CC2530 ZigbeeStack中功耗管理是如何实现的？

1、CC2530 ZigbeeStack中功耗管理是如何实现的？

方法：动态调整睡眠定时器的溢出周期，MCU进入睡眠模式，由睡眠定时器中断或者外部中断唤醒MCU

2、程序实现：

（1）void osal_pwrmgr_powerconserve( void )

（2）uint32 osal_next_timeout( void )

（3）void halSleep( uint32 osal_timeout )

不理解void halSleep( uint32 osal_timeout )中的轮询，时间递减的原理。

（1）为什么每次减去的是HAL_SLEEP_MS_TO_320US( MAX_SLEEP_TIME );

（2）设置电源模式： HAL_SLEEP_SET_POWER_MODE()中， HAL_DISABLE_INTERRUPTS();

唤醒源：睡眠定时器中断或者外部中断，但是这里关闭了中断，那系统是如何唤醒的？？

      do
      {
        /* enable sleep timer interrupt */
        if(timeout != 0)
        { 
          if (timeout > HAL_SLEEP_MS_TO_320US( MAX_SLEEP_TIME ))
          {
            timeout -= HAL_SLEEP_MS_TO_320US( MAX_SLEEP_TIME );
            halSleepSetTimer(HAL_SLEEP_MS_TO_320US( MAX_SLEEP_TIME ));
          }
          else
          {
            /* set sleep timer */
            halSleepSetTimer(timeout);
            timeout = 0;
          }
          
          /* set up sleep timer interrupt */
          HAL_SLEEP_TIMER_CLEAR_INT();
          HAL_SLEEP_TIMER_ENABLE_INT();
        }
				
        /* Prep CC2530 power mode */
        HAL_SLEEP_PREP_POWER_MODE(halPwrMgtMode);

        /* save interrupt enable registers and disable all interrupts */
        HAL_SLEEP_IE_BACKUP_AND_DISABLE(ien0, ien1, ien2);
        HAL_ENABLE_INTERRUPTS();

        /* set CC2530 power mode, interrupt is disabled after this function
         * Note that an ISR (that could wake up from power mode) which runs
         * between the previous instruction enabling interrupts and before
         * power mode is set would switch the halSleepPconValue so that
         * power mode shall not be entered in such a case. 
         */
        
        HAL_SLEEP_SET_POWER_MODE();
        
        /* the interrupt is disabled - see halSetSleepMode() */
        
        /* restore interrupt enable registers */
        HAL_SLEEP_IE_RESTORE(ien0, ien1, ien2);

        /* disable sleep timer interrupt */
        HAL_SLEEP_TIMER_DISABLE_INT();

      } while(timeout != 0);