串口dma打开失败要怎么排查

发布于 2021-09-26 21:03:13 浏览：1687 订阅该版

我在初始化串口的时候用dma的方式打不开，但是配置的时候有打开dma选项的，用了串口3打开dma的方式就可以通过初始化，但是我改成串口8就不行了
![image.png](https://oss-club.rt-thread.org/uploads/20210926/72ee63b09a7bd3518dcc97bce075306c.png)
![image.png](https://oss-club.rt-thread.org/uploads/20210926/f66064a1fd6b88ff72dac5cd07f3f12e.png)
```
#define DBUS_DEV_NAME   "uart1"
#define REMOTE_DEV_NAME "uart8"
rt_device_t dbus_dev;
rt_device_t remote_dev;         // 用户遥控串口号

rt_err_t err;
    /********************* 板载DBUS遥控串口初始化 ******************************/
    dbus_dev = rt_device_find(DBUS_DEV_NAME);
    RT_ASSERT(dbus_dev != RT_NULL);

struct serial_configure dbus_config = RT_SERIAL_CONFIG_DEFAULT;
    dbus_config.parity = PARITY_EVEN;
    dbus_config.baud_rate = 100000;
    err = rt_device_control(dbus_dev, RT_DEVICE_CTRL_CONFIG, (void*)&dbus_config);
    RT_ASSERT(err == RT_EOK);

err = rt_device_open(dbus_dev, RT_DEVICE_FLAG_DMA_RX);
    RT_ASSERT(err == RT_EOK);

err = rt_device_set_rx_indicate(dbus_dev, dbus_uart_callback);
    RT_ASSERT(err == RT_EOK);

/********************* 用户遥控串口初始化 ************************/
    remote_dev = rt_device_find(REMOTE_DEV_NAME);
    RT_ASSERT(remote_dev != RT_NULL);

struct serial_configure remote_config = RT_SERIAL_CONFIG_DEFAULT;
    err = rt_device_control(remote_dev, RT_DEVICE_CTRL_CONFIG, (void*)&remote_config);
    RT_ASSERT(err == RT_EOK);

err = rt_device_open(remote_dev, RT_DEVICE_FLAG_DMA_RX);
    RT_ASSERT(err == RT_EOK);

err = rt_device_set_rx_indicate(remote_dev, User_uart8_callback);
    RT_ASSERT(err == RT_EOK);
```
用dma的方式打开串口1的接收也没问题，但是到了串口8就会出错，程序到了下面那里就会报错返回个-8
![image.png](https://oss-club.rt-thread.org/uploads/20210926/45be8e61abb86526d15069169ce6feb6.png)
本人还是初学rtt不久的小白，希望有大佬帮忙解答一下，谢谢！