5 PM2.0 外部中断唤醒后程序执行顺序异常

发布于 2022-07-07 11:08:23 浏览：829 订阅该版

设备为stm32L071，rtt是github上下载的最新版4.1.1。在调试pm功能时遇到问题：
1.可以进入STOP模式，tickless使用lptim，工作正常，软件定时器可以主动唤醒。
2.当使用外部中断唤醒stop模式后，串口工作不正常，debug发现唤醒后竟然先执行了中断服务函数，然后切换到等待信号量的线程，直到idle后才会执行中的睡眠前的代码处，这时才执行恢复时钟函数。
pm睡眠前应该是禁用了全局中断的，只发生pending不执行ISR才对，为什么会有这种问题呢？

```c
static void rx_thread_entry(void *param)
{
	  while(1)
    {
			  if (rt_sem_take(rx_sem, RT_WAITING_FOREVER) == RT_EOK)
				{
					  rt_pm_sleep_request(PM_BOARD_ID, PM_SLEEP_MODE_NONE);
					  do something //此时串口异常，LOG等功能输出乱码
					  rt_thread_mdelay(5);  //执行到此处，才跳转到睡眠前位置，恢复时钟
					  rt_thread_mdelay(5000);
					  rt_pm_sleep_release(PM_BOARD_ID, PM_SLEEP_MODE_NONE);
				}
		}
}

void lora_rx_irq_callback(void *parameter)
{
	  rt_sem_release(rx_sem); //先执行此行，释放信号量
}
```

pm适配代码如下：
```C
static void sleep(struct rt_pm *pm, uint8_t mode)
{
    switch (mode)
    {
    case PM_SLEEP_MODE_NONE:
        break;

case PM_SLEEP_MODE_IDLE:
    case PM_SLEEP_MODE_LIGHT:
        /* Enter SLEEP Mode, Main regulator is ON */
        HAL_PWR_EnterSLEEPMode(PWR_MAINREGULATOR_ON, PWR_SLEEPENTRY_WFI);
        break;

case PM_SLEEP_MODE_DEEP:
        /* Disable SysTick interrupt */
        CLEAR_BIT(SysTick->CTRL, (rt_uint32_t)SysTick_CTRL_TICKINT_Msk);
        /* Enable the Ultra Low Power mode and the fast wake up */
        SET_BIT(PWR->CR, PWR_CR_ULP | PWR_CR_FWU);
        /* Select HSI as system clock source after Wake Up from Stop mode */
        //__HAL_RCC_WAKEUPSTOP_CLK_CONFIG(RCC_STOP_WAKEUPCLOCK_HSI);
        /* Enter STOP mode  */
        HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
        /* Disable the Ultra Low Power mode and the fast wake up */
        CLEAR_BIT(PWR->CR, PWR_CR_ULP | PWR_CR_FWU);
        /* Enable SysTick interrupt */
        SET_BIT(SysTick->CTRL, (rt_uint32_t)SysTick_CTRL_TICKINT_Msk);
		/* Re-configure the system clock */
        SystemClock_ReConfig();
        
        break;

case PM_SLEEP_MODE_STANDBY:
    case PM_SLEEP_MODE_SHUTDOWN:
        __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
        /* Enter STANDBY mode */
        HAL_PWR_EnterSTANDBYMode();
        break;

default:
        RT_ASSERT(0);
        break;
    }
}
```