Do the IRQ numbers for interrupts mean anything?
Yes. The lower the IRQ number, the higher the priority of the interrupt. If an interrupt service routine with IRQ number 30 is running, and an interrupt request with IRQ 27 arrives, this new interrupt will preempt the other. But if an interrupt service routine with IRQ 27 is running, and one with IRQ 30 occurs, the first ISR will complete before the next ISR runs. • What do all of the Nios Processor options mean? When you create a Nios Processor, you are prompted to specify several core system options. The following is a brief explanation of what they mean. • The address width of the processor defaults to 21 bits. This means that you have 21 address lines, hence 2^21 distinct addresses. This corresponds to 2 Megabytes of address space. If you were using small RAM chips you might lower this number, and if you needed to address a lot of memory and I/O you would increase it. • The register file size of the processor defaults to 256. This means that you have 256 registers in which to store
