Nios® II Processor Reference Guide

ID 683836
Date 8/28/2023
Document Table of Contents

5.2.3. Memory Access

The Nios II/f core provides optional instruction and data caches. The cache size for each is user-definable, between 512 bytes and 64 KB.

The memory address width in the Nios II/f core depends on whether the optional MMU is present. Without an MMU, the Nios II/f core supports the bit-31 cache bypass method for accessing I/O on the data master port. Therefore addresses are 31 bits wide, reserving bit 31 for the cache bypass function. With an MMU, cache bypass is a function of the memory partition and the contents of the translation lookaside buffer (TLB). Therefore bit-31 cache bypass is disabled, and 32 address bits are available to address memory.