSampling = UART_OVERSAMPLING_16;
	if (HAL_UART_Init(&huart3) != HAL_OK)
	{
		Error_Handler();
	}
}

（4）stm32f1xx_hal_msp.c增加

extern  UART_HandleTypeDef huart3;
extern DMA_HandleTypeDef hdma1_uart3;

......................

void