关于SYSTICK中断优先级的问题

只看该作者 · 2012-12-15 20:06

/* Configure the NVIC Preemption Priority Bits配置优先级组 */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
/* 2 bits for pre-emption priority:0-3
2 bits for subpriority:0-3*/

/* Enable the USART3 Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority =0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority =1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* enabling TIM1 interrupt */ //抢占级0，响应级0 采样点间隔计时器0.5ms
  NVIC_InitStructure.NVIC_IRQChannel=TIM1_CC_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

   /* Enable the TIM3 gloabal Interrupt */ //采样周期计时器20ms
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority =2;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority =3;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  NVIC_SetPriority(SysTick_IRQn,15);
}
如上程序，我设的抢占优先级为2位（0-3），亚优先级也是2位（0-3），然后设的Systick的优先级为15（默认的优先级），这样话Systick中断到底比其他的优先级都低呢还是都高呀