Nios® V Processor Software Developer Handbook

ID 743810
Date 4/01/2024
Public
Document Table of Contents

8.2.3.1. Methods the HAL Uses to Register the ISR

The HAL registers the ISR by storing the function pointer (isr), in a lookup table.

The return code from alt_ic_isr_register() is zero if the function succeeded, and nonzero if it failed. If the HAL registers your ISR successfully, the associated Nios® V processor hardware interrupt (as defined by irq) is enabled on return from alt_ic_isr_register(). Each Nios® V processor hardware interrupt can register a single ISR only, and changing ISR on run-time is not supported.

For more information about alt_ic_isr_register(), refer to the HAL API Reference chapter.

Note: Registering the ISR can require hardware-specific initialization. The HAL code ensures that the registered ISR is correctly dispatched when a specific interrupt occurs. For more information and details about hardware interrupt initialization specific to your peripheral, refer to the relevant chapter of the Embedded Peripherals IP User Guide.