Question:
Why do I have to re-enable global interrupts?
Response:
Global nterrupts are disabled in Interrupt Service Routines (ISRs) by default. Re-enabling the global interrupts inside an ISR allows the next pending interrupt to be serviced while inside the ISR that enabled global interrupts. If the pending interrupt is lower priority than the one that enabled global interrupts, it will still be serviced.
Note: If you enable global interrupts inside an ISR that posts interrupts faster than they can be serviced, you may overflow your stack by constantly entering an ISR without exiting it.
看来是相同的 |