5 关于串口DMA发送数据一直发不出来

发布于 2020-12-07 18:26:19 浏览：2803 订阅该版

```c
#if defined(BSP_USING_UART5)
void UART5_IRQHandler(void)
{
    /* enter interrupt */
    rt_interrupt_enter();

uart_isr(&(uart_obj[UART5_INDEX].serial));

/* leave interrupt */
    rt_interrupt_leave();
}

#if defined(RT_SERIAL_USING_DMA) && defined(BSP_UART5_RX_USING_DMA)
void UART5_DMA_RX_IRQHandler(void)
{
    /* enter interrupt */
    rt_interrupt_enter();

HAL_DMA_IRQHandler(&uart_obj[UART5_INDEX].dma_rx.handle);

/* leave interrupt */
    rt_interrupt_leave();
}
#endif /* defined(RT_SERIAL_USING_DMA) && defined(BSP_UART5_RX_USING_DMA) */
#if defined(RT_SERIAL_USING_DMA) && defined(BSP_UART5_TX_USING_DMA)
void UART5_DMA_TX_IRQHandler(void)
{
    /* enter interrupt */
    rt_interrupt_enter();

HAL_DMA_IRQHandler(&uart_obj[UART5_INDEX].dma_tx.handle);

/* leave interrupt */
    rt_interrupt_leave();
}
#endif /* defined(RT_SERIAL_USING_DMA) && defined(BSP_UART5_TX_USING_DMA) */
#endif /* BSP_USING_UART5*/
```

这三个中断处理函数，下面的串口DMA发送和接收中断进不去，只能进第一个中断。

```c
static rt_size_t stm32_dma_transmit(struct rt_serial_device *serial, rt_uint8_t *buf, rt_size_t size, int direction)
{
    struct stm32_uart *uart;
    RT_ASSERT(serial != RT_NULL);
    uart = rt_container_of(serial, struct stm32_uart, serial);

if (size == 0)
    {
        return 0;
    }

if (RT_SERIAL_DMA_TX == direction)
    {
        if (HAL_UART_Transmit_DMA(&uart->handle, buf, size) == HAL_OK)
        {
            return size;
        }
        else
        {
            return 0;
        }
    }
    return 0;
}
```
仿真只有发送第一次的时候调用了`HAL_UART_Transmit_DMA()`函数，而且返回`HAL_OK`，但是就是没数据发出来，硬件引脚没错，用轮询的方式能发出来；