Why does Nios® V/c processor fail to service interrupts when it is under CLINT-Vectored mode?

Description

Due to a problem in the Quartus^® Prime Pro Edition Software version 25.3.1, the Nios^® V/c processor might fail to service any interrupts when it is under CLINT-Vectored mode. The affected interrupts are platform interrupts, software interrupt, and timer interrupt. 

The following are not affected by this issue: 

• Nios^® V/c processor under CLINT-Direct,  
• Nios^® V/m processor, and  
• Nios^® V/g processor 

This is because the Board Support Package Editor fails to generate relevant macros in system.h to support CLINT-Vectored mode.

Resolution

To continue using CLINT-Vectored with Nios^® V/c processor, add the following macros in the system.h. 

#define ALT_CPU_INT_MODE 1  #define NIOSVSMALLCORE_INT_MODE 1  #define INTEL_NIOSV_C_0_DM_AGENT_INT_MODE 1 

This problem is scheduled to be fixed in a future release of the Quartus^® Prime Pro Edition Software version 26.1.