5 studio配置SD卡和虚拟文件系统，测试SD卡写入速度只有100多KB/s？

发布于 2020-09-15 14:11:27 浏览：2580 订阅该版

我用rtthread studio中的sd卡使用虚拟文件系统例程写入数据，我测的写入速度为120kb/s，看了下它的有关于sd卡初始化的代码，看不太懂，然后看了下原子的sd卡初始化过程，发现sd卡初始化后需要再设置下时钟，但是在rtt里面我没有找到相关的配置，有大佬知道什么原因导致速度过慢吗？怎么解决，求教，测试sd卡写入速度代码如下：

```c
    int fd, size;
    float speed ;
    float speed_time;
    int i;
    char buf[20];
    int8_t s[256] = "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!"
            "RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer! RT-Thread Programmer!";
    char buffer[80];

/* 以创建和读写模式打开 /text.txt 文件，如果该文件不存在则创建该文件 */

rt_kprintf("Write ...........\n");
    rt_kprintf("tick is :%d !\n", rt_tick_get());
    speed =  rt_tick_get();
    fd = open("/text.txt", O_WRONLY | O_CREAT | O_APPEND);
    if (fd>= 0)
    {
        for (i = 0; i < 1024; ++i) {
            write(fd, s, sizeof(s));
        }
        close(fd);
        rt_kprintf("tick is :%d !\n", rt_tick_get());
        speed = rt_tick_get()-speed;
        speed_time = 1000/speed;
        speed_time = (sizeof(s)*speed_time);
        sprintf((char*)buf, "%3.1f",(float)speed_time);
        rt_kprintf("Write done. speed：%f kb/s\n",speed_time);
    }
      /* 以只读模式打开 /text.txt 文件 */
    fd = open("/text.txt", O_RDONLY);
    if (fd>= 0)
    {
        size = read(fd, buffer, sizeof(buffer));
        close(fd);
//        rt_kprintf("Read from file test.txt : %s \n", buffer);
        if (size < 0)
            return ;
    }

}
```