10 GD32F303CB无法使用RS485组件

发布于 2023-07-03 14:48:00 浏览：618 订阅该版

最近想用485接口和GD32F303做一个485从机，于是想着用官方的RS485组件。
首先第一步骤，调试串口，这里写了一个简单的程序（串口为uart2，波特率115200，PB1输出1为发送模式），然后上电测试了一下通信正常，可以收发：

```c
#define RS485_WP    GET_PIN(B, 1)
#define RS485_TX    rt_pin_write(RS485_WP, PIN_HIGH)
#define RS485_RX    rt_pin_write(RS485_WP, PIN_LOW)
#endif
/* 用于接收消息的信号量 */
static struct rt_semaphore rx_sem;
static rt_device_t serial;
/* 接收数据回调函数 */
static rt_err_t uart_input(rt_device_t dev, rt_size_t size)
{
    /* 串口接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */
    rt_sem_release(&rx_sem);
    return RT_EOK;
}
static void serial_thread_entry(void *parameter)
{
    char ch;
    while (1)
    {
        /* 从串口读取一个字节的数据，没有读取到则等待接收信号量 */
        while (rt_device_read(serial, -1, &ch, 1) != 1)
        {
            /* 阻塞等待接收信号量，等到信号量后再次读取数据 */
            rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
        }
        /* 读取到的数据通过串口错位输出 */
        ch = ch + 1;
        LOG_D("Rx: %c\tTx:%c", ch-1, ch);
#ifdef RS485_WP_PIN
        RS485_TX;
        rt_device_write(serial, 0, &ch, 1);
        RS485_RX;
#endif
    }
}
static int uart_sample()
{
    rt_err_t ret = RT_EOK;
    char uart_name[RT_NAME_MAX];
    char str[] = "hello RT-Thread!\r\n";
#ifdef RS485_WP_PIN
    rt_pin_mode(RS485_WP, PIN_MODE_OUTPUT);
#endif
		rt_strncpy(uart_name, SAMPLE_UART_NAME, RT_NAME_MAX);
    /* 查找系统中的串口设备 */
    serial = rt_device_find(uart_name);
    if (!serial)
    {
        rt_kprintf("find %s failed!\n", uart_name);
        return RT_ERROR;
    }
		 struct serial_configure config = RT_SERIAL_CONFIG_DEFAULT;  /* 初始化配置参数 */
    /* step3：控制串口设备。通过控制接口传入命令控制字，与控制参数 */
    rt_device_control(serial, RT_DEVICE_CTRL_CONFIG, &config);
    /* 初始化信号量 */
    rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);
    /* 以中断接收及轮询发送模式打开串口设备 */
    rt_device_open(serial, RT_DEVICE_FLAG_INT_RX);
    /* 设置接收回调函数 */
    rt_device_set_rx_indicate(serial, uart_input);
#ifdef RS485_WP_PIN
    RS485_TX;
    /* 发送字符串 */
    rt_device_write(serial, 0, str, (sizeof(str) - 1));
    RS485_RX;
#endif
    /* 创建 serial 线程 */
    rt_thread_t thread = rt_thread_create("serial", serial_thread_entry, RT_NULL, 1024, 25, 10);
    /* 创建成功则启动线程 */
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
    else
    {
        ret = RT_ERROR;
    }
    return ret;
}
```
然后直接根据RS485的文档加入了RS485组件的从机，其中具体参数配置如下：

```c
#ifndef RS485_SAMPLE_SLAVE_SERIAL       //UART2
#define RS485_SAMPLE_SLAVE_SERIAL       "uart2"
#endif

#ifndef RS485_SAMPLE_SLAVE_BAUDRATE
#define RS485_SAMPLE_SLAVE_BAUDRATE     115200
#endif

#ifndef RS485_SAMPLE_MASTER_PARITY
#define RS485_SAMPLE_MASTER_PARITY      0 //0 -- none parity
#endif

#ifndef RS485_SAMPLE_SLAVE_PIN          //PB1
#define RS485_SAMPLE_SLAVE_PIN          GET_PIN(B, 1) //-1 -- nonuse rs485 mode control
#endif

#ifndef RS485_SAMPLE_SLAVE_LVL
#define RS485_SAMPLE_SLAVE_LVL          1
#endif

static void rs485_sample_slave_loopback_test(void *args)
{
    static rt_uint8_t buf[256];
    rs485_inst_t *hinst = rs485_create(RS485_SAMPLE_SLAVE_SERIAL, RS485_SAMPLE_SLAVE_BAUDRATE, 
                 RS485_SAMPLE_MASTER_PARITY, RS485_SAMPLE_SLAVE_PIN, RS485_SAMPLE_SLAVE_LVL);

if (hinst == RT_NULL)
    {
        LOG_E("create rs485 instance fail.");
        return;
    }
    rs485_set_recv_tmo(hinst, RT_WAITING_FOREVER);
    if (rs485_connect(hinst) != RT_EOK)
    {
        rs485_destory(hinst);
        LOG_E("rs485 connect fail.");
        return;
    }
    while(1)
    {
        int len = rs485_recv(hinst, buf, sizeof(buf));
        if (len > 0)
        {
            rs485_send(hinst, buf, len);
        }
    }
}

static int rs485_sample_slave_init(void)
{
    rt_thread_t tid = rt_thread_create("rs485slave", rs485_sample_slave_loopback_test, RT_NULL, 1024, 8, 20);
    RT_ASSERT(tid != RT_NULL);
    rt_thread_startup(tid);
    LOG_I("rs485 sample slave thread startup...");
    return(RT_EOK);
}
INIT_APP_EXPORT(rs485_sample_slave_init);
```
反复查看可debug,觉得参数设置应该都是正确的，但是到了下面这一步就直接卡死了，而且上位机发数据也不行：

![微信图片_20230703144436.png](https://oss-club.rt-thread.org/uploads/20230703/56e3e23dc20b96b42635cc65134589b5.png.webp)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230703/23f39156709f3fdc48a102e34361bf1a.png.webp)

然后，我在while(1)之前加了rs485_send()，也发送不出去数据，所以很疑惑，有没有懂的大佬提供一下解决意见，万分感谢！！！
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230703/53915881e46da34010b039ace2c4db3a.png)