关于RTC闹钟驱动rt_alarm_start

发布于 2020-03-26 17:53:23 浏览：2183 订阅该版

```rt_err_t rt_alarm_start(rt_alarm_t alarm)
{
    rt_int32_t sec_now, sec_old, sec_new;
    rt_err_t ret = RT_ERROR;
    time_t timestamp;
    struct tm now;

if (alarm == RT_NULL)
        return (ret);
    rt_mutex_take(&_container.mutex, RT_WAITING_FOREVER);
    if (!(alarm->flag & RT_ALARM_STATE_INITED))
    {
        if (alarm_setup(alarm, &alarm->wktime) != RT_EOK)
            goto _exit;
    }
    if ((alarm->flag & 0x01) == RT_ALARM_STATE_STOP)
    {
        timestamp = time(RT_NULL);
        localtime_r(×tamp, &now);

alarm->flag |= RT_ALARM_STATE_START;
        /* set alarm */
        if (_container.current == RT_NULL)
        {
            ret = alarm_set(alarm);
        }
        else
        {
            sec_now = alarm_mkdaysec(&now);
            sec_old = alarm_mkdaysec(&_container.current->wktime);
            sec_new = alarm_mkdaysec(&alarm->wktime);

if ((sec_new < sec_old) && (sec_new > sec_now))
            {
                ret = alarm_set(alarm);
            }
            else if ((sec_new > sec_now) && (sec_old < sec_now))
            {
                ret = alarm_set(alarm);
            }
            else if ((sec_new < sec_old) && (sec_old < sec_now))
            {
                ret = alarm_set(alarm);
            }
            else
            {
                ret = RT_EOK;
                goto _exit;
            }
        }

if (ret == RT_EOK)
        {
            _container.current = alarm;
        }
    }

_exit:
    rt_mutex_release(&_container.mutex);

return (ret);
}
```
代码sec_old = alarm_mkdaysec(&_container.current->wktime);sec_new = alarm_mkdaysec(&alarm->wktime);中的sec_old的值与sec_new一样，因为_container.current = alarm指向同一内存地址，下面的IF判断就没意义了。所以使用rt_alarm_control设置参数后用rt_alarm_start启动就会失败，不知道是不是我理解错了，请指点一下，谢谢
NOTE：我是想在闹钟回调函数中使用rt_alarm_control重新设置下一次闹钟事件的时间，然后使用rt_alarm_start启动闹钟，结果发现每次启动失败，还有一点RTT官网上drv_rtc.c中没有对RT_DEVICE_CTRL_RTC_SET_ALARM定义进行处理，无法设置闹钟