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NIOS Nested Interrupts

Honored Contributor II

Morning All, 

I was wondering if anybody could point me to some example/reference designs using nested interrupts with the NIOS. What documentation I've read said there may be ways to do it using an external interrupt controller (I'm using the Altera supplied VIC), but I have been unable to figure it out yet. 


Basically, I want my 1 ms timer interrupt (which has the highest assigned priority on the VIC) callback function to always run - regardless of whether another interrupt is currently being serviced. 


Can anybody provide some pointers (pun not intended) or examples to help me accomplish this? 


Thank you
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1 Reply
Honored Contributor II

The "exception handling (" chapter of the "Nios II Software Developer’s Handbook" covers this very thoroughly. This doc also refers to the "Vectored Interrupt Controller Core" chapter of the "embedded peripherals ip user guide (", which has further guidance. 


If you've not found these two docs then you now have them. They cover the behaviour of Nios' interrupt system very thoroughly and have various examples - some more helpful than others. 


Hope they help.