5 RT-thread studio串口发送，接收只能最大长度3位

发布于 2021-11-21 22:19:23 浏览：1194 订阅该版

遇到奇怪的问题，固定输出123456可以正常接收显示，动态数值只能接收最多3位。
main.c代码
![image.png](https://oss-club.rt-thread.org/uploads/20211121/7b2901d53a2bfa2a35049a747833fdce.png)

cgg是int类型

如下为串口发送代码：
```
#include <rtthread.h>

#define SAMPLE_UART_NAME       "uart2"       /* 需要操作的设备 */
static rt_device_t serial;                   /* 设备句柄 */
//static char str[] = "123456\r\n";  /* 需要发送的数据 */
void uart_send(char *str)
//void uart_send()
{
    rt_err_t ret = RT_EOK;
    rt_size_t send_len = 0;

/* 查找系统中的串口设备 */
    serial = rt_device_find(SAMPLE_UART_NAME);
    if (!serial)
    {
        rt_kprintf("find %s failed!\n", SAMPLE_UART_NAME);
    }

/* 以中断接收及轮询发送模式打开串口设备 */
    ret = rt_device_open(serial, RT_DEVICE_FLAG_INT_RX);
    if (ret != RT_EOK)
    {
        rt_kprintf("open device failed\r\n");
    }
    /* 发送字符串 */
    send_len = rt_device_write(serial, 0, str, (sizeof(str) - 1));
    if (send_len != sizeof(str) - 1)
    {
        rt_kprintf("send data failed\r\n");
    }
    /* 关闭设备 */
    ret = rt_device_close(serial);
    if (ret != RT_EOK)
    {
        rt_kprintf("close device failed\r\n");
    }

//rt_kprintf("serial device test successful\r\n");

}

固定发送123456，串口接收到的是正常的：

![image.png](https://oss-club.rt-thread.org/uploads/20211121/aaf6dc7b65ed6e66801853c8889ed027.png)

```
动态传值过来，串口接收最多只能长度3位。

![image.png](https://oss-club.rt-thread.org/uploads/20211121/1674ab3ca147a3e959ccf64eee628434.png)