#define BSP_USING_UART3
#define BSP_UART3_RX_USING_DMA
#if defined(BSP_USING_UART3)
#define UART3_TX_PORT       GPIOB
#define UART3_RX_PORT       GPIOB
#define UART3_TX_PIN        GPIO_PIN_10
#define UART3_RX_PIN        GPIO_PIN_11
#endif

serial = rt_device_find("uart3");
rt_device_control(serial , RT_DEVICE_CTRL_CONFIG, &config);
rt_device_set_rx_indicate(serial , uart_input);
rt_device_open(serial , RT_DEVICE_FLAG_DMA_RX);
rt_device_write(serial , 0, tx_buffer, sizeof(tx_buffer));
if (rt_sem_take(&rx_sem, rt_tick_from_millisecond(500)) == RT_EOK) {  // dma 接收回调函数释放的信号量
    rt_device_read(serial, 0, rx_buffer, BUFFER_SIZE);
    ...  // 数据处理
}
rt_device_close(serial);