在官方core_cm3.h中,有关中断使能,为啥不用或呢,是因为NVIC寄存器组都是写1有效,写0无效
__STATIC_INLINE uint32_t NVIC_GetActive(IRQn_Type IRQn)
{return((uint32_t)(((NVIC->IABR[(((uint32_t)(int32_t)IRQn) >> 5UL)] & (1UL << (((uint32_t)(int32_t)IRQn) & 0x1FUL))) != 0UL) ? 1UL : 0UL));
}