STM32中 get_timeval tv.tv_usec值

发布于 2021-12-20 13:47:49 浏览：1232 订阅该版

STM32中`get_timeval`  `tv->tv_usec`值一直是0啊？

获取不了？
```c
/**
 * Get time from RTC device (without timezone, UTC+0)
 * @param tv: struct timeval
 * @return the operation status, RT_EOK on successful
 */
static rt_err_t get_timeval(struct timeval *tv)
{
#ifdef RT_USING_RTC
    static rt_device_t device = RT_NULL;
    rt_err_t rst = -RT_ERROR;

if (tv == RT_NULL)
        return -RT_EINVAL;

/* default is 0 */
    tv->tv_sec = 0;
    tv->tv_usec = 0;

/* optimization: find rtc device only first */
    if (device == RT_NULL)
    {
        device = rt_device_find("rtc");
    }

/* read timestamp from RTC device */
    if (device != RT_NULL)
    {
        if (rt_device_open(device, 0) == RT_EOK)
        {
            rst = rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &tv->tv_sec);
            rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIMEVAL, tv);
            rt_device_close(device);
        }
    }
    else
    {
        /* LOG_W will cause a recursive printing if ulog timestamp function is enabled */
        rt_kprintf("Cannot find a RTC device to provide time!\r\n");
        return -RT_ENOSYS;
    }

return rst;

#else
    /* LOG_W will cause a recursive printing if ulog timestamp function is enabled */
    rt_kprintf("Cannot find a RTC device to provide time!\r\n");
    return -RT_ENOSYS;
#endif /* RT_USING_RTC */
}
```