rt_thread_delay中，关/开中断，导致SPI从机接收时数据丢失

发布于 2020-09-20 16:48:57 浏览：1679 订阅该版

rt_thread_delay函数中，从关中断到开中断，时间太长，导致MCU作为SPI从机，采用5MHZ通信时，接收丢失数据，
```c
rt_err_t rt_thread_sleep(rt_tick_t tick)
{
    register rt_base_t temp;
    struct rt_thread *thread;

/* disable interrupt */
    temp = rt_hw_interrupt_disable();
    /* set to current thread */
    thread = rt_current_thread;
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

/* suspend thread */
    rt_thread_suspend(thread);

/* reset the timeout of thread timer and start it */
    rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME, &tick);
    rt_timer_start(&(thread->thread_timer));

/* enable interrupt */
    rt_hw_interrupt_enable(temp);

rt_schedule();

/* clear error number of this thread to RT_EOK */
    if (thread->error == -RT_ETIMEOUT)
        thread->error = RT_EOK;

return RT_EOK;
}
```
从`rt_hw_interrupt_disable()`到`rt_hw_interrupt_enable(temp)`，MCU执行的时间超过了SPI接收8字节的时间，导致SPI口（从机）接收数据丢失。

建议修改内核中使用`PRIMASK`开关中断的方法，而采用与`FreeRTOS`中的修改BASEPRI的方法。