Nios® II Embedded Design Suite (EDS)
Support for Embedded Development Tools, Processors (SoCs and Nios® II processor), Embedded Development Suites (EDSs), Boot and Configuration, Operating Systems, C and C++
Announcements
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
12434 Discussions

IRQ is disalbed, but ISR is called, Why?

Altera_Forum
Honored Contributor II
775 Views

HI, 

 

UART is interrupt driven. When IRQ for the UART is asserted, its ISR is called. In the ISR, after it reads buffer, it raises an Event. A separate Thread waiting at the Event activated when the Event is posted. In the Thread, it disables IRQ for the Uart. Then it does further processing. I expected that next IRQ will not be served until its IRQ is re-enabled again. But it seems to me that, the ISR has been called during the IRQ is disabled. Can anyone help me explain why? 

 

Thank you, 

David
0 Kudos
0 Replies
Reply