Nios® II Processor Reference Guide

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

2.6.3. Tightly-Coupled Memory

Tightly-coupled memory provides guaranteed low-latency memory access for performance-critical applications. Compared to cache memory, tightly-coupled memory provides the following benefits:
  • Performance similar to cache memory
  • Software can guarantee that performance-critical code or data is located in tightly-coupled memory
  • No real-time caching overhead, such as loading, invalidating, or flushing memory

Physically, a tightly-coupled memory port is a separate master port on the Nios® II processor core, similar to the instruction or data master port. A Nios II core can have zero, one, or multiple tightly-coupled memories. The Nios II architecture supports tightly-coupled memory for both instruction and data access. Each tightly-coupled memory port connects directly to exactly one memory with guaranteed low, fixed latency. The memory is external to the Nios II core and is located on chip.