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Altera_Forum's avatar
Altera_Forum
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10 years ago

questions about nios interrupts

hi everyone. there are 2 interrupts in my project interrupt A has lower poriority than interrupt B i think if the interrupt B comes when the code is executing the interrupt A's handler, the c...
Altera_Forum's avatar
Altera_Forum
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10 years ago

The internal interrupt controller of Nios does not allow interrupt preemption. You will need to upgrade to external interrupt controller and add the Altera Vectored Interrupt Controller (VIC), which is a Nios peripheral that allow better interrupt handling including interrupt masking.

Refer to section 32: https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/ug/ug_embedded_ip.pdf

With the VIC, you can set interrupt B to be non-maskable so that it can take over the lower priority interrupt (interrupt A). Which means that interrupt B ISR can be entered even when interrupt A is being serviced.