Nios II Classic Processor Reference Guide

ID 683620
Date 10/28/2016
Document Table of Contents Memory and Peripheral Access

The Nios II architecture provides memory-mapped I/O access. Both data memory and peripherals are mapped into the address space of the data master port. The Nios II architecture uses little-endian byte ordering. Words and halfwords are stored in memory with the more-significant bytes at higher addresses.

The Nios II architecture does not specify anything about the existence of memory and peripherals; the quantity, type, and connection of memory and peripherals are system-dependent. Typically, Nios® II processor systems contain a mix of fast on-chip memory and slower off-chip memory. Peripherals typically reside on-chip, although interfaces to off-chip peripherals also exist.